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Load management system

1. U S Patent Apr 8 2008 Sheet 2 of 11 US 7 356 384 B2 HOT WATER HEATER 164 POWER TO AIR CONDITIONER POVER WATER HEATER POWER 10 CONTACTER AIR CONDITIONER 2 MAIN DISTRIBUTION PANEL THERMOSTAT 160 UTILITY POWER pe Lis i 1 fan Sy GENERATOR FIG 2 o 2 US 7 356 384 B2 Sheet 3 of 11 Apr 8 2008 U S Patent j euuoosiq 2203 9l ozr uoueig Jeuonipuo2 ON DRY 22 41 77 nnd gzz2zz2zcz24 2 ZAN E A A JOVEN 10H Jexyeeig lJojeJeuac YOUMS um SUV vov 10126 u02 zer oeuuoosi X ARE 00 PEM 828 US 7 356 384 B2 Sheet 4 of 11 Apr 8 2008 U S Patent M anh ts a 1 11 2 t JojeoH 19 M JOH 218 Jojua2 9 914 Jeuonipuo ces yO uuodsiq 2907 uouelg Jayeaig 80S YouMS J9jsugJ I Hos 029 7 25 2 a REM 915 U S Patent Apr 8 2008 Sheet 5 of 11 US 7 356 384 B2 604 Utility drops below 7096 of 240 volts Turn Off Green LED Utility Present Turn on Green LED n io Contacto
2. 15 20 25 30 35 18 close the first signal responsive switch to permit the current from the residential generator to the load after the opening the second signal responsive switch 9 A load management system as set forth in claim 7 wherein the load management system further comprises a sensor adapted to sense first and second electrical signals associated with the load and the air conditioning system respectively wherein the controller is further connected to the sensor and wherein the controller is further configured to determine after receiving the call whether the power required from the residential generator for both the air conditioning system and the load would exceed a preset value the determination being based on the first and second electrical signals determine whether the residential generator can power the air conditioning system after the receiving the call without exceeding the preset value the second deter mination being based on the second electrical signal and open the first signal responsive switch when providing power to both the air conditioning system and the first load would exceed the preset value but powers the air conditioning system and not powering the load would not exceed the preset value 10 A load management system as set forth in claim 9 wherein the sensor comprises a first current transformer associated with the load and a second current transformer associated with the air co
3. difference lt 5 amps value to Relay B Yes 936 Wait 5 minutes to close Relay B FIG 6f US 7 356 384 B2 1 LOAD MANAGEMENT SYSTEM RELATED APPLICATIONS This application claims the benefit of U S Provisional Patent Application No 60 588 073 filed on Jul 15 2004 and U S Provisional Patent Application No 60 676 392 filed on Apr 29 2005 and is a continuation in part of U S patent application Ser No 11 086 167 filed on Mar 22 2005 entitled Residential Load Power Management Sys tem and assigned to the assignee of this application all of which applications are incorporated by reference herein BACKGROUND The invention relates to power management and more particularly to residential power management When there is a residential power outage back up power may be provided by a standby generator In some cases the standby generator is started automatically after the power outage A standby generator that can be started automatically usually requires an automatic transfer switch The combi nation of a standby generator and an automatic transfer switch is generally expensive In some other cases the standby generator will normally be turned on either manu ally or automatically to provide a limited amount of power to the residence due to an amperage limit of the standby generator Therefore only limited power is provided to the residence with some standby generators In other words a standby gener
4. the first signal responsive switch configured to permit a first current from the residential generator to the load a second signal responsive switch configured to be con nected in circuit between the thermostat and the air conditioning system the second signal responsive switch configured to permit a second current from the thermostat to the air conditioning system and a controller connected to the first signal responsive switch and to the second signal responsive switch the con troller being configured to open the second signal responsive switch close the first signal responsive switch to permit the first current from the residential generator to the second load receive a call from the thermostat requesting condi tioned air open the first signal responsive switch to prevent the first current from the residential generator to the load based on receiving the call and close the second signal responsive switch to permit the second current from the thermostat to the air condi tioning system thereby providing the call to the air conditioning system 8 A load management system as set forth in claim 7 wherein the controller is further configured to after provid ing the call receive a cessation of the call from the thermostat to cease the request of conditioned air open the second signal responsive switch to prevent the second current from the thermostat to the air condi tioning system after the receiving the cessation and
5. 536 has warmed up for the amount of time as determined at block 701 the load management control board 144 starts the operation at block 696 Otherwise if the generator 412 536 has not warmed up for the amount of time as determined at block 701 the load management control board 144 keeps the contactor 170 of FIG 2 at the utility position at block 702 and repeats block 604 Continuing with reference to block 700 the load man agement control board 144 then checks to determine if both of the CT s 192 194 are present at block 704 If it is determined at block 704 that the CT s 192 194 are absent from the load management control board 144 the load management control board 144 keeps both of the relays 150 154 open at block 708 Thereafter the load management control board 144 transfers the contactor to the generator position at block 712 However if the CT s 192 194 are present at block 704 the load management control board 144 starts to transfer the contactor 170 to the generator position at block 712 and keep the contactor 170 at the generator position at block 716 for a minimum amount of time In some embodiments the minimum amount of time is about five minutes _ 0 40 45 65 12 As depicted in FIG 65 which is a continuation ofthe flow chart 600 of FIG 6a if the minimum amount of time has elapsed as determined at block 720 the load management control board 144 performs a plurality of operations For exampl
6. for a predetermined minimum amount of time such as five minutes In some embodiments the load management control board 144 can also be configured to perform reverse monitoring For example when the load management control board 144 senses that the utility power 116 has been restored the load management control board 144 will also monitor the utility power for a period of time and will transfer the loads to utility power once the utility source 116 has stabilized In some embodiments when the power transfers from the utility source 116 to the generator 112 the load management control board 144 ensures that the transfer will last for a predetermined mini mum amount of time such as five minutes These minimum time periods avoid some power transfers if the utility power flickers on and off In yet other embodiments the relays 150 and 154 are usually kept closed when utility power is supplied However during a power outage the relays 150 and 154 may be automatically opened to ensure that no power is provided to any connected loads thereby protecting the loads the gen erators and any associated electronics from an instanta neous overload if the managed loads are drawing power when generator power is first supplied The relays 150 and 154 can be controlled by some normally closed contacts In such a case the contacts keep the relay 150 and 154 closed when the utility power is supplied However the solenoid will be de energized or deacti
