A design of intelligent electromotor protective device based on simplified thermal effect model

Owing to the different fault features of the asynchronous motor while starting and running, according to the protective principles of inverse-time over-current about asynchronous motor an electromotor protective method which uses simplified thermal effect model is given. With the technology of single-chip microcomputer, we have designed an electromotor protective device with all function .We are expected to explain the protective principles, introduce the functions and the structures of hardware. The main technology of "heat-accumulation" and "heat -emission" is discussed in detail. The device is characteristic of high integration, strong anti-interference, easy to use, etc. The device has been put into operation , and the practice shows that its performance is excellent.