Product User Manual
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1. Product User Manual Models GA1212 Dummy Load Coupler WR340 Document 930071 Rev 1 Gerling Applied Engineering Inc P O Box 580816 Modesto CA 95358 www 2450mhz com Product User Manual Page 2 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 REVISION HISTORY REV DESCRIPTION DATE APPROVAL 1 RELEASE 11JULO3 JFG WARRANTY Products manufactured and sold by Gerling Applied Engineering Inc GAE are warranted to be free of defects in materials and workmanship under normal use and service for a period of twelve 12 months from the date of original shipment GAE s obligation under this warranty is limited to repairing or replacing at GAE s option all non consumable component parts Consumable parts are specifically excluded from this warranty and may include but are not be limited to magnetrons fuses lamps seals o rings v belts and fluids All warranty repairs are to be done at GAE s facility or as otherwise authorized by GAE All shipping charges for warranty repair or replacement are the purchaser s responsibility unless otherwise agreed to by GAE This warranty supercedes all other warranties expressed or implied No warranty is given covering the product for any particular purpose other than as covered by the applicable product specifications GAE assumes no liability in any event for incidental or consequential damages financial losses penaltie2. To ensure safe operation and prevent microwave leakage the equipment must be periodically inspected and maintained as required or recommended 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 4 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 TABLE OF CONTENTS EQUIPMENT DESCRIPTION consista 5 Specifications 5 Outline Drawing 6 INSTALLATION A si obj bw kaka kow w aio 7 Preliminary Inspection 7 Waveguide Configuration 7 Flange Connections 8 Coupler Port Connection 8 Water Flow Requirements 8 Water Fitting Connections 9 Storage and Shipping 9 THEORY OFOPERA TIO Nicosia o a ia ada a a adai D A ik a 10 Basic Operation 10 Performance Considerations 10 USER MAINTENANCE AND REPAIIR ccccceeeeeeeeeseceeensssseeeeeeseeeeeeeesseeeeeeeeseaaaes 12 Insert Block Replacement Procedure 12 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 5 Models GA1212 Dummy Load Coupler WR340 EQUIPMENT DESCRIPTION 930071 Rev 1 Specifications 2003 Gerling Applied Engineering Inc The model GA1212 Dummy Load Coupler is designed for dual purpose use in high power microwave networks Primarily it is a means to dissipate up to 6kW of microwave power that is not being utilized for other purposes Additionally this load provides a convenient means to measure the level of incident microwave power using common microwave power me
3. results in a detuning of the load impedance and a decrease in energy absorption 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 11 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 TYPICAL PERFORMANCE 2450 MHz Return Loss dB AA i 20 25 30 40 50 60 70 80 90 100 110 120 Inlet Water Temp degrees F Figure 3 Return loss vs inlet water temperature 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 12 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 USER MAINTENANCE AND REPAIR The GA1212 dummy load coupler is designed to be maintenance free and does not require any user maintenance under normal operating conditions However the dummy load couplers can sustain damage if the water flow rate is insufficient to prevent vaporization boiling while operating under conditions of high incident microwave power In the event of damage due to insufficient or lack of water flow the dummy load coupler can be repaired by replacing the polyethylene insert block Repair kit model GA8105 available from GAE includes all necessary components for replacement of the insert block However please note that changing the insert block can alter the calibration of the coupler port For this reason we strongly recommend that the dummy load coupler be returned to GAE for repair and recalibration Inser
4. 1 50 E 1 00 ers y 3 0 50 Se s gt ME a oo EEE e ee 2 40 60 80 100 120 140 Inlet Water Temp F Figure 2 Recommended minimum water flow rates for given inlet water temperature and incident microwave power level Water Fitting Connections Standard 1 8 NPT female fittings are provided at the end of the dummy load coupler opposite the waveguide flange The source of water can be connected to either fitting It is recommended that a thread sealant such as Teflon pipe thread tape be used to ensure a leak free connection Care should be taken to prevent debris from falling into the fitting holes Storage and Shipping Upon removing the dummy load coupler from the set up it is recommended that all water be drained prior to storage or shipping This precaution will prevent damage in the event that freezing temperatures are encountered during storage or shipping 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 10 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 THEORY OF OPERATION Basic Operation The GA1212 dummy load coupler utilizes water as the medium for absorbing microwave energy that enters through the waveguide flange The internal UHMW polyethylene block through which the water flows is transparent to microwave energy referred to as having low dielectric loss characteristics and allows the energy to be absorbed directly into the water The dielectric l
5. IRCUIT TERMINATION Figure 1 Typical waveguide configuration using dummy load coupler to absorb and measure reflected microwave power 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 8 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 Flange Connections The waveguide flange of the dummy load coupler must be properly connected to another waveguide component having a similar flange style Bolts and nuts must be installed at all flange bolt holes and tightened securely prior to operation Microwave Leakage Regulatory limits for microwave leakage Ca relate to standards for human safety and interference with other electronic devices Standards for human safety as adopted by OSHA the International Electrotechnical Commission IEC and other regulatory agencies limit leakage to 5 mW cm measured at 5 cm from the leakage source under normal operating conditions and 10 mW cm at 5 cm from the source under abnormal operating conditions The U S Federal Communications Commission FCC has established regulations limiting the emission of energy at frequencies outside the ISM bands All GAE waveguide components meets these requirements when properly connected to another waveguide component Coupler Port Connection The coupler port is a standard 50 Ohm Type N female connector which is compatible with Type N male connectors common to most commercially available detector diodes and power sensors
6. T FEMALE TYPE N FEMALE La 4 75 121 5 44 138 1 1 10 28 Po o d ap di l olo O 1 86 47 O 3 75 95 O O 2X 9 250 96 4 O O O FLANGE ALIGNMENT HOLES 1 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 7 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 INSTALLATION Preliminary Inspection Upon arrival at the installation site the dummy load should be thoroughly inspected for damage or wear caused during shipping Any visible damage to the packaging material or dummy load coupler should be noted and reported immediately to the shipping company in accordance with standard claims procedures The following components are included a Dummy Load Coupler b Product User Manual Waveguide Configuration The dummy load coupler can be connected to and used with any common waveguide component having a compatible flange The mounting position can be in any orientation Figure 1 below illustrates a common dual purpose configuration in which the dummy load coupler is used to both absorb and measure microwave power reflected from the process load This configuration eliminates the need for a separate waveguide directional coupler MICROWAVE GENERATOR DUMMY LOAD COUPLER APPLICATOR CIRCULATO SHORT C
7. The coupling factor is nominally 60 dB unless specified otherwise thus limiting the output signal to 6 milliwatts which is well within the rating of most detection devices Ensure that the mating connector is tightened securely by hand do NOT use tools to tighten Water Flow Requirements A source of water must be connected to the dummy load coupler that provides an adequate rate of flow The nominal water flow rate is 1 0 gom However the flow rate must be maintained such that the outlet water temperature does not exceed 140 F The minimum allowable flow rate depends on the level of incident microwave power and the inlet water temperature Figure 2 below shows the minimum flow rate vs incident microwave power and inlet water temperature CAUTION Failure to provide an adequate rate of water flow A can result in severe damage to the dummy load coupler It is strongly recommended that an interlock device such as an in line water flow switch be used to prevent operation of the microwave generator in the event of inadequate or loss of water flow 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 9 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 MINIMUM WATER FLOW RATES 4 50 o 4 00 gt 6 0 kW Go 3 50 3 0 kw ki 3 00 2 0 kW 2 E 2 50 1 0 kw 200 0 5 kW Fi A E
8. of the dummy load coupler Carefully slide the insert block assembly into the dummy load coupler waveguide Ensure that the two plugs with smaller o rings on the sides of the block are fully inserted into the counter bore holes CAUTION If the plugs have come out as may happen during shipping ease them back in while being careful to avoid nicking the o rings on the edge of the counter bore Insert the two 14 20 socket head screws into the counter bored holes at the end of the waveguide and engage the screw threads into the insert block Carefully tighten the screws with the hex driver just enough to compress the o rings CAUTION Over tightening the screws will cause the Helicoil inserts inside the block to become loose and may result in permanent damage to the insert block Install water fittings apply water pressure 70 psi max and check for water leaks Reinstall the matching stub making sure that it is located in its original position marked earlier during disassembly Reinstall dummy load coupler into waveguide set up MATCHING STUB MOUNTING HARDWARE NS SMALL O RING PLUG MATCHING a ae 1 4 20 SOCKET HEAD SCREW INSERT BLOCK LARGE O RING or ET LOAD WAVEGUIDE ITEMS INCLUDED WITH GA8105 INSERT REPAIR KIT Figure 4 Exploded view of dummy load coupler assembly 2003 Gerling Applied Engineering Inc Modesto CA