7. has a lower priority than the first load The method also includes sensing first and second electrical signals from the respective first and second loads and ensuring the first signal responsive switch is in a CLOSED state and the second signal responsive switch in an OPEN state after both a combination of the sensed first and second electrical signals exceeds a first threshold value and the sensed first electrical signal is below a second threshold value While standby backup generator systems that manage load capacity and control an associated transfer switch are generally known these backup systems are typically used in commercial settings such as offices and can be costly These backup systems generally require complicated installation procedures and offer more features than an average resi dence can utilize Some of the offered features and functions can also be impractical for the average residence Further more frequencies and durations of power outages in an average residence are low and short in general respectively As a result an average residence will find it hard to justify the expense for these standby generator systems and for the functions and features that are unnecessary Thus the invention provides the average residence with systems that offer the convenience of being able to manage a limited or reduced number of loads such as an air condi tioning unit and a hot water heater without the expense of more complicated sys
8. load management system 400 includes a main breaker panel box 404 that is connected to a transfer switch 408 and a plurality of loads In the embodiment depicted in FIG 4 the loads include an air conditioner 412 and a hot water heater 416 Particularly the main breaker panel 404 is connected to the air conditioner 412 via a local disconnect 420 and to the hot water heater 416 via a contactor 424 The transfer switch 408 receives the utility power through a watt hour meter 428 and a service disconnect 432 The transfer switch 408 also receives power from a generator 436 Furthermore the main breaker panel 404 can also be connected to a plurality of circuits via some branch circuit outlets 440 in a known manner In the embodiment depicted in FIG 4 the transfer switch 408 also includes the load management control board 144 see FIG 2 However the load management control board 144 can also be imple mented or installed in the main breaker panel box 404 in some other embodiments FIG 5 depicts a third exemplary load management system 500 The third exemplary load management system 500 also includes a transfer switch 504 that is connected to a main breaker panel box 508 and a generator 512 The main breaker panel 508 receives utility power via a watt hour meter 516 The transfer switch 504 is also connected to an emergency load center 520 The emergency load center 520 is connected to a plurality of loads through contactors or a local disco
9. or closed at block 876 If the relay 150 is not closed as determined at block 876 the load management control board 144 determines if the cur rent demand is greater than the preset percentage of the rated generator current at block 880 If it is determined at block 880 that the current demand is at most equal to the percent age rated the load management control board 144 checks to determine if the A C unit is about to start at block 884 and determines if starting the A C unit can result in the current demand being less than the preset percentage at block 888 If the A C unit has not called to start as determined at block 884 or starting the air conditioning unit is not less than the difference block 880 is repeated If the current demand is greater than the percent rated as determined at block 880 the load management control board 144 checks to determine if the current drawn by the load is greater than the total current rated at block 892 If it is determined at block 880 that the load current is less than the preset amount at block 884 that the A C unit is US 7 356 384 B2 15 about to start and at block 888 that starting the A C unit can result in the current drawn being less than the preset per centage or at block 892 that the current demand is greater than the total rated generator current the load management contro board 144 opens the relay 154 and records the current difference between the closed state and the open state o
10. the second priority relay and is connected to the hot water heater 164 if both the A C 162 and the hot water heater 164 are running and drawing a power of 70 percent of the maximum power or wattage capability determined by the load man agement control board 144 and if an additional load such as a microwave oven starts to also demand power from the generator 112 the microwave oven is likely to increase the total power demand to above 85 percent of the maximum power or wattage capability As a result contacts for the second relay 154 connected to the hot water heater 164 will be opened and the first relay 150 will remain closed unless the total current drawn by the microwave oven and the A C 162 is still more than the preset percentage of the maximum 20 25 30 35 40 45 50 55 60 65 8 power or wattage capability with the relay 154 of the hot water heater 164 being in the OPEN state After the micro wave oven stops drawing power from the generator 112 the contacts of the second relay 154 will be closed and thus adding the hot water heater 164 back When stepping loads on and off the load management control board 144 waits for a preset amount of time for example 5 seconds before shedding or adding another prioritized load from or to the load management control board 144 In this way the load management control board 144 has time to stabilize When the load management control board 144 sees or detects a larg
11. thermostat control wire or a thermostat control conductor 160 The load management control board 144 is connected to some high power consumption loads such as an air conditioner 162 and a hot water heater 164 via a contactor 166 Furthermore the transfer switch 120 also includes a second contactor 170 that receives power from the utility source 116 at a utility connection 172 and from the standby generator 112 at a generator connection 178 The contactor 170 also has a load connection 182 that is connected to the loads such as the air conditioner 162 and the hot water heater 164 The transfer switch 120 also includes a neutral terminal 186 for connecting to the neutral inputs of the generator 112 and of the utility source 116 and a ground lug 190 for proper electrical protection To provide power from either the generator 112 or the utility source 116 to the loads such as the air conditioner 162 and the hot water heater 164 the load management control board 144 includes a plurality of prioritized relays 150 154 In some embodiments when the utility source 116 is sup plying power to the residence relays 150 and 154 are not energized and a plurality of contacts remain in a normally closed position However when there is a utility power outage the load management control board 144 takes con trol of the relays 150 and 154 That is after the utility source 116 fails the load management control board 144 starts to transfer to generator powe
12. total current drawn at or below a preset maximum amount for example 85 percent of the rated load of the generator 112 The load management control board 144 generally includes some memory that stores the preset amounts among other things The load management control board 144 also monitors a plurality of power related switches such as the set of power rating switches or jumpers and the set of fuel type switches or jumpers In some embodiments the jumpers and the switches are positioned on the load management control board 144 Alternatively the jumpers and the switches are positioned in the transfer switch 120 The optional power rating switches allow an operator to switch between a plurality of generator output powers for example 10 Kilo watts KW 12 KW 15 KW or 17 KW Of course other generators with different output powers can also be used In some other embodiments the load management con trol board 144 does not include any power rating switches That is the load management control board 144 is set for a particular power rating for example 12 KW The load management control board 144 that offers only a set power rating thus yields a lower cost embodiment Of course other parts can also be eliminated to lower the cost detailed hereinafter Similar to the power rating switches and jumpers the load management control board 144 in some embodiments also provides a plurality of fuel type switches that allow an operator to
13. 6 is a flow chart of processing carried out in embodiments of the invention FIG 6a is a continuation of the flow chart of FIG 6 FIG 65 is a continuation of the flow chart of FIG 6a FIG 6c is a continuation of the flow chart of FIG 65 FIG 6d is a continuation of the flow chart of FIG 6c FIG 6e is a continuation of the flow chart of FIG 64 FIG 6 18 a continuation of the flow chart of FIG DETAILED DESCRIPTION Before any embodiments of the invention are explained in detail it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings The invention is capable of other embodiments and of being practiced or of being carried out in various ways Also it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting The use of including comprising or having and variations thereof herein is meant to encom pass the items listed thereafter and equivalents thereof as well as additional items Unless limited otherwise the terms connected coupled and mounted and variations thereof herein are used broadly and encompass direct and indirect connections couplings and mountings In addition the terms connected and coupled and variations thereof a
14. Generator 716 Contactor to stay on Generator for minimum of 5 minutes FIG 6a U S Patent Apr 8 2008 Sheet 7 of 11 5 minute time period done Are C T s present tility gt 80 0 240 volts Wait 10 seconds for Utility to stabilize Turn on Green LED Open Relays A amp B 0 second tim period done 744 Open Relays A amp B for 5 minutes No 748 Transfer contactor to Utility Turn Off Red LED when Generator voltage 80 Close Relay A FIG 6b US 7 356 384 B2 760 Wait 5 seconds 764 5 second time delay done 768 Close Relay B 772 Reset current values of Relays A amp B to zero U S Patent Apr 8 2008 Sheet 8 of 11 US 7 356 384 B2 5 minute time period done 780 ts the A C called to start Is relay B open Yes Close Relay A Is the load gt 85 rated 808 Is the load gt rated Wait 5 seconds for load to stabilize 804 S the 5 se time delay done No Open Relay A and record current Difference from closed to open FIG 6c U S Patent Apr 8 2008 Sheet 9 of 11 US 7 356 384 B2 820 current difference 5 amps Assign previous value to Relay A o Wait 5 minutes to close Relay A FIG 6d U S Patent Apr 8 2008 Sheet 10 of 11
15. US 7 356 384 B2 832 Wait 5 seconds for Yes load to stabilize 836 Yes Is the called to start No 840 5 sec time delay done Yes 852 closed lt 85 rated Relay B No Yes 856 Close Relay B load gt 6596 rated A start amp be lt gt load gt rated record current Difference from closed to open current difference lt 5 amps 896 Open Relay B and 828 1st time 600 through 860 864 start amp be 85 868 Actual B A 5 min time delay done Yes 865 872 Yes Relay A closed lt 85 No rated Relay B es 876 Is Relay A Yes closed 550 A start amp be lt gt 85 Actual B Wait 5 seconds for load to stabilize s the 5 se time delay done Assign previous value to Relay B Yes 908 Wait 5 minutes to close Relay B FIG 6e U S Patent Apr 8 2008 Sheet 11 of 11 US 7 356 384 B2 948 Yes Is the called to start 920 912 called to No load gt 85 start rated Yes 2 Yes 916 No load rated Wait 5 seconds for load to stabilize Open Relay B and 924 record current Difference from closed to open 932 pee 5 sectime delay done current Yes Assign previous No
16. a2 United States Patent US007356384B2 10 Patent No US 7 356 384 B2 Gull et al 45 Date of Patent Apr 8 2008 54 LOAD MANAGEMENT SYSTEM 56 References Cited 75 Inventors Philip Gull New Berlin WI US U S PATENT DOCUMENTS Wesley C Sodemann Dousman WI 4 066 913 A 1 1978 Manning et al 307 38 US Kenny J Stair North Prairie WI 4 075 699 A 2 1978 Schneider et al US 4 324 987 A 4 1982 Sullivan et al 307 35 4 349 879 A 9 1982 Peddie et al 73 Assignee Briggs amp Stratton Corporation 4 499385 A 2 1985 Slavik Wauwatosa WI US Continued Notice Subject to any disclaimer the term of this patent is extended or adjusted under 35 FOREIGN PATENT DOCUMENTS U S C 154 b by 37 days WO WO 01 37392 5 2001 21 Appl No 11 180 228 OTHER PUBLICATIONS 22 Filed Jul 13 2005 Intellitee SMART EMS Installation and Service Manual P N 65 Prior Publication Data 332244100 Oct 10 1997 Continued US 2006 0018069 Al Jan 26 2006 Continued EM Primary Examiner Zoila Cabrera Related U S Application Data Assistant Examiner Nate Laughlin 63 Continuation in part of application No 11 086 167 74 Attorney Agent or Firm Michael Best amp Friedrich filed on Mar 22 2005 LLP 60 Provisional application No 60 676 392 filed on Apr 29 2005 provisional application No 60 588 073 57 ABSTRACT filed on Jul 15 2004 A method and a system that
17. arly if the current difference is less than a preset amount for example 5 A at block 816 the load management control board 144 assigns a previously determined current value to the relay 150 at block 820 Otherwise if the current difference is not less than the preset amount or after the load management control board 144 has assigned the previously determined current value to the relay 150 at block 820 the load management control board 144 starts a delay for example five minutes at block 824 Thereafter operations in block 776 are repeated Referring to FIG 6e which is a continuation of the flow chart 600 of FIG 6d if the current demand is less than the preset percentage of the rated generator current as deter mined at block 796 of FIG 6c the load management control board 144 checks to determine if it is a first rating check at block 828 If it is determined at block 828 that it is the first rating check the load management control board 144 waits for a set amount of time for example five seconds for the loads to stabilize at block 832 The load manage ment control board 144 then checks to determine if the A C unit is about to start at block 836 If the A C unit is not about to start as determined at block 836 the load management control board 144 checks to determine if a set amount of time for example 5 seconds has elapsed at block 840 However if the A C unit is about to start as determined at block 836 the load mana
18. ator with a low amperage rating can limit the types of and number of appliances connected to the standby generator Exemplary appliances that draw large amounts of current include air conditioners hot water heaters and on demand appliances such as microwave ovens and toast ers Standby back up generators and automatic transfer switches are also known However standby back up gen erators with low power ratings can still be overloaded when more power is demanded than can be supplied by the generators Furthermore standby back up generators with high power ratings are much more costly SUMMARY The invention provides a load management system for managing a plurality of loads in a residence The load management system includes at least one current trans former configured to monitor current input from a standby or portable generator The load management system also includes a plurality of fuel type switches and generator rating switches The fuel type switches allow a user or an operator to select a fuel type used by the generator at installation Similarly the generator rating switches allow the operator to select a generator rating of the generator at installation The load management system also includes a plurality of prioritized relays having the same power ratings Settings of the switches and relay priorities are fixed at installation by the operator Having the same power ratings at all relays simplifies the installation process Whe
19. e the load management control board 144 continues to check if the CT s 192 194 are present at block 724 and checks if the utility voltage is above the second preset percentage at block 728 If it is determined at block 728 that the utility voltage is above the second preset amount of percentage the load management control board 144 will allow an amount of time for example 10 seconds for the utility power to stabilize and turns on the green LED at block 732 However if the utility voltage has not returned to the second preset percentage as determined at block 728 blocks 724 and 728 are repeated If it is determined at block 724 that the CT s 192 194 are absent the load manage ment control board 144 will open both relays 150 154 However if it is determined at block 724 that the CT s 192 194 are present the load management control board 144 will carry out a series of operations discussed below If the load management control board 144 has determined that the amount of time for the utility to stabilize has elapsed at block 740 the load management control board 144 opens up both of the relays 150 154 for an amount of time for example five minutes Because the utility has returned to above the second preset percentage and the pre selected amount of time has elapsed for the utility power to stabilize the load management control board 144 then moves the contactor 170 from the generator position back to the utility position and turns o
