variable speed control for 12v motor?

[Vectra Dave]

Hi,
What I need is a system to allow me to control the speed of a small 12v motor by turning a knob. It has to go from zero to full rpm of the motor and have quite fine control over it. I have a 12v supply, so just need the speed control bit. The motor movement must be quite smooth, not jerky.
buy, build, rip out of an old appliance....?

any suggestions?

[alistairolsen]

you can buy manual servo operated speed controllers from model shops, maplins, or ripmax quite cheaply

[alistairolsen]

here: http://www.maplin.co.uk/module.aspx?...=30310&doy=1m7

[Dom]

Above link from Maplin is fine. Just watch how much current your motor takes.

PWM control of the motor is the only way to go really. Linear regulation wastes a lot of heat/power and reduces the torque of the motor significantly at lower speeds.

[Vectra Dave]

excelent, thanks.

[Xen0phobiak]

http://www.cpemma.co.uk/pwm.html

if you need more current, use a different mosfet.

[Chameleon]

You can pick up an old Model Railway controller no problem. They work from 0-12v and can be had pretty cheap. Mains powered too.

[fbm-spec]

How about an old battery drill motor control ..... high current rated :-)

[Andy^mk3]

You can pick up an old Model Railway controller no problem. They work from 0-12v and can be had pretty cheap. Mains powered too.

I think the model railway controller is best, and they're powered by 12v mostly, they have seperate transformers