Wednesday, January 1, 2020

Three phase induction motor reversible starter

Introduction :- Many application requires the direction reversing of induction motors.for example electric hoists, electrical overhead cranes, lifts used in industries. Electrical actuators for operating gates in pipe lines for flow control. now a days various door control mechanisms are also using reversible motors.

Basic:- direction of three phase motor is changed by inter changing the supply phase sequence by inter changing two phase connection.

Circuit diagram :- circuit diagram is given below.


 It uses two Contactor, main circuit bagrker , over load relay, and three push buttons for forward reverse and stop. Three indication lamps can be used to indicate status of running of motor. MCB is first switched on. Forward button is pressed to run in forward direction. When forward push button is pressed C1 contactor picks up and motor run in forward direction and L1 indication  lamp indicate forward running of motor. To stop motor stop button is to be pressed, it dropped out contactor and motor stops L3 indication lamp indicate the motor is stopped. Similarly to run in reverse direction reverse button is to be pressed, it picks up C2 contactor which run the motor in reverse direction by inter changing power supply two phases. This type of circuit is used in all reversing operation with minor changes. Some reversible dol starter use external ICTP in place of MCB. Some places indication lamps are not used. In this 230 volt control is used in some circuit 400 volt or 110 volt control supply is used. In case of overload of motor, thermal overload relay trips the motor and save from burning.

Three-phase-synchronous-motor
no-load vector diagram of-transformer

2 comments: