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Using a DC motor speed controller as an "off" switch?

Madsalts

Sep 25, 2014
73
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Sep 25, 2014
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73
I purchased this DC motor speed controller:

http://www.amazon.com/gp/product/B00F839VNQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Now, I have another aspect of the project. Here, ideally, I'd have a motor that would be either off or on (with varying speeds). When experimenting with this speed controller, I have found that if the knob is turned far enough, the speed of the motor slows to the point that it actually stops.

It has occurred to me that I could use this one device to control a motor being either on or off. Then, if on, the speed can be controlled. The only reservation that I have is wondering whether turning the potentiometer on this device so low as to disable a motor is in any way unwise or harms the motor. Any thoughts? Thanks.
 

ADRT

Nov 25, 2014
192
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Nov 25, 2014
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192
Dropping the voltage so low as to bring the current up to the point of stalled or locked rotor situation may be catastrophic. More information about the circuit would help.
 

hevans1944

Hop - AC8NS
Jun 21, 2012
4,739
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Jun 21, 2012
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4,739
The device at the website you linked is a PWM controller, specified to control from 0% to 100% duty cycle at 15 kHz. The peak-to-peak output voltage of this PWM controller is constant at approximately 5 V. Only the width of the DC pulses applied to the motor changes. Your motor should not be harmed by adjusting the control to minimum pulse width (zero speed). Note this PWM controller can also be controlled with a 0 to +5 VDC control signal from an external source, a nice feature.
 
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