In order to insure electric-motor running safely,and to be immune to burn-up while lost its phase,besides of general safe considerations,some other protections should be taken into account such as lack-phase protection,so the rest of this paper will depict why an electric-motor lost its phase and how to deal with the problem.

An over current protection strategy which is capable of resisting striking for inverter is presented, the phenomenon of invalid protection is also analyzed, and the solution is provided at last.

This paper puts forward an over current protection circuit for CMOS class-D audio power amplifier applications.

One of key technology in IGBT is of over current protection which not only affects the performance and operation safety of IGBT component itself,but also the performance and safety of the whole system.

A New Composite Strategy of IGBT Overcurrent Protection for High Power Voltage Source Inverter;

Analysis on switching over station power which cause station transformer overcurrent protection maloperation;

Design of an overcurrent protection circuit in low dropout linear voltage regulator;

A simple IGBT drive and over-current protection circuit;

Meanwhile,three important protections(over-current protection,leak-power protection,earthing protection) as well as the other protections under the well are described in detail,which embody that these protections are significant to secure production and products of coal mine.

Based on allocation anaylysis of the fuse protection and relay protection of distribution transformers, the basic selection principle of over-current protection is determined.

According to the problems of its design and application,this paper puts forward the improving methods and designs the circuit of the voltage regulator with short circuit protection and overload protection.