A flooded motor can sometimes be saved, but that has to be established by measurement, not by eye. The first rule is not to run the motor until you are sure it is dry; applying voltage to a wet winding can genuinely burn out a motor that could have been saved.

DRG-132S1-2 5.5 kW 3000 rpm cast iron frame DRG three-phase motor – flooded motor

The type of water changes the decision

Clean rainwater and muddy floodwater are not the same. Mud and fine silt settle between the windings, in the bearings and in the terminal box, and once dry they can leave a conductive layer. Seawater and water carrying fertiliser or chemicals speed up corrosion. Motors briefly wetted by clean water have a good chance of repair; where mud or salt water is involved, replacement is chosen more often.

Recovery procedure

  1. The supply is isolated and the motor disconnected from the panel.
  2. The terminal box is opened and water and mud inside are cleaned out.
  3. If needed, the motor is dismantled in a workshop; the winding is cleaned and dried at a controlled temperature.
  4. Bearings and grease are checked; a bearing that has taken in water is usually renewed.
  5. Qualified electrical staff carry out an insulation test. The result and the acceptance criterion are for them to judge.

When is buying a new one the better option?

  • If insulation values do not reach an acceptable level after drying
  • If there is rust, cracked varnish or mud residue in the winding
  • If the motor is small and the repair cost approaches that of a new motor
  • If the machine is critical and the drying time cannot be waited out

Where to put the new motor

IP55 protects against water jets, not against being under water. In basements, well heads or pump rooms beside a stream where flooding is a risk, moving the motor onto a raised base may save it next time. Applications that must run under water need a submersible motor; that product is not in the DRG standard range. As water and moisture damage fall outside the warranty, the choice of location matters all the more.

For pump rooms, see application examples on the pump motors page and compare models with the same power and speed as the old motor in the shop.