9. oss of water is relatively high and is capable of absorbing over 99 of the incident microwave energy Performance Considerations In order to absorb substantially all of the incident microwave energy the characteristic impedance of the dummy load coupler must be a close match to that of the waveguide to which it is connected The factors that influence this impedance match include the microwave frequency the dielectric properties of the insert block and the water and the physical geometry of the block and the channels through which the water flows The dielectric properties of most materials vary with changes in temperature In the case of water an increase in temperature causes a decrease in its dielectric loss and in general results in a decrease in microwave energy absorption However the geometry of the absorbing load can be optimized or tuned for the dielectric properties at a desired temperature In this case energy absorption is maximized at the design temperature and is reduced at both higher and lower temperatures As shown in Figure 3 below the dummy load coupler is designed for optimal performance at inlet water temperatures between 75 F 24 C and 85 F 29 C For best performance the outlet water temperature should remain as close as possible to the inlet temperature A low water flow rate and high incident power causes a large increase in temperature which since the heated water is still inside the load
10. s or other losses incurred in conjunction with the use of GAE products DOCUMENT CONVENTIONS NOTE Means the reader should take note Notes contain helpful information suggestions or references to other sections chapters or documents CAUTION Means the reader should be careful You are doing something that might result in equipment damage or loss of data WARNING Means danger A situation exists that could cause bodily injury or death All personnel must be aware of the hazards involved with high voltage electrical circuitry and high power microwave devices gt gt 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 3 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 WARNING All waveguide dummy loads manufactured by GAE are intended for use with other equipment capable of producing a microwave field that is potentially hazardous to operating personnel It must never be connected or operated in a manner that allows a field in excess of 10 milliwatts per square centimeter to be generated in an area accessible to operating personnel Contact GAE Inc for technical support prior to installation and or operation of this unit if there is any question or concern about microwave leakage All waveguide flange and electrical cable connections throughout the system must be secure prior to operation Never operate the microwave generator without a properly rated absorbing load attached
11. t Block Replacement Procedure 1 1 1 2 1 3 Equipment Requirements Hex Allen driver 3 16 Disassembly 1 2 1 1 2 2 1 2 3 1 2 4 1 2 5 WARNING Turn off microwave power and disconnect line power from the microwave generator before disconnecting any waveguide components Disconnect the water supply and drain from the water fitting connections at the back of the dummy load coupler Remove the dummy load coupler from the waveguide set up and drain the water from inside the load Note the position of the Matching Stub mounting hardware by marking the waveguide surface Loosen the stub mounting screw and remove the stub Remove the two socket head screws at the back of the dummy load coupler Insert the hex driver into one of the two screw holes and gently push the insert block out of the dummy load coupler waveguide Reassembly 1 3 1 Inspect the inside of the waveguide for signs of damage and or corrosion In particular carefully inspect the four o rings seats on the inside of the 2003 Gerling Applied Engineering Inc Modesto CA Product User Manual Page 13 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 1 3 2 1 3 3 1 3 4 1 3 5 1 3 6 1 3 7 back wall Additional repairs may be required in the event of internal damage or excess corrosion Remove the four greased o rings from the polyethylene bag and place them into each of the four seats on the inside back wall
12. ters The compact design and high reliability of this load makes it ideal for a variety of uses Typical applications include magnetron isolation from reflected power when used with a 3 port circulator high power test stations and variable Q applicators Microwave power delivered to the dummy load is absorbed by water which internally flows through channels in a solid UHMW polyethylene block Naval brass is used for all water fitting connections to minimize corrosion The waveguide body is fabricated with dip brazed aluminum A non directional coupling probe senses the internal electric field strength and delivers the signal through a Type N female connector Waveguide Flange Frequency Incident Power Return Loss Coupler Port Coupling Factor Water Connections Water Flow Water Pressure Water Temp Net Weight WR340 UG554 U 2450 MHz nominal Up to 6kW continuous 20 dB min 2450 MHz 75 85 F inlet water Type N Female 50 Ohm 60 dB 1 dB nominal 2450 MHz 75 85 F inlet water 1 8 NPT female 1 0 gpm nominal 4 0 gom maximum 70 psi maximum Inlet 40 F 4 C minimum Outlet 140 F 60 C maximum 1 5 Ib 3 3 kgm Modesto CA Product User Manual Page 6 Models GA1212 Dummy Load Coupler WR340 930071 Rev 1 Outline Drawing 1 00 25 l 1 78 45 y 3 56 90 10X 6 265 96 7 FLANGE BOLT HOLES Y 2X WATER CONNECTIONS ou OUTPUT FLANGE F 1 8 NP
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