Generally speaking basic control circuits are used in starting stopping sequencing and safety automatic interlocking of equipment and machines. The control circuit consists of relays relay contacts contactors timers counters etc.
Single phase and 3 phase ac squirrel cage induction motors need some type of control circuit to initiate a start or stop function.
Sequence starter motor control circuit.
The circuit shown in figure 31 13 makes this amendment. Motor 1 starts immediately when starter 1m energizes. The two types of ladder control circuits commonly used are the 2 wire control circuit and the 3 wire control circuit. The 1m auxiliary contact closes and energizes on delay timer tr3. So that each motor will start sequentially say motor 1 will start then after some delay then motor 2 will start and after some delay motor 3 will start. Sequence control circuit 1 one design that will meet the requirements is shown in figure 31 1.
3 easy to build speed controller circuits for dc motors are presented here one using mosfet irf540 second using ic 555 and the third concept with ic 556 featuring torque processing. So that whole operation will take 10 seconds to start all motors in a sequence. When the start button is pressed all cr contacts close. There are two rungs in the circuit of the plc program the first rung rung 0 in the circuit which is initiated by pushing the start push button switch pbw will run the first two motors motor 1 and motor 2 simultaneously for the first stage sequence leaving motor 3 on stand by. A circuit which enables a user to linearly control the speed of a connected motor by rotating an attached potentiometer is called a motor speed controller circuit. Scheme control circuit of star delta starter open transition the on push button starts the circuit by initially energizing star contactor coil km1 of star circuit and timer coil kt circuit.
There are total 3 motors to be controlled in a sequence. When star contactor coil km1 energized star main and auxiliary contactor change its position from no to nc. Control circuits can also be configured or programed in the plcs. If we wanted to keep the motor running even after the operator takes his or her hand off the control switch es we could change the circuit in a couple of different ways. The interlock contacts installed in the previous section s motor control circuit work fine but the motor will run only as long as each push button switch is held down. When motor starter 1 energizes the normally open auxiliary contact 1m closes providing power to coil 1m and to push button 2.
The 2 wire control circuit uses maintained contact devices to control the magnetic motor starter. In this circuit push button 1 must be pressed before power can be provided to push but ton 2. The addition of two timers make it possible to start the motors in sequence from 1 to 3 with a time delay between the starting of each motor as well as stopping the motors in sequence from 3 to 1 with a time delay between the stopping of each motor. We could replace the push button switches with.