Motor Control Circuits. Generally speaking, basic control circuits are used in starting, stopping, sequencing, and safety automatic interlocking of. Motor control circuits are an effective way to reduce cost by using smaller wire and reduced-amperage devices to control a motor. Imagine trying to wire a. 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.


Author: Ms. Jewel Pollich
Country: Malawi
Language: English
Genre: Education
Published: 24 March 2016
Pages: 227
PDF File Size: 13.6 Mb
ePub File Size: 20.83 Mb
ISBN: 386-2-42199-141-9
Downloads: 83094
Price: Free
Uploader: Ms. Jewel Pollich


This being the case, the normally-closed, timed-closed contact of TD1 between wires 8 and 5 will have immediately opened the moment TD1 was energized.

Motor controller

When TD1 times out, the contact will close and the circuit will allow M2 to be energized if the reverse pushbutton is pressed. The careful observer will notice that the time-interlocking functions of TD1 and TD2 render the M1 and M2 interlocking contacts control circuit for motor.

Each time delay relay will serve a dual purpose: The starting torque however also reduces by a factor 3. Then after a while, connect the windings in delta configuration with contactor K1 and K3.


Star—delta starter working The main contactor K1 will energize only when the control circuit fuse F3backup fuse F1and the overload relay F2 are healthy and the start pushbutton S1 is pressed. Reduced-voltage configuration star configuration Star—delta timer coil K4 gets control circuit for motor through fuses F3, F1, NC contact of stop pushbutton S0and NO contact of start push button.

As start PB S1 is pressed, the timer coil K4 will pickup and in turn energize the star contactor coil K2. Now, the main line contactor K1 and the star contactor K2 are control circuit for motor a pickup condition, which will drive the motor in the star configuration.

Motor controller - Wikipedia

Full voltage delta configuration As the time duration set on a K4 timer star to delta timer elapses, the contactor coil K3 is picked up and at the same time, control circuit for motor star contactor K2 is de-energized.

Now, the main line contactor K1 and the delta contactor K3 are in a pickup condition, which will drive the motor in a delta configuration.

When the motor trips in an overload condition either in a star or delta configuration, the control circuit always ensures that the motor restarts in a star configuration, control circuit for motor than the delta configuration.

Autotransformer 3-phase starter Figure 3 shows the autotransformer three-phase starter circuit. This type of starter circuit uses an autotransformer to apply reduced voltage across the windings of the motor during startup.

AC Motor Control Circuits | AC Electric Circuits Worksheets

Three autotransformers are connected in the star configuration and taps are selected, to provide an adequate starting current for the motor. After a certain time lapse, full voltage is applied to control circuit for motor motor bypassing the autotransformers. Question 8 The starter and overload heater assembly for an industrial control circuit for motor motor is often located quite a distance from the motor itself, inside a room referred to as a motor control center, or MCC: Since it is impossible for a technician to be in two places at once, it is often necessary to perform diagnostic checks on a malfunctioning electric motor from the MCC where the technician has access to all the control circuitry.


One such diagnostic check is line current, to detect the presence of an open motor winding. If a three-phase motor winding fails open, the motor will not run as it should. This is called single-phasing.


control circuit for motor A good way to check for this condition is to use a clamp-on inductive ammeter to check line current on all three lines while the starter is energized. This may be done at any location where there is physical access to the motor power conductors.

Suppose, though, you are working on a job site where single-phasing is suspected and you do not have a clamp-on ammeter with you.

You are about to head back to the control circuit for motor to get a clamp-on ammeter when a more experienced technician suggests an alternate test. He takes your DMM, sets it to the AC millivolt range, then connects the test probes to either side of each overload heater element, one heater at a time like this: