Celebrating 65 Years of "No Problem" Service


Blog posts of '2023' 'March'

Thermal Motor Protection

Most quality sump, effluent, and sewage pumps are equipped with thermal overload protection. When excessive heat is detected, the motor shuts down automatically and restarts one the motor cools. Overloads are already built into smaller motors, while larger motors have electronic overloads in the control panel that usually protect from phase loss as well.

Some common causes of overheating or overloading include:

  • Voltage unbalance
  • Jammed or locked impeller
  • Improper float switch setting
  • Continuous operation of the pump
  • Running dry (most submersible pumps)
  • Faulty windings

In a single-phase pump, the winding overload protector operates on the combined effect of temperature and current. This means the overload protector will trip out and shut the motor down if the windings become too hot or the load current passing through them becomes too high. It will then automatically reset and restart the pump after the motor cools to a safe temperature.

However, repeated motor overheating and shutdowns require a deep dive into the problem. Things to check are…

  • the resistance of the motor windings.
  • blockage of the impellers, which will need to be cleared if obstructed.
  • the bearings, which will need to be replaced if not in good working order.
  • if the pump is wired to the correct voltage.

If something is not done to remedy the overload situation, the overload will continue to trip and reset itself until the motor is destroyed.

If you need assistance to troubleshoot the cause of overheating, we can help you with our “No Problem” Service. Contact “Your Partners in Pumping” at 262-253-1353 or sales@jmipumps.com.