Controlling DC motor with relays

Thread Starter

adrixas

Joined May 19, 2016
1
Hello guys,

Is it possible to control a dc motor both ways using two relays? With only one control wire, that changes from earth and12V?
 

Alec_t

Joined Sep 17, 2013
14,313
Surely the motor needs at least three states: Off, Forward, Reverse? Don't see how you'd do that with only one control wire unless you could cycle through the three states.
 

crutschow

Joined Mar 14, 2008
34,428
The direction control can indeed be done with two 12V coil, SPDT relays and one control wire.
Connect each relay wiper contact to the motor.
Connect one relay NO contact to the supply voltage and the NC contact to ground.
Connect the other relay NC contact to the supply voltage and the NO contact to ground.
Then with the motor will go one-way when both the relays are energized and the other way when they are both de-energized.

But if you want to be able to also stop the motor with those relays, then you need to control the relays with separate wires.
 

MrSoftware

Joined Oct 29, 2013
2,197
If you don't need off-state, then you can do it with a single DPDT relay as shown below. Connect your source + and - to the "COM" pins. Connect the left NC to motor + and right NC to motor -. Connect the left NO to motor - and the right NO to motor +. Connect one side of the coil to ground and the other is your signal. The motor will always be on, but when you give power to the coil the motor will reverse.



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