Products containing various motors, such as shaded pole motors, permanent split capacitor motor, fractional horsepower motors, used for vacuum cleaners, washing machines, air conditioners, kitchen electrical appliances, other electrical home appliances;  water pumps, crusher, mixer, mowing machine, snowsweeper and other construction or gardening tools; car window lift motor, sunroof motor, rain wiper motor, sliding door motor, actuator motor, and other automobile accessories; 

Coils, transformer, solenoid, fluorescent ballasts, LED drivers, power switches, 

Rechargeable battery packs, PCB, integrated circuit, 

Electrical heating devices, such as electrical water heater, electrical cooker, coffee pot, induction cooker, car seat heater, fire place, etc.

 

A thermal protector is placed internallly within a motor or motor-compressor to protect the motor and motor windings components from dangerous overheating that can cause motor failure.

 

This overheating generally occurs when the motor is overloaded, a bearing seizes up, something locks the motor shaft from turning, or the motor simply fails to start properly. A failure to start may be caused by faulty start windings in a motor.

 

The thermal protector consists of one or more heat-sensing elements integral with the motror or motor-compressor and an external control device. The thermal protection is in place to turn the motor off when excessive heat is generated within the motor circuitry and keep it from burning up the motor.

 

These Thermal Protectors are reset when the motor cools to a safe operating temperature. There is usually a visible red button located on the wiring side of the motor, opposite of the motor shaft, but not always. In some cases, these buttons are reset manually, but not always.

 

Although having a motor shut down is inconvenient, it certainly is better than having to replace a motor. Just think of it as a second chance to find out what the problem is with the motor or the connected devices or load attached to it. 

 

You see, just because a motor fails to start or overheats during operation, doesn't mean that the motor is necessarily at fault. There could be an obstruction on the attached load to the motor, causing excessive load on the motor. This in turn causes excessive heat to build up in the motor and hopefully, the thermal protector trips the motor circuit to save the motor.

 

To help you select a suitable thermal protector, we need you to tell us the following:

Industry of the end customer to judge the rough model of Thermal Protectors, application of the thermal protector, electrical parameters (voltage, current), trip temperature, reset temperature, mounting position and space requirement to decide the size, normally closed or normally open, lead wire requirements, certification requirements.

DOs and DON'Ts on thermal protector testing:

Requirements to the testing device:
1. Temperature testing chamber shall be equipped with a PT100 temperature sensor at each corner to accurately and vividly and with show whether the temperature field inside the chamber is stable and even or not.

2. Temperature testing chamber shall be equipped with a stirring paddle at the bottom to propel air moving velocity up to 200m/min so that the air is well stirred and the internal temperature field remains stable and even.

1. Constant temperature point: The constant temperature point is 15℃ below the rated breaking temperature. When the chamber internal temperature reaches the constant temperature point, the chamber automatically keep the temperature constant for 5 minutes.

2. Temperature rising speed: The temperature rising speed is set to 2℃/min at the temperature speed constantly rising period.

3. Product position: The relative position of the thermal protector product in the chamber must be relatively close enough to the temperature sensor so as to truly and accurately reflect the real temperature of the product.

Thermal protector testing is professional and serious. Professional work needs professional equipment. Never try to use flames of a lighter or candle and the like to heat the thermal protector. Such actions are considered very absurd and silly by insiders in the industry. 

Differential of terms: thermal protector, thermal switch, temperature switch, temperature controller, thermostat 
The terms thermal protector, thermal switch, temperature switch, temperature controller and thermostat all refer to a mechanical device that contains a bimetallic strip sensitive to temperature and is therefore used to trigger a snap action when the temperature rises to a preset point. The snap action can cut off or put through power supply to control the protected device.
Thermal protector is the most standard term. As in most cases a thermal protector is used to protect the motor of a machine, such as vacuum cleaner, power tools, mower, washing machine, compressor, the thermal protector is often referred to as a motor thermal protector or a thermal motor protector. As the thermal protector can make or break the circuit like a usual switch, it is also called a thermal switch or temperature switch. A thermostat or temperature controller is used to control the temperature within a certain range. Unlike the motor thermal protector, the thermostat and temperature is often used in a heating device.