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PWM that will work with a reversible power supply

Bobwhite

Jan 28, 2021
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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.
 

Bobwhite

Jan 28, 2021
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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

Oct 5, 2014
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Pots are normally rated at around 1/4w, not suitable, and resistance inclusion also defeats the purpose of using pwm.
 

bertus

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Nov 8, 2019
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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.

Bidir_speed_control_schematic.png
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
 

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Bobwhite

Jan 28, 2021
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Can I add the PWM before the power supply? Will the PWM effect the operation of the reversible, remote controlled power supply?
 

bertus

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Hello,

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

Bertus
 

bertus

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Nov 8, 2019
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Hello,

No, you can not apply PWM on the powersupply.

Bertus
 
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