9.
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Controls-Soft Starters and VFDs: Reduced voltage starters and variable speed drives (inverter drives) may be used with Franklin three-phase submersible motors to reduce starting current, upthust, and mechanical stress during start-up. The guidelines for their use with submersible motors are different than with normal air cooled motor applications. Refer to the Franklin Electric Application, Installation and Maintenance (AIM) Manual Reduced Voltage Starters section or Variable Speed Submersible Pump Operation, Inverter Drives sections for specific details including required filtering.
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10.
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Motor Overload Protection: Submersible motors require properly sized ambient 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 using Soft Starters with a SubMonitor require a start-up bypass - consult the factory for details. SubMonitor can not be used in applications using a VFD control. |
11.
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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).
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12.
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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 Table 24. (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 insulation temperature rating increases, its ability to operate in air or conduit also increases.)
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13.
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Check Valves: Spring-loaded check valves must be used on start-up to minimize motor upthusting, water hammer, or in multiple booster (parallel) applications to prevent reverse flow.
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14.
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Pressure Relief Valves: A pressure 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. |
15.
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System Purge (Can Flooding): An air bleeder valve must be installed on the booster sleeve so that flooding may be accomplished prior to booster startup. Once fl ooding is complete, the booster should be started and brought up to operating pressure as quickly as possible to minimize the duration of an upthust 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.
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16.
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System Flush – Must Not Spin Pump: Applications may utilize a low flow flushing operation. Flow though 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 though the pump when the motor is not energized.
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Table 37 Franklin cable chart (see 12 Wiring)
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Based on 30 °C maximum ambient with cable length of 100
feet or less. |
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