PWM that will work with a reversible power supply

[Bobwhite]

I am running a small 12 volt motor with a 12 volt, reversible, remote controlled power supply. I need to be able to adjust the speed of the motor. I have seen PWMs with a reversible switch, but that would not work for my application. Is there an off the shelf PWM that will work with reversible current ? All the ones I've seen say reversing the polarity will damage the PWM.

 

[Bluejets]

No.
Pwm control will need to be before reversing switch.

 

[Bobwhite]

Thanks

 

[Bobwhite]

Couldn't you put a potentiometer in the circuit to slow the motor speed? What would happen when the poles were reversed to the POT?

 

[Bluejets]

Pots are normally rated at around 1/4w, not suitable, and resistance inclusion also defeats the purpose of using pwm.

 

[bertus]

Hello,

Could you use a DC control voltage?
Then have a look at the attached article.
The control voltage can be in place of the potmeter.


At ca. 52 % Vcc the speed is max forward.
At ca. 33 % Vcc the speed is 0.
At ca. 5 % of Vcc the speed is max reverse.

Bertus

 

[Bobwhite]

Can I add the PWM before the power supply? Will the PWM effect the operation of the reversible, remote controlled power supply?

 

[bertus]

Hello,

In the given circuit IC1b, IC1c and IC1d will perform the PWM action.
It is controlled by the voltage coming from IC1a.

Bertus

 

[Bobwhite]

Can I add the PWM before the power supply? Will the PWM effect the operation of the reversible, remote controlled power supply?

 

[bertus]

Hello,

No, you can not apply PWM on the powersupply.

Bertus