Motor cannot be started or slow down after starting

Motor cannot be started or slow down after starting

The reasons caused and the methods to solve out the problem of motor
There are five reasons why the motor can't be started or slows down immediately after starting, which are:
(1) line fault; 
(2) locking of protection electric control system;
 (3) improper installation and adjustment of speed (belt breaking) protection; 
(4) voltage drop;
(5) contactor fault. 

There are five solutions to the five causes of fault Methods: 
(1) check the line; 
(2) check the running deviation, limit position, parking along the line and other protection, and reset the accident after handling; 
(3) check the speed measuring device; 
(4) check the voltage;
(5) check the overload relay;