Why protect motors?
Overheating of motor insulation causes reduction in dieletric strength which can result in motor insulation damage or failure. The following
are causes of motor overheating for which Klixon motor portectors can be applied to achieve protection:
Prolonged running overload
Locked rotor–mechanical / electrical failure to start
Low line voltage
High ambient temperature and lack of ventilation
Klixon phenolic motor protectors are equipped with a bimetallic snap–acting disc, on which the contacts are mounted, and through which the current flows.
If overheating conditions occur, the heating effect of the current flow through the Klixon disc and the infulence of motor heat will cause the disc temperature to rise.
When the disc reaches the calibrated setpoint, the Klixon protector automatically opens and shuts down the motor, limiting the winding and shell temperature.
When the motor has cooled to an acceptable operating level, allowing the protector to cool to its reset temperature, the Klixon protector resets automatically to a closed contact position allowing the motor to restart.
Manual reset versions are also available for applications where automatic restarting may be hazardous to equipment or operations.