Three-Phase Motors - Franklin Electric
Contents
1. E MOTOR APPLICATION Reduced Voltage Starters All Franklin three phase submersible motors are suitable for full voltage starting Under this condition the motor speed goes from zero to full speed within a half second or less The motor current goes from zero to locked rotor amps then drops to running amps at full speed This may dim lights cause momentary voltage dips to other electrical equipment and shock power distribution transformers In some cases the power companies may require reduced voltage starters to limit this voltage dip There are also times when reduced voltage starters may be desirable to reduce motor starting torque thus reducing the stress on shafts couplings and discharge piping Reduced voltage starters also slow the rapid acceleration of the water on start up to help control upthrust and water hammer Reduced voltage starters may not be required if the maximum recommended cable length is used With maximum recommended cable length there is a 5 voltage drop in the cable at running amps resulting in about 20 reduction in starting current and about 36 reduction in starting torque compared to having rated voltage at the motor This may be enough reduction in starting current so that reduced voltage starters are not required Three Lead Motors Autotransformer or solid state reduced voltage starters may be used for soft starting standard three phase motors When autotransformer starters are used the motor shoul2. 6A 52 100A 68A 136A 92A 6 LEAD Y A 69A 48A 97A 69A 132A 90A 173A 18A 236A 159A 76A 55A 1A 76A 145A 104A 194A 132A 263A 180A 6 LEAD Y A 114A 80A 133A OIA 188A BOA 265A 181A 337A 232A Based on 30 C maximum ambient with cable length of 100 feet or less Continued on next page 38 Three Phase Motors MOTOR APPLICATION E Inline Booster Pump Systems Continued Four Continuous Monitoring System Requirements for Sealed Booster Systems 39 Water Temperature Feed water on each booster must be continuously monitored and not allowed to exceed the motor nameplate maximum ambient temperature at any time IF THE INLET TEMPERATURE EXCEEDS THE MOTOR NAMEPLATE MAXIMUM AMBIENT TEMPERATURE THE SYSTEM MUST SHUTDOWN IMMEDIATELY TO PREVENT PERMANENT MOTOR DAMAGE If feed water temperatures are expected to be above the allowable temperature the motor must be derated See Franklin s AIM manual Hot Water Applications section for derating guidelines The high temperature feed water derating is in addition to the exchange to DI water derating if the motor factory fill solution was exchanged to DI water Inlet Pressure The inlet pressure on each booster module must be continuously monitored It must always be positive and higher than the NPSHR Net Positive Suction Head Requirement of the pump A minimum of 20 PSIG 1 38 Bar is required at all times except for 10 seconds or less when the motor is starting and the system i
3. applied per the below guidelines However they will be more sensitive to application variances than the other two designs All of the above motors must be applied per the guidelines listed below In addition for all applications where the motor is applied in a sealed system a Submersible Motor Booster Installation Record Form 3655 or its equivalent must be completed at Start up and received by Franklin Electric within 60 days A sealed system is one where the motor and pump intake are mounted in a sleeve and the water feeding the pump intake is not open to the atmosphere 56 Three Phase Motors Wd Motor APPLICATION Inline Booster Pump Systems Continued Design And Operational Requirements Derating Factor for Motors That Must Have Their Factory Fill Replaced With Deionized Water 8 Encapsulated Motor Non Vertical Operation Vertical Shaft up 0 to Horizontal 90 operation is acceptable as long as the pump transmits down thrust to the motor within 5 seconds after start up and continuously during operation However it is best practice to provide a positive slope whenever it is possible even if it is only a few degrees 2 Motor Sleeve and Pump Support System The booster sleeve ID must be sized according to the motor cooling and pump NPSHR requirements The support system must support the motor s weight prevent motor rotation and keep the motor and pump aligned The support syst
4. the pump load multiplier number indicated on the vertical axis to determine the Minimum Motor Nameplate Rating 5 Motor and Pump Alignment The maximum allowable misalignment between the Fourth Select a motor with a nameplate equal or higher than the above calculated value motor pump and pump discharge is 0 025 inch per 12 inches of length 2 mm per 1000 mm of length This must be measured in both directions along the assembly using the motor pump flange connection as the starting point The booster sleeve and support system must be rigid enough to maintain this alignment during assembly shipping operation and maintenance 7 Motor Alterations Sand Slinger amp Check Valve Plug On 6 and 8 motors the rubber sand slinger located on the shaft must be removed If a pipe plug is covering the check valve it must be removed The special Booster motor already has these modifications 6 Lubrication and Heat Resistance The best motor lubrication and heat resistance is obtained with the factory based propylene glycol fill solution Only when an application MUST HAVE deionized DI water should the factory fill solution be replaced When a deionized water fill is required the motor must be derated as 8 Frequency of Starts Fewer than 10 starts per 24 hour period are recommended Allow at least 20 minutes between shutdown and start up of the motor indicated on the below chart The exchange of the motor fill solution to DI water 9 Control
5. d be supplied with at least 55 Of rated voltage to ensure adequate starting torque Most autotransformer starters have 65 and 80 taps Setting the taps on these starters depends on the percentage of the maximum allowable cable length used in the system If the cable length is less than 50 of the maximum allowable either the 65 or the 80 taps may be used When the cable length is more than 50 of allowable the 80 tap should be used Inline Booster Pump Systems Franklin Electric offers three different types of motors for non vertical applications The Booster motors are specifically designed for booster applications They are the Best Choice for sealed Reverse Osmosis applications These motors are the result of two years of focused development and bring additional value and durability to booster module systems These motors are only available to OEMs or Distributors who have demonstrated capability in Booster Module systems design and operation and adhere to Franklin s Application Manual requirements 2 The Hi Temp motors have many of the internal design features of the Booster motor It s additional length allows for higher temperature handling and the Sand Fighter sealing system provides greater abrasion resistance One or both of these conditions are often experienced in open atmosphere applications such as lakes ponds etc Continued on next page Three Phase Motors Six Lead Motors Wye Delta starters are us
6. ed with six lead Wye Delta motors All Franklin 6 and 8 three phase motors are available in six lead Wye Delta construction Consult the factory for details and availability Part winding starters are not compatible with Franklin Electric submersible motors and should not be used Wye Delta starters of the open transition type which momentarily interrupt power during the starting cycle are not recommended Closed transition starters have no interruption of power during the start cycle and can be used with satisfactory results Reduced voltage starters have adjustable settings for acceleration ramp time typically preset at 30 seconds They must be adjusted so the motor is at full voltage within THREE SECONDS MAXIMUM to prevent excessive radial and thrust bearing wear If Subtrol Plus or SubMonitor is used the acceleration time must be set to TWO SECONDS MAXIMUM due to the 3 second reaction time of the Subtrol Plus or SubMonitor Solid state starters AKA soft starts may not be compatible with Subtrol Plus SubMonitor However in some cases a bypass contactor has been used Consult the factory for details During shutdown Franklin Electric s recommendation is for the power to be removed allowing the pump motor to coast down Stopping the motor by ramping down the voltage is possible but should be limited to three 3 seconds maximum 5 The Standard Vertical Water Well 40 125 hp motors can be adapted to non vertical applications when
7. em must also allow for thermal axial expansion of 1 00 Service Factor 50Hz i 2 Q D fo al Q E a the motor without creating binding forces 05 115 Service Factor 60Hz 35 30 25 20 5 Motor Support Points A minimum of two support points are required on the Feed Water Temperature C motor One in the motor pump flange connection area and one in the bottom end of the motor area The motor castings not the shell area are recommended as FIG 9 support points If the support is a full length support and or has bands in the shell area they must not restrict heat transfer or deform the shell First Determine maximum Feed Water Temperature that will be experienced in this application If the feed water exceeds the maximum ambient of the motor both 4 Motor Support Material and Design The support system shall not create any areas Mie eee EE ETN eno WaIE C OSIM MUSH AN of cavitation or other areas of reduced flow less than the minimum rate required Second Determine the Pump Load Multiplier from the appropriate Service Factor curve by this manual They should also be designed to minimize turbulence and vibration Typical 1 15 Service Factor is for 60 Hz ratings amp 1 00 Service Factor for and provide stable alignment The support materials and locations must not inhibit 50 Hz ratings the heat transfer away from the motor Third Multiply the Pump Load Requirement times
8. ing Soft Starters with a SubMonitor require a start up bypass h consult the factory for details SubMonitor can not be used in applications using a VFD control 11 Motor Surge Protection Properly sized grounded and dedicated motor surge arrestors must be installed in the supply line of the booster module as close to the motor as possible This is required on all systems including those using Soft starters and variable speed drives inverter drives 12 Wiring Franklin s lead assemblies are only sized for submerged operation in water to the motor nameplate maximum ambient temperature and may overheat and cause failure or serious injury if operated in air Any wiring not submerged must meet applicable national and local wiring codes and Franklin Cable Chart Tables 16 21 Notice wire size wire rating and insulation temperature rating must be known when determining its suitability to operate in air or conduit Typically for a given size and rating as the 17 insulation temperature rating increases its ability to operate in air or conduit also increases 13 Check Valves Spring loaded check valves must be used on start up to minimize motor upthrusting water hammer or in multiple booster parallel applications to prevent reverse flow Table 38 Franklin Cable Chart See item 12 Wiring above 10 AWG 8 AWG 6 AWG NAMEPLATE RATED 7 7 AMPSFULLLOAD INAR conn NAR f conpu NAR conpur Pressure Relief Valves A pressu
9. re relief valve is required and must be selected to ensure that as the pump approaches shut off it never reaches the point that the motor will not have adequate cooling flow past it System Purge Can Flooding An air bleeder valve must be installed on the booster sleeve so that flooding may be accomplished prior to booster start up Once flooding is complete the booster should be started and brought up to operating pressure as quickly as possible to minimize the duration of an upthrust condition At no time should air be allowed to gather in the booster sleeve because this will prevent proper cooling of the motor and permanently damage it System Flush Must Not Spin Pump Applications may utilize a low flow flushing operation Flow through the booster sleeve must not spin the pump impellers and the motor shaft If spinning takes place the bearing system will be permanently damaged and the motor life shortened Consult the booster pump manufacturer for maximum flow rate through the pump when the motor is not energized Open Atmosphere Booster Pump Systems When an open booster is placed in a lake tank etc that is open to atmospheric pressure the water level must provide sufficient head pressure to allow the pump to operate above its NPSHR requirement at all times and all seasons Adequate inlet pressure must be provided prior to booster start up 4 AWG 2 AWG IN IN INAIR conpum NAIR conpurr 3 LEAD DOL 40A 28A 56A 40A
10. s Soft Starters and VFDs Reduced voltage starters and variable speed must be done by an approved Franklin service shop or representative using a drives inverter drives may be used with Franklin three phase submersible vacuum fill system per Franklin s Motor Service Manual instruction The motor shell motors to reduce starting current upthrust and mechanical stress during start up then must be permanently stamped with a DI closely behind the Serial Number The guidelines for their use with submersible motors are different than with normal air cooled motor applications Refer to the Franklin Electric Application The maximum pressure that can be applied to the motor internal components Installation and Maintenance AIM manual Reduced Voltage Starters section or during the removal of the factory fill solution is 7 psi 0 5 bar Variable Speed Submersible Pump Operation Inverter Drives sections for specific details including required filtering Continued on next page 3 Wd Motor APPLICATION Inline Booster Pump Systems Continued 10 Motor Overload Protection Submersible motors require properly sized ambient 14 compensated Class 10 quick trip overloads per Franklin s AIM manual guidelines to protect the motor Class 20 or higher overloads are NOT acceptable Franklin s SubMonitor is strongly recommended for all large submersibles since it is capable of sensing motor heat without any additional wiring to the motor Applications us
11. s coming up to pressure Even during these 10 seconds the pressure must remain positive and be higher than the NPSHR Net Positive Suction Head Requirement of the pump PSIG is the actual value displayed on a pressure gauge in the system piping PSIG is the pressure above the atmospheric conditions If at any time these pressure requirements are not being met the motor must be de energized immediately to prevent permanent damage to the motor Once the motor is damaged it is usually not immediately noticeable but progresses and results in a premature motor failure weeks or months after the damage occurred Motors that will be exposed to pressure in excess of 500 psi 54 47 Bar must undergo special high pressure testing Consult factory for details and availability Discharge Flow The flow rate for each pump must not be allowed to drop below the motor minimum cooling flow requirement IF THE MOTOR MINIMUM COOLING FLOW REQUIREMENT IS NOT BEING MET FOR MORE THAN 10 SECONDS THE SYSTEM MUST BE SHUT DOWN IMMEDIATELY TO PREVENT PERMANENT MOTOR DAMAGE Discharge Pressure The discharge pressure must be monitored to ensure that a downthrust load toward the motor is present within 3 seconds after start up and continuously during operation IF THE MOTOR DISCHARGE PRESSURE IS NOT ADEQUATE TO MEET THIS REQUIREMENT THE SYSTEM MUST BE SHUT DOWN IMMEDIATELY TO PREVENT PERMANENT MOTOR DAMAGE
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