Commonly Used Temperature Protection Components For Motors
Commonly used temperature measuring components for motor overheat protection can be roughly divided into two categories: one is fixed-value temperature protection components, such as temperature control switches and thermistors; the other is thermocouples and platinum thermal resistors, these protections The components are embedded in the corresponding positions inside the motor, which can directly reflect the actual temperature of the motor windings and bearings. Whether due to over-voltage, under-voltage, over-current, phase loss, overload, locked-rotor and other faults, all faults are caused by the temperature rise of the motor windings, and they are all caused by the temperature rise of the motor winding. It shows that the power of the motor is cut off immediately, which plays a role in protecting the motor. Today we understand the first category.
Temperature control switch: It is embedded in the coil of the end winding of the motor, bound and fixed, and its lead wire is drawn out with the motor lead wire and connected to the motor terminal. When the temperature rise of the coil of the motor running reaches the operating temperature of the temperature control switch, the temperature control switch can cut off the power supply of the controller, disconnecting the main circuit of the motor, thereby protecting the motor. Motors with different insulation grades can choose temperature control switches with different temperatures. For example, HCET-A automobile temperature control switch, the temperature can be selected in the range of 50-160℃.
Thermistor: PTC thermistor is usually used for motor protection. The PTC thermistor is small in size, small in heat capacity, and fast in response. It is not only suitable for undervoltage, overvoltage and overload protection of the motor, but also suitable for the lack of phase start protection of the motor, but it must be equipped with a special motor protector when in use. . When manufacturing the motor, the PTC thermistor is embedded in the motor coil, and the coil is dipped together after pressing and binding, and the lead wire is connected to the junction box. When the temperature of the motor coil is close to the insulation temperature, the PTC thermistor The resistance value increases; this signal is sent to the motor overheat protector, and the protector disconnects the motor circuit according to this signal, thereby protecting the motor. PTC thermistor is often used for motor protection.
