The electric motor thermal protector in Our country has experienced several stages, such as comprehensive imitation of suo, self-design, updating and intelligent development. It is worth mentioning that because of the development of microprocessor technology in recent years, it provides a hardware platform for the intelligent and multi-functional development of motor protector, which makes the motor protection enter a stage of rapid development.

This kind of motor thermal protector mainly by single chip microcomputer as the controller, which can realize intelligent comprehensive protection of the motor, sometimes with remote communication function, can be realized in PC of as many as 256 computers connected to the motor to realize online integrated monitoring and control, the precision of sampling and setting have a qualitative leap, but the sampling signal nonlinear correction software, And can realize true RMS calculation, thus greatly reducing the impact of measured signal waveform distortion, really realize high-precision sampling, in the setting aspect of digital setting, through the keyboard by the user's own field setting, there is no error, but also for overload protection can set a number of more scientific inverse time curve.

Because of the use of the single chip microcomputer makes it possible to set a variety of functions and integrated protective device in the same hardware conditions. With the development of microelectronics technology, motor thermal protectorsare developing towards the direction of intelligence, integration, high precision and high reliability.