Franklin Electric Single-Phasing / Voltage Imbalance (3‑phase systems)

Pump motor is extremely loud with a low-frequency hum and vibration, especially on startup

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

One phase open at Franklin Electric motor terminals, Loose or burned contactor pole, Blown fuse on one phase, Internal motor winding open

Safety first: Lock out and tag out power before working on 3‑phase circuits.

Check fuses and contactor: Inspect and test all three fuses and contactor poles feeding the pump. Replace any failed components.
Measure phase voltages: Confirm balanced voltage on all three phases at the motor terminals.
Test motor windings: Measure resistance between each pair of motor leads. Significant imbalance indicates a winding fault; replace the motor.
Do not run single-phased: Do not operate the pump until all three phases are restored to prevent motor damage.

Professional Required 5/5

Franklin Electric pump motor

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