Adjustment of the speed of a DC motor

I'm working on something that requires a very low speed motor (~.5-4 RPM).
I found a motor that runs at 1.5v @ a maximum of 7rpm (5040RPM max with 1428:1 ratio)
I need however, something to lower and raise the speed of this motor. I know that people say PWMs for this, but the only one I can find is a 12 volt and has gotten mediocre reviews. Could I use this 12 volt PWM in this system, or could someone point me to a reasonable PWM that would work?

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iceng5 years ago
Are you up to building it ? A
sblaptopman (author)  iceng5 years ago
I have little to no experience with circuits and homemade electronics beyond wiring and the like. If I were to gear it down 2:1, and then use that 12 V PWM, would that work? Or would I have to find a PWM that was to work at a lower voltage?
The circuit can run off of 9 VDC but for the motor use 2 or 3 AA or DD cells.
lemonie5 years ago

You might do better with some gearing, motors can only be slowed down so far before they don't really work right.


Got to agree with L. a 10:1 reduction is pushing it for just voltage controlling it.
Gearing or belt is a MUCH better solution - and you get 10X more TORQUE out of the motor instead.
The motor is geared 1428:1... 7 RPM already  going down to 5 RPM is a
drop of 2856 RPM out of 10,192 RPM  is a 28% reduction in speed, well
within the eletronic realm.
The gear motor design often permits a gear man to exchange gear position
and change of ratio.
Unless it is a planetary gear... A
sblaptopman (author)  iceng5 years ago
The gear motor I found has four speed positions, and the 1428:1 is the highest there is
Sorry A. I read it as 0.5 to 0.4 RPM !!
Yes, you're quite right.