Experiment No.: 4
Making & Testing the Control and Power Circuit for Jogging Operation, Forward & Reverse Rotation of Sq. Cage Induction Motor Using Contactor Control.
To make & test the control and power circuit for Jogging operation, forward & reverse rotation of
Sq.cage induction motor using contactor control.
Making the Circuit:
- A start push button switch (NO) (START) is connected in series with stop push button switch (NC) (STOP) and an NC contact of a two way switch, FDJ. This is connected in series with a contactor, FD. This whole series combination is connected across any of three phase and neutral.
- A NO contact of contactor, FD is connected acoss the START switch.
- The NO contacts of FDJ is connected after STOP switch and before FD contactor.
- Another two way switch, RVJ and another contactor RV is connected as same as above.
- Three phase supply, RST is connected with Squirrel Cage Induction Motor through NO triple contact of contactor, FD.
- A set of NO triple contact of contactor RV is connected across the three phase supply and induction motor by interchanging any two phase connection as shown in diagram.
- There may be three kinds of running of the motor. (a) Normal forward starting and continuous running in forward rotation, (b) Jogging in forward rotation and (c) Jogging in reverse rotation.
- (a) To run the motor continuously, only START push button switch is to be pressed and released.
- To stop the motor only STOP push button is to be pressed.
- (b) To run the motor in Jogging forward condition, the two way switch, FDJ is to be pressed as per required time. Then the power is directly fed to the FD contactor, then NO triple contact of FD is closed and the three phase power is fed to the motor. Thus the motor runs in forward rotation till the FDJ is pressed. When FDJ is released then the motor is stopped.
- (c) To run the motor in Jogging reverse condition, the two way switch, RVJ is to be pressed as per required time. Then the power is directly fed to the RV contactor, then NO triple contact of RV is closed and the three phase power is fed to the motor by interchanging S&T phase among RST 3 phase supply. Thus the motor runs in reverse rotation till the RVJ is pressed. When RVJ is released then the motor is stopped.
The control and power circuit of this connection is made in EKTS softwere and tested successfully.