20. e current swing in demand the load management control board 144 sheds the loads more quickly to prevent the generator 112 from overloading Once the demand has stabilized the loads can be added again Specifically the load management control board 144 will start adding the applied load with the highest priority available Thereafter the load management control board 144 waits for another preset amount of time for example 5 seconds and adds the next priority load The load management control board 144 will continue to add load until all loads have been added or until the preset maximum amount of rated load has been reached In an alternate lower cost embodiment the load manage ment control board 144 does not perform current monitor ing and does not include any current transformers Instead the load management control board 144 simply opens the relay contacts 150 154 as soon as generator power is sensed The relay contacts 150 154 are kept open until utility power is sensed Any appliances such as the A C 162 or the hot water heater 164 that is electrically connected to the relays 150 154 are locked out after the utility power from the utility source 116 has been restored In such cases the system 100 is less expensive since the CT s 192 194 are eliminated and thus controlling the relays 150 154 is accordingly simplified In some other embodiments the relays 150 154 are selected to search or look for a voltage source that can co
21. f the relay 154 at block 896 If however if the current demand is less than the total rated generator current as determined at block 892 the load management control board 144 starts a delay for example 5 seconds for the load to stabilize at block 558 waits the delay to elapse at block 558 and repeats block 896 or repeats block 550 will be detailed below depending on the elapse of the delay deter mined at block 562 The load management control board 144 then determines if the current difference is less than some preset amount for example 5 A at block 900 If it is determined at block 900 that the current difference is less than the preset amount the load management control board 144 assigns a previously determined current value to the relay 154 at block 904 Otherwise if the current difference is greater than or equal to the preset amount as determined at block 900 the load management control board 144 starts a delay for example five minutes at block 908 and repeats block 780 after the delay Referring back to block 876 that if the relay 150 is not closed block 880 is repeated At block 550 the load management control board 144 checks if the A C unit is about to start The load manage ment control board 144 also checks if starting the A C unit can result in the current drawn being less than the preset amount at block 554 If closing the relay 150 can result in the current drawn being less than the preset amount as determined at b
22. ff ared LED when the generator voltage is less than the second preset percentage at block 748 Once the relays 150 154 have been opened for the amount of time set by the load management control board 144 as determined at block 752 the load management control board 144 closes the relay 150 at block 756 Otherwise the load management control board 144 will wait until the amount of preset time to elapse that is repeats block 752 Once the relay 150 is closed or in the CLOSED state at block 756 the load management control board 144 starts to wait for a fourth preset amount of time at block 760 In some embodiments the fourth preset amount of time is about 5 seconds The load management control board 144 then waits for the fourth preset amount of time to elapse at block 764 Once the fourth preset amount of time has elapsed as determined at block 764 the load management control board 144 then closes the relays 154 at block 768 and resets the recorded current values of the relays 150 154 at block 772 The load management control board 144 then repeats the operation starting at block 612 Referring to FIG 6c which is a continuation of the flow chart 600 of FIG 6a and referring back to blocks 704 FIG 6 and 724 FIG 6a when the load management control board 144 has determined that the CT s 192 194 are present the load management control board 144 determines if an appropriate amount of time has elapsed at block 776 In some embodi
23. gement control board 144 checks to see if closing the relay 150 will result in the current drawn _ 0 35 40 45 50 60 65 14 being less than a preset amount of current for example 85 percent at block 844 If it is determined at block 844 that closing the relay 150 will not result in the current drawn being less than the preset amount of current block 840 is repeated Otherwise if it is determined at block 844 that closing the relay 150 will result in the current drawn being less than the preset amount of current the load manage ment control board 144 checks to determine if the relay 150 is closed at block 848 If it is determined at block 848 that the relay 150 is closed block 840 is repeated If it is determined at block 840 that a delay for example 5 seconds has not elapsed block 836 is repeated Otherwise if it is determined at block 840 that a delay for example 5 seconds has elapsed the load management control board 144 checks to determine if the current demand is at most equal to a second difference between a percentage for example 85 percent of the rated generator current and the current value at the relay 154 at block 852 If the current demand is not less than the second difference block 836 is repeated Otherwise if the current demand is less than the second difference the relay 154 is closed at block 856 In this way both of the relays 150 154 are in a CLOSED state As a result power can be supp
24. in the method further comprises generating a second signal after receiving the call and applying the second signal to the first signal responsive switch and wherein the opening the first signal responsive switch is in response to the applying the second signal 4 A method as set forth in claim 1 wherein the providing the call occurs after the opening the first signal responsive switch 5 A method as set forth in claim 1 wherein the method further comprises determining whether the residential gen erator can power both the air conditioning system and the load after the receiving the call and determining whether the residential generator can power the air conditioning system after receiving the call and wherein the opening the signal responsive switch occurs when the residential generator cannot power both the air conditioning system and the first load but can power the air conditioning system 6 A method as set forth in claim 1 wherein the signal responsive switch comprises a relay 7 A load management system for managing one or more electrical loads of a residence the residence having a US 7 356 384 B2 17 thermostat an air conditioning system and a load unrelated to the air conditioning system the load management system configured to be powered by a residential generator the load management system comprising a first signal responsive switch adapted to be connected in circuit between the residential generator and the load
25. is a continuation of the flow chart 600 in FIG 6 the load management control board 144 then checks the generator voltage at block 672 If the generator voltage is above a second preset percentage as determined at block 672 the load management control board 144 starts a delay such that the generator 436 or 512 can be warmed up before power is transferred to the gen US 7 356 384 B2 11 erator 436 or 512 at block 676 However if the generator voltage is not above the second preset percentage as deter mined at block 672 the load management control board 144 checks to determine if the utility voltage is above the second preset percentage at block 680 If the utility voltage is not above the second preset percentage as determined at block 680 operation at block 672 is repeated Otherwise if the utility voltage is above the second preset percentage as determined at block 680 the green LED is turned at block 688 the load management control board 144 starts a delay for about 10 seconds to determine if the utility power is stable at block 689 and checks to determine if the delay has elapsed at block 690 Once the load management control board 144 has started the delay before transferring power to the generator 436 512 at block 676 the load management control board 144 checks to determine if the utility voltage is above the second preset percentage at block 684 If the utility voltage is above the second preset percentage as determined at b
26. lied to both the A C unit and the hot water heater Referring back to block 828 if it is determined at block 828 that it is not the first rating check the load management control board 144 checks to determine if the A C unit is about to start at block 860 If the A C unit is about to start as determined at block 860 the load management control board 144 checks to determine if closing the relay 150 will result in the current drawn being less the preset current percentage for example 85 percent at block 864 If it is determined at block 864 that the A C unit is not about to start as determined at block 860 or closing the relay 150 will not result in the current drawn being less the preset current percentage the load management control board 144 repeat edly checks to determine if a time delay for example five minutes has elapsed at block 868 If it is determined at block 868 that the time delay has elapsed the load management control board 144 checks to determine if the current demand is less than the second difference at block 872 as described earlier If it is determined at block 872 that the current demand is not less than the second difference block 860 is repeated Otherwise if the current drawn by the load as determined at block 872 is less than the second difference block 856 is repeated Once the relay 154 is closed or in the CLOSED state the load management control board 144 determines if the relay 150 is in the CLOSED state
27. load management system configured to be powered by a residential generator the residence having a thermostat and an air conditioning system and further hav ing a load unrelated to the air conditioning system the load management system having a first signal responsive switch connectable in circuit between the residential generator and the load the load management system further having a second signal responsive switch connectable in circuit between the thermostat and the air conditioning system the method comprising closing the first signal responsive switch to permit a current from the residential generator to the load receiving a call from the thermostat requesting condi tioned air including receiving the call at the second signal responsive switch interrupting the call with the second signal responsive switch opening the first signal responsive switch to prevent the current from the residential generator to the load based on receiving the call providing the call to the air conditioning system includ ing closing the second signal responsive switch and closing the first signal responsive switch based on the cessation of the call 2 A method as set forth in claim 1 wherein the method further comprises generating a signal and applying the signal to the first signal responsive switch and wherein the closing the first signal responsive switch is in response to the applying the signal 3 A method as set forth in claim 2 where
28. lock 554 block 896 is repeated If closing the relay 150 can not result in the current drawn being less than the preset amount as determined at block 554 block 880 is repeated Referring to FIG 6 which is a continuation of the flow chart 600 of FIG 6e and to block 876 that if the relay 150 is closed the load management control board 144 checks to determine if the current demand is greater than the preset percentage of rated generator current at block 912 If the current demand is greater than the preset percentage of rated generator current as determined at block 912 the load management control board 144 checks to determine if the current demand is greater than the total rated generator current at block 916 Otherwise if the current demand is less than the preset percentage of rated generator current as determined at block 912 the load management control board 144 checks to determine if the A C unit is about to start at block 920 If the A C unit is not about to start as determined at block 920 block 804 is repeated Otherwise if the A C unit is about to start as determined at block 920 block 912 is repeated If it is determined at block 916 that the current demand is greater than the total rated generator current the load management control board 144 opens the relay 154 and records the current difference at block 924 If the current difference is less than the preset amount as determined at block 928 the load management control boa
29. lock 680 or at block 684 the load management control board 144 turns on the green LED at block 688 However if it is determined that the utility voltage is not above the second preset percentage at block 684 the load management control board 144 continues to check if the generator 436 512 warm up time at block 692 has run out If it is determined at block 692 that the warm up time for the generator 436 512 has not run out the load management control board 144 continues or repeats block 684 If it is determined at block 692 that the warm up time has run out the load management control board 144 again checks to determine if the generator voltage is above the second preset percentage at block 696 If it is determined at block 696 that the generator voltage is not above the second preset percentage the load management control board 144 repeats the block 684 Otherwise if it is determined at block 696 that the generator voltage is above the second preset percentage the load management control board 144 opens both of the relays 150 154 for a third preset amount of time at block 700 The load management control board 144 also turns on a red LED at block 700 In some embodiments the third preset amount of time is about five minutes Referring back to block 690 if the delay has not elapsed the load management control board 144 checks to deter mine if the generator 412 536 has warmed up for an amount of time at block 701 If the generator 412
30. me from either the load management control board 144 or the thermostat 158 As described the relays 150 154 are typi cally used to relay power to a load such as the A C 162 and the hot water heater 164 If the relays 150 154 have detected the activating voltage or current signal from the voltage source the relays 150 154 will start examining or detecting a current drawn or power demanded by the connected loads In the example that follows without limitation the relay 150 controls the power being supplied to the A C 162 and the relay 154 controls the power being supplied to the hot water heater 164 Particularly when the relay 150 does not detect any signal during a power outage the relay 150 will remain open However when the relay 150 has detected an activating voltage or current signal from the voltage source such as the thermostat 158 the load management control board 144 can determine if there is enough power capacity to turn on or close the relay 150 to activate the A C 162 If there is not enough power capacity the relay 150 will remain open regardless of the state of relay 154 Furthermore the load management control board 144 will continuously monitor the current in the relay 154 such that the load management control board 144 can determine if opening relay 154 will allow sufficient power to be supplied to the A C 162 by closing relay 150 If there is sufficient power capacity to run the A C 162 the load management cont
31. ments the appropriate amount of time is about five minutes Once the appropriate amount of time has elapsed as determined at block 776 the load management control board 144 checks to determine if the A C unit 412 is about to start at block 780 If the A C unit 412 is about to start as determined at block 780 the load management control board 144 checks to determine if starting the A C unit 412 will result in a total current demand being less than a specific amount for example 85 percent at block 784 In some embodiments the total current demand can be deter mined by adding the current demanded by the A C unit 412 US 7 356 384 B2 13 unit to a difference between the actual current available from the generator 436 and the current demanded by the hot water heater 416 If it is determined at block 784 that the total current demand is less than the preset amount the load management control board 144 checks to determine if the relay 154 is open at block 788 Otherwise if the total current demand is not less than the preset percentage as determined at block 784 or if the A C unit 412 is not about to start the load management control board 144 starts operating at block 828 FIG 6e as discussed below If it is determined that the relay 154 is open at block 788 the load manage ment control board 144 closes the relay 150 at block 792 If it is determined at block 788 that the relay 154 is not open the load management control board 144 car
