Current sensitive thermal protectors are more and more widely used to the applications that need both over heat and over load protections. For examples, all electrical motor driven window lifts, wipers and skylights; some appliances like juicers, blenders and grinders. When the motors are stuck, the current flowing through the windings would rise rapidly. To prevent the motors from overheating or loading, the current sensitive thermal protector need to be equipped. The common trip off time for a current sensitive thermal protector is 4~10 seconds under overloading current. Of course, other options for trip off time are also possible according to the users’ requirements.
Normally there are two ways of testing the protector.
One is simulation test. That’s easy. You only need to use a constant current power supply and connect the protector to the power supply. Then, you can see in how many seconds the protector would trip.
The other one is mock-up test. Before connecting to main power, you need to connect the protector to your motor and lock the rotor. Then, close the main power. If the parameters of thermal protectors are set correctly, it would cut the circuit off in prescribed period, like 4~10 seconds. The first trip off time would be longer. After the initial 1 or 2 cycles, the trip off time in the next 20 cycle should be almost same and inside of the tolerance. If the thermal protector can not cut the circuit off until 20 or 30 seconds, it means the parameters of thermal protector are not correct. The operator needs to stop the test immediately to avoid burning the application.
Comparing to pure temperature sensitive thermal protector, the current sensitive protector has no specific requirement of contact surface when mounting to the application.
We now have two models of current sensitive thermal protector for your option. TS series and 3MPE series.