Thread: 12 volt motor speed

You can only increase the amperage (I) by increasing the voltage (V) - since the motor internal resistance (R) is fixed.... Ohm's law is I=V/R

That's rigtht, increase the voltage and the motor will spin faster but then it will pull more amps. Gets hotter quicker and destruction is earlier.

Used to do that trick with slot cars to make them go faster. Went through a lot of motors.

Depending on what your motor will draw at full load, you could use this from Jaycar :

9 - 28VDC 10A PWM Motor Speed Controller - Jaycar Electronics

It is rated to 28V and 10 amps, and is a simple PWM generator, which will give you variable voltage therefore variable speed.

Otherwise you may have to look for a higher current rated PWM generator.

Torque will drop at lower speeds but DC motors are pretty good for that kind of thing. If you want constant torque that will require a lot of Googling.

Good luck.

Russell.

I assume you want variable speed, or do you want it to go faster than it does running on 12V ?

If that is the case then increase the supply voltage a bit, though it will blow up at some stage...

I would think that to get any noticeable speed increase in the motor by increasing the voltage, you would need to up the volts by quite a bit. More than 1 or 2 volts would seriously shorten the motor life, especially if it's a brushed motor with a commutator...
As an alternative, maybe keep it at 12 volts, and use drive belts to increase the spindle speed. Easy enough to do mechanically, but would keep the motor happily humming for a long time.
Just a thought

Not really sure what you want to eventually achieve, but with 12V and 15A, you have a max input power of around 180W, and a fairly inefficient motor. As a rough example a Dremel or clone is around 135W, and load down as soon as they are expected to do some moderate work, DIY grade 18V cordless drills are around 120W for compacts, 170W for medium duty (light duty hammer), but are working at low speeds so get extra torque from gearing down.

Unless you are looking toward a PCB drill or similar, 12V most likely won't cut it. Even a sewing machine motor is normally 200 -300W and are generally gutless on micro lathes or micro mills.

Sorry to be a pessimist.

Thanks for all the info, I will try a voltage regulator (PWM) with a higher voltage power supply (may be 24volt ) it may give me a bit more speed, it is only for trial on cutting printed circuit boards.