32. n a high demand appliance is connected to the system while the system is already fully loaded contacts connecting the standby generator to the appliance will remain open until another high demand load is automatically or manually disconnected The operator therefore manually decides the priority of at least some of the loads in the residence In one form the invention provides a load management system for residential use The system includes first and 20 25 30 35 40 45 50 55 60 65 2 second signal responsive switches that are connected to respective first and second loads a sensor that senses first and second electrical signals from the respective first and second loads and a controller The first signal responsive switch has a first priority and the second signal responsive switch has a second priority that is lower than the first priority The controller ensures that the first signal respon sive switch is in a CLOSED state and the second signal responsive switch is in an OPEN state after the sensor has sensed that a combination of the first and second electrical signals exceeds a first threshold value and that the first electrical signal is below a second threshold value In another form the invention provides a method of managing loads for residential use The method includes connecting a first signal responsive switch to a first load and connecting a second signal responsive switch to a second load that
33. ndicators can also be used At block 616 the load management control board 144 checks to see if the generator 436 or 512 needs to be warmed up depending on a jumper setting on the load management control board 144 When the utility power drops below the preset percentage and the jumper settings on the load management control board 144 are set for a specific gen erator warm up the load management control board 144 starts to warm up the generator for a first preset amount of time at block 620 In some embodiments the first preset amount of time is about 20 seconds However if the jumper settings on the load management control board 144 are not set for a specific generator warm up the load management control board 144 starts to warm up the generator 436 512 for an alternate preset amount oftime at block 624 in default In some embodiments the second preset amount of time is about 50 seconds The load management control board 144 checks the fuel switch and jumper settings as indicated in FIG 3 at block 628 Particularly the load management control board 144 checks to determine if the fuel switch and jumper settings are in the LP position at block 628 If the fuel switch settings are in the LP position as determined at block 628 and if the generator rating is 12 KW as determined at block 632 the load management control board 144 presets a power or current rating for the generator 436 512 at about 50 Amps at block 636 If the current ra
34. nditioner 11 A load management system as set forth in claim 7 wherein the first and second signal responsive switches comprise first and second relays respectively
35. nnect For example the emergency load center 520 can be connected to a hot water heater 524 via a contactor 528 For another example the emergency load center 520 can be connected to an air conditioner or an air conditioning unit 532 via a local disconnect 536 The emergency load center 520 can also be connected to other circuits via a plurality of circuit outlets 540 In the embodi ment depicted in FIG 5 the load management control board 144 is installed in the transfer switch 504 However the load management control board 144 can also be imple mented in the emergency load center 520 in some other embodiments FIG 6 includes a flow chart 600 that further illustrates processes that occur in some embodiments including pro cesses that may be carry out by software firmware or hardware At block 604 the load management control board 144 turns on a green light emitting diode LED at block 20 25 30 35 40 45 50 55 60 65 10 604 when the utility power is present The load manage ment control board 144 then sets the contactor 170 of FIG 1 in the utility position at block 608 The load management control board 144 also turns off the green LED when the utility power drops below a preset percentage of the utility voltage at block 612 In some embodiments the preset percentage is about 70 percent when the utility voltage is 240 volts Although the flowchart 600 calls for a green LED other LED s or other i
36. r Specifically the load manage ment control board 144 monitors both incoming generator lines through a pair of current transformers CT s 192 and 194 and determines if there is enough power available to start the air conditioner or other large loads by the generator 112 Depending on the position of a fuel source dip switch for liquid propane or natural gas NG the load management control board 144 can determine that the gen erator 112 is either operating at rated wattage with LP or a reduced wattage with NG as listed in FIG 3 When one of the current transformers CT s 192 194 detects a current reaching or approaching a first percentage amount for example 85 percent or 30 A of rated load capacity the load management control board 144 energizes or opens the relay 150 or 154 In this way the load management control board 144 can start shedding loads based on the lowest priority and advances to the highest priority The priorities are typically fixed at installation with relay 150 or being the last to shed and the first to be added and the relay 154 or hot water heater or other large loads being the first to shed and the last to be added US 7 356 384 B2 5 In some other embodiments the load management con trol board 144 also monitors the current at the relays 150 and 154 demanded by the loads such as the air conditioner 162 and the hot water heater 164 In this way
37. r in Utility position 616 jumper set for No generator warm up 620 624 Yes Generator warm Generator warm up time 20 seconds up time 50 seconds 628 No Is the fuel Switch in LP Yes 632 640 s the Gen rating switch in 15 s the rating switch in 12kw No No 636 644 648 Yes Yes Generator rated Generator rated 50 Generator rated amp 62 5 amp amp 660 s the Gen rating switch in 12kW s the rating switch in 15kW No Generator rated 50 Generator rated Generator rated 40 amp FIG 6 U S Patent Yes No No Apr 8 2008 Sheet 6 of 11 US 7 356 384 B2 Is the Generator voltage above 80 Did the Utility voltage return above 80 of 240 volts Yes Wait warm up time before transferring to Generator 688 Turn On Green LED 689 10 second time delay to determine if Utility is stable Did the Utility voltage return above 80 of 240 volts No Is the generator 690 15 10 second 696 ime delay done Is the Generator voltage above 80 Yes 700 701 generator Turn On Red LED warm up time done 704 708 No 702 Are C T s present No Relays A amp B to Stay open Contactor to stay on Utility 712 Transfer contactor to
38. rd 144 assigns a previously determined current value to the relay 154 at block 932 Otherwise if the current difference is not less than the preset amount as determined at block 928 the load management control board 144 starts a delay for example five minutes at block 936 Thereafter the load management control board 144 repeats block 780 Referring back to block 916 if the current demand is not greater than the total rated generator current the load management control board 144 waits for a preset amount of 0 5 35 40 45 50 65 16 time for example five seconds for the loads to stabilize at block 940 and checks to determine if a delay for example 5 seconds has elapsed at block 944 If the delay has elapsed as determined at block 944 block 924 is repeated Other wise if the delay has not elapsed as determined at block 944 the load management control board 144 checks to deter mine if the A C unit is about to start at block 948 If the A C unit is about to start as determined at block 948 block 912 is repeated Otherwise if the A C unit is not about to start as determined at block 948 the load management control board 144 repeats block 804 Thus the invention provides among other things a load management system Various features and advantages of the invention are set forth in the following claims What is claimed is 1 A method of managing one or more electrical loads of a residence with a
39. re not restricted to physical or mechanical connections or couplings As should also be apparent to one of ordinary skill in the art the systems depicted in the figures are models of what actual systems might be like As noted many ofthe modules and logical structures described are capable of being imple mented in software executed by a microprocessor or a similar device or of being implemented in hardware using a variety of components including for example application specific integrated circuits ASICs Terms like control ler may include or refer to both hardware and or software Furthermore throughout the specification capitalized terms are used Such terms are used to conform to common practices and to help correlate the description with the coding examples equations and or drawings However no specific meaning is implied or should be inferred simply due to the use of capitalization Thus the claims should not be limited to the specific examples or terminology or to any specific hardware or software implementation or combina tion of software or hardware Embodiments of the invention relate to a method and system for managing loads powered by a home or residential generator in an event of utility power outage The system adds and sheds a prioritized load based on the electrical power voltage and current generated by the generator and also based on the electrical power voltage and current demanded by the loads in the re
40. ries out other operations as discussed below If it is determined at block 796 that the current demand is greater than a percentage for example 85 percent of the rated generator current the load management control board 144 continues to check if the current demand is greater than the total rated generator current at block 800 If it is determined at block 800 that the current demand is more than the total rated generator current the load management control board 144 opens the relay 150 and records a current difference between the current drawn when the relay 150 is closed and the current drawn when the relay 150 is open at block 804 However if it is determined at block 800 that the current demand is less than the total rated generator current the load management control board 144 waits for a preset amount of time for example five seconds for the loads to stabilize at block 808 Once the load management control board 144 has waited for the preset amount of time as determined at block 812 the operation in block 804 is repeated Otherwise if the load management control board 144 has not waited for the preset amount of time the load management control board 144 continues to check the current demand at block 796 Referring to FIG 6d which is a continuation of the flow chart 600 of FIG 6c after the relay 150 is open at block 804 the load management control board 144 continues to deter mine the current difference at block 816 Particul
41. rol board 144 will open the relay 154 to disconnect power from the hot water heater 164 and will close the relay 150 to activate the A C 162 US 7 356 384 B2 9 Furthermore after the relay 150 has detected the activat ing signal the power that can potentially be drawn by the load through the relays 150 and 154 is further examined Once the total power that can potentially be drawn by the A C 162 and the hot water heater 164 has been determined the load management control board 144 determines if the available power is enough to power the A C 162 while keeping the relay 154 closed If the power is insufficient for the A C 162 the load management control board 144 will keep the relay 150 open regardless of the status of the relay 154 Still furthermore the load management control board 144 will also be constantly monitoring the current at the relay 154 In this way the load management control board 144 can determine if opening the relay 154 will provide sufficient power to close the relay 150 If the load manage ment control board 144 determines that opening up the relay 154 can provide sufficient power to the A C 162 the relay 154 is opened or turned off When the relay 154 is opened the power is discontinued from the hot water heater 164 and the relay 150 is closed or turned on to provide power to the 162 FIG 4 depicts a second exemplary load management system 400 disposed in the residence of FIG 1 The second exemplary
42. s to shed loads based on a predefined priority from a low priority to a high priority or from a second priority to a first priority which is detailed below A load is shed by simply opening the relay contacts for the load at the respective relays 150 154 and by keeping the relays 150 154 in an OPEN state until the sensed current from the generator 112 is sufficiently below the preset maximum amount When the sensed current has dropped sufficiently the relay 150 154 can be closed and current is supplied from the generator 112 to the loads when a demand signal e g from a thermostat for the load is present Generally the preset maximum amount is 85 percent although other percentages can also be used When the total current drawn drops to a second preset amount of rated load the load management control board 144 will start to add a load based on the higher or the first priority relay 150 first followed by the lower or the second priority relay 154 until the load management control board 144 reaches the preset maximum amount The load management control board 144 continues to operate this way until other situations such as the load management control board 144 switches back from the generator 112 to the utility position arise The second preset amount is generally 60 percent although other per centages can also be used For example when the relay 150 is the first priority relay and is connected to the 162 when the relay 154 is
43. select from a plurality of fuel types such as LP and NG to be provided to the generator 112 Although LP and NG are listed as the fuel types that the operator is to select from other fuel types such as gasoline diesel and the like can also be used depending on the fuel requirements of the generator 112 In this way the load management control board 144 can also be used in a variety of applications to reduce overall manufacturing cost Depending on the fuel type a generator 112 operates either at a rated wattage or at a reduced wattage as described In some embodiments the generator 112 fueled by LP provides more power wattage or current than the same generator 112 fueled by NG Particularly FIG 3 depicts a fuel power table 300 listing a plurality of current amounts generated by differently rated generators fueled by different fuel types The table 300 lists for example that a generator rated at 10 KW fueled by LP produces 41 7 A which is 4 2 A more than the same generator but fueled by NG The load management control board 144 then monitors the incoming lines through the CT s 192 194 based on the settings of the power related switches and the fuel type switches Also the CT s 192 194 typically have the same ratings However the CT s 192 194 can also have different ratings depending on design or user requirements US 7 356 384 B2 7 When the CT s 192 or 194 on any line starts to detect that the current drawn reaches a pre
44. set maximum amount of the rated load the load management system 100 starts to oper ate Controllers for load shedding are well known in the art such as those depicted in U S Pat Nos 4 499 385 4 617 472 6 652 330 and 6 507 164 which are incorporated herein by reference Under utility power from the utility source 116 the load management control board 144 is generally in a sleep mode When the utility source 116 fails to supply power the load management control board 144 enters a power transfer mode in which power is transferred from the utility source 116 to the generator 112 Once in the power transfer mode the load management control board 144 starts to manage and to control the loads that have corresponding relays As described the load management control board 144 monitors both incoming lines from the generator 112 and tries to keep the generator 112 loaded below a preset maximum amount of generator load capacity Depending on which one of the LP and NG switches is set the generator 112 is either operating at rated wattage or at a reduced wattage The load management control board 144 will determine the output power of the generator 112 based on the power rating switch or any preset power rating and the fuel types positions When the CT s 192 194 on any of the power lines from the generator 112 detects that the current generated and drawn reaches the preset maximum current amount the load management control board 144 start
45. sidence In one specific embodiment the system determines the electrical power voltage and current generated by the generator from switch settings monitors the electrical power voltage and current demands from the loads and adds or sheds the loads based on some predetermined parameters 5 20 25 30 35 40 45 50 55 60 65 4 FIG 1 depicts a load management system 100 disposed in a residence embodying the invention The load management system 100 includes a load shed center 104 that is connected to a breaker box or a load distribution panel 108 Power from sources such as a home standby generator or a portable generator 112 and a utility source 116 is connected to a junction box or a transfer switch 120 outside of the resi dence In some embodiments the transfer switch 120 can be installed inside the residence The transfer switch 120 is also connected to the load shed center 104 and the breaker box 108 via a plurality of conduits 124 The operation of the load management system 100 is detailed hereinafter In some embodiments the load management system 100 also includes a load management control board in the trans fer switch 120 Alternatively the load management control board can also be implemented in the load shed center 104 or the breaker box 108 FIG 2 depicts a schematic view of the transfer switch 120 that includes a load management control board 144 which is connected to a thermostat 158 via a
46. tems For example the average resi dence may control a maximum of two high load appliances with the present system Since the present invention is less complicated fewer parts are used which then reduces the cost of manufacturing and the price The systems according to the present invention may also include inexpensive jumpers and or switches that allow for connection with different generators with different ratings and fuel types of these aspects lower the cost for the systems according to the present invention making the systems more appealing and practical for the average resi dence In other words the systems offer flexibility while providing some of the functions that are suitable for average residences at relatively lower costs and are less complicated than expensive commercial load management systems Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description and drawings BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a residential electrical system having a load management system FIG 2 is a system block diagram of the load management system depicted in FIG 1 US 7 356 384 B2 3 FIG 3 is a fuel power table for the load management system depicted in FIG 1 FIG 4 is a second residential electrical system having a load management system FIG 5 is a third residential electrical system having a load management system FIG
47. the priority or the sequence of load shedding and adding can be adjusted based upon the actual demands from the loads For example if the relay 150 is idle or not asking for or demanding any current the load management control board 144 can close the relay 154 In some embodiments the load management control board 144 also controls the transfer switch 120 The transfer switch 120 monitors a utility voltage and determines when the utility power 116 is not present or at a low level when compared with a predetermined threshold For example when the load management control board 144 senses that the generator 112 has been started the load management control board 144 will start to control the current supplied to the loads through the relays 150 154 After the generator 112 is running or operating at a rated speed and voltage for a predetermined amount of time delay the second contactor 170 transfers power from the utility source 116 to the generator 112 Typically the time delay is between 30 seconds and 50 seconds However the time delay may be longer in a colder region in which the generator 112 may take longer to warm up or shorter in a warmer region in which the generator 112 may warm up faster Once the generator 112 is supplying power the load management control board 144 will transfer the generator power to the loads The load management control board 144 checks to ensure that power from the generator 112 is supplied to the loads
48. ting for the generator 436 512 is set in a 15 KW position as determined at block 640 the load management control board 144 then sets the current rating for the generator 436 512 at 62 5 A at block 644 However if the generator 436 512 is not in the 15 KW position or the 12 KW position as determined at block 640 the load management control board 144 sets the generator 436 512 at other amounts of current at block 648 For example the amount of current can be 41 7 A if the generator 436 512 is rated at 10 KW For another example the load management control board 144 can set the current rating for the generator 436 512 at 70 8 A if the generator is rated at 17 KW However if it is determined at block 628 at the fuel switches are not at the LP position the load management control board 144 then checks to determine the fuel switches setting to determine if the setting is at 12 KW at block 652 If the generator rating is set at 12 KW as determined at block 652 the load management control board 144 then sets the current rating of the generator 436 512 at about 40 A at block 656 However if the generator rating is set at 15 KW as determined at block 660 the load management control board 144 sets the current rating at about 50 A at block 664 Otherwise if the generator rating is not set either at 12 KW or at 15 KW the load manage ment control board 144 sets the current rating at other amounts at block 668 As depicted in FIG which
49. ui et al 700 28 4 695 991 A 9 1987 Hudson 4 916 328 A 4 1990 Culp III OTHER PUBLICATIONS 5 422 517 A 6 1995 Verney et al Intellitec 50 AMP Smart Energy Management System Installation 5 923 830 A 7 1999 Fuchs et al and Service Manual P N 5300684B00 Mar 1 2000 6 172 432 B1 1 2001 Schnackenberg et al 307 23 5 Intellitec Powerline Energy Management System Installation and 6 487 509 B1 11 2002 Aisa 702 62 Service Manual P N 5322100A100 at least as early as Mar 22 6 507 164 1 2003 Healey et al 2003 y Ng 6 510 369 Bl 1 2003 Lacy Intellitec Energy Management Unit 2 EMU2 Service Manual 6 590 304 7 2003 Manning et al P N 53 22083A100 at least as early as Mar 22 2003 6 633 802 B2 10 2003 Sodoski et al Generac Power Systems Inc PowerMaster Technical Manual 16 6 652 330 11 2003 Wasilewski ages dated Apr 7 2006 7 010 363 B2 3 2006 Donnelly et al 700 19 P805 A 7 015 599 B2 3 2006 Gull et al cited by examiner US 7 356 384 B2 Sheet 1 of 11 Apr 8 2008 U S Patent b Old mam Er mm HL iE HE HE E ________ i T ILL IEEE E ee HHH AHIHI HHTHH m d ane 1
50. uses the method of managing 51 Int Cl loads for residential use The method includes connecting a G05D 11 00 2006 01 first signal responsive switch to a first load and connecting G05D 17 00 2006 01 a second signal responsive switch to a second load that has G05D 3 12 2006 01 a lower priority than the first load The method also includes G05D 5 00 2006 01 sensing first and second electrical signals from the respec G05D 9 00 2006 01 tive first and second loads and ensuring the first signal G05D 23 00 2006 01 responsive switch is in a CLOSED state and the second 52 U S Cl 700 295 700 286 700 276 signal responsive switch in an OPEN state after both a 700 300 combination of the sensed first and second electrical signals 58 Field of Classification Search 700 205 exceeds a first threshold value and the sensed first electrical 700 287 286 22 28 31 276 278 307 39 361 90 1 See application file for complete search history 172 signal is below a second threshold value 11 Claims 11 Drawing Sheets AIR_CONDITIONER HOT VATCR HEATER POVER 10 HOT VATER HEATER US 7 356 384 B2 Page 2 U S PATENT DOCUMENTS 7 119 457 B1 10 2006 Flegel 307 64 2001 0030468 A1 10 2001 Anderson et al 4 617 472 A 10 1986 Slavik 2002 0024332 Al 2 2002 Gardner 324 103 R 4 620 283 10 1986 Butt et al 2005 0107892 Al 5 2005 Mats
51. vated such that the relay contacts 150 and 154 are opened when the load manage ment control board 144 senses that the utility power from the utility source 116 is not available Alternatively nor mally closed relays could be used and the relays 150 and 154 would open when generator power is available Fur thermore if the load management control board 144 is configured to react to a power outage fast enough the relays 150 and 154 can be configured to be kept closed even when a power outage occurs 20 25 30 35 40 45 50 55 60 65 6 In some embodiments when powered by the generator 112 the load management control board 144 can manage two protected circuits such as the air conditioner 162 and the hot water heater 164 For example the load management control board 144 monitors and records a total amount of current drawn by the loads or appliances applied in the building such that the total amount of current drawn by these loads or appliances is below some limit which may be fixed or adjustable Furthermore the load management control board 144 is generally housed in either a NEMA 1 or NEMA 3R enclosure which is rated for operational temperatures from 32 F to 104 F Although two types of enclosures may be used other enclosures that satisfy other technical requirements can also be used Furthermore the load management control board 144 through the CT s 192 194 monitors the incoming lines and manages the

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