Hi all, not strictly car related but is kind off. . . .

Anyway. I have a 200W motor that I need to vary the speed on. 200W @ 12V means that its pulling around 17A which is well beyond the basic potentiometers or potential divider circuits.

I dont want to go into complex timing or PWM circuits, I just want to dial in a speed!

Is it an OP Amp and controller circuit or am I over cooking this? Im the only person in my company that understands electronics but 200W is beyond my comfort zone!

Cheers,

Biz

Get one of the cheap chinese electric bicycle controllers off ebay and save the hastle

Reversible 200W DC Motor Speed Control PWM Controller

The MK1 mini had a big potentiometer for the heater fan. item no 390381086518 brand new from Lucas.

Adjustable Heater Switch (Rheostat) for Austin Morris Mini Mk1 1/4t Van 1959-67

I'll go and have a look in the garage, I may have what you want. It's a small control board that I made ages ago to control the speed of a fairly beefy d.c. motor, used to spin a quite heavy lighting unit.

Potential divider networks up to 3Kw are quite cheap. They are called fan heaters.

[Edited on 12/12/12 by Confused but excited.]

Found it!
It has a TIP 34C output stage and if memory serves, it will only handle a max O/P of 15A the circuit is quite simple and if you are OK with simple electronics, it shouldn't be too hard to beef up the O/P stage.
If you want to U2U me your mobile no I will send you a photo.
If it's any good to you, you are welcome to it. I made it in 1986.

Fill your Boots :-)
http://www.hobbyking.com/hobbyking/store/__9090__Turnigy_20A_BRUSHED_ESC.html

Thanks for all of your help guts. Still LCB comes up trumps