The role and development direction of thermistor in the motor

The role of thermistor in the motor:

The thermistor is a class of sensitive components, which are classified into Positive Temperature Coefficient (PTC) and Negative Temperature Coefficient (NTC) according to the temperature coefficient.

Thermistor is generally used in household appliances for overheat protection, mainly to measure whether the temperature of electrical components is overheated, and automatically disconnects the road to form protection when overheating. For example, the rice cooker thermostor is to control the temperature of the rice cooker. On the one hand, it will not overheat. On the other hand, when the rice is cooked, it can jump to the heat preservation state.

The working mode of thermistor in the motor is as follows:

Thermistor is mounted in the motor and is usually mounted close to the motor windings to monitor the temperature rise of the motor windings. Generally, the negative temperature coefficient of the thermistor is used. When the motor is overloaded, the resistance of the thermistor will decrease when the winding temperature rises. When the resistance value drops to a certain value due to the temperature rise (this value is set according to the characteristics of the motor or the use requirements) The fixed circuit will cause the control circuit to take action to cut off the motor circuit, so that the motor stops working and protects the motor.

The direction of thermistor:

The thermistor is a resistor whose resistance value is extremely sensitive to temperature. It is made of single crystal, polycrystalline, and semiconductor materials such as glass and plastic. Basic characteristics: The resistance value changes extremely with temperature, and the volt-ampere curve is nonlinear.

NTC mainly suppresses the inrush current of the power input switch. Because the power switch is instantaneous, the input surge current is very large. In order to reduce the inrush current, the series negative temperature thermistor, when the input current is stable, the resistance value drops sharply due to the rise of the thermistor temperature, which is equivalent to no resistance, lowering The power consumption.

With the development of technology, electronic components require small size, high power, low power consumption, and high reliability. Thermistor's development direction is smaller under the same resistance and steady-state current. At the same resistance and volume, the steady-state current is larger and has a stronger resistance to current surges.