A submersible pump works within its own liquid environment which is why it is necessary to provide built in motor protection. Tsurumi has built in motor protection in all of its submersible pumps.
Located directly above the motor windings, a0-00 snap-action self-resetting bi-metal device cuts off voltage from all three phase windings simultaneously if the current is too large in one, two or all three windings, or if the windings get too hot.
Tsurumi enables measurement of winding resistance and insulation from the far end of the cable, without ever removing the cover from the motor in the field.
A built-in thermal motor protection device reacts to the heat caused by overcurrent or run-dry conditions. It not only cuts off the motor circuit automatically but also resets by itself. When the motor cools down to a safe operating temperature, the motor restarts.
1: Protects the pump from overheating
2: Cuts off voltage supply if overheating or excess voltage is detected
3: Motor restarts when the motor cools to a safe operating temperature