Thermostat

In the canned Motor Pump, the motor is cooled by the pumped fluid itself. Therefore suitable insulation class depending on the temperature of the liquid handled is chosen. Occasionally the motor winding temperature may exceed limits particularly due to some malfunction of the cooling system. As a precaution from damage of the motor a thermostat is embedded in the hot spot of the winding to protect the motor from over heating. Thermostat is usually of th closed contact type which will open out at the precautionary preset temperature causing the motor protection circuit to trip off the motor. Thermostats are installed with the motor of Canned Motor Pump, as a standard feature.

Temperature Monitors

Thermowells /thermocouples are installed in the construction for measurement of fluid temperature. This enables switching of the pump assembly if the temperature crosses acceptable limits, preventing excessive damage to the pump.

Dry Run Protection

It is a low current sensing device, to protect the pump from cavitations condition when the suction flow drops to unsafe levels. This protective device automatically trips off the pump avoiding any damages. The fall in section flow may be due to the following reasons:

• Choking of strainer.
• Unforeseen closure of suction and discharge valve.
• Suction flow affected by vapour lock and available NPSH at any point of time.

Inducer

Inducers are axial Impellers, which are installed closely in front of the first impellers of a Centrifugal Pump on the same shaft. The inducers cause an additional static pressure in front of the impeller. They are particularly used where the NPSHA is not sufficient, in order to reduce the NPSHR value of the pump.