Hey I am building a bubble machine for a project and I can only use 6V max for power. I need to be able to control the speed of one of my motors. Should I use a potentiometer? I have one but I can't get it to work. The motors are 1.5V-3V and being powered 2 AA batteries each. I tried wiring a potentiometer in between the batteries and motor but I cant get it to work properly. The potentiometer is a 100k Ohm Linear Taper Potentiometer, 250VDC .25W. I don't really know what I'm doing with so help would be very appreciated.

 

You need a much lower value pot. Try a 10Ω or a 100Ω pot. Wire only to wiper and one end.

__________________
Mike ML.

 

OK where can I get that? I got my last one at Radio Shack but I dont think they had any low Ohm pots.

 

And of course a more efficient way would be PWM.

Problem with a potentiometer is power wasted and heat. If you decide to use a potentiometer, please consider a power resistor in series with the pot and motor of a low enough value as to not deter from the circuit but to current limit the motor. It's a small motor but .25 watts isn't much for your pot and it might get very hot otherwise.

Look into PMW, it is way more efficient and friendlier to your components.

 

Mouser, digikey, newark, jameco.

Internet mail order.

 

What is a PWM? I'm new to this stuff so I meet need an explanation for this stuff. Sorry

 

Goggle for "DC motor speed control" and you will find several tutorials on the subject, including the PWM way.

__________________
Creationists have a world of evidence

 

But isn't it an AC motor because I am running it off batteries?

 

Batteries produce DC.
You were told to Google a DC motor speed controller that will explain Pulse-Width-Modulation (PWM).

__________________
Uncle $crooge

 

YIKES

No, no, no, no and noooooooo.
I am so glad, at least, that you are working with low voltages. Please go read up on basic DC/AC electronics!

 

Haha yea, like I said I'm new this stuff and I need help. I need something cheap to control the speed of a 1.5V-3V motor. Would this work?
25-Ohm 3-Watt Rheostat - RadioShack.com

 

Should do.
Put it in series.
Use only the middle and one end, as has been said.

Lets us know how it goes.

John

__________________
************************************************** ***************

 

Yea everything works. I bought a 25 ohm rheostat from radioshack and I am able to control the speed of my motor. Thanks a lot guys!!

 

Good deal.

I hope you will continue to study in order to understand why it worked... don't be content with this one success, but go to the next level and be able to forsee a result before the attempt.

Added: Also thanks for coming back to let us know your progress. Often, we never know the end result of someone's problem.

__________________
Creationists have a world of evidence

 

Frequently when somebody connects a potentiometer in series with a DC motor to control its speed simply reduces its torque so it cannot start running.

__________________
Uncle $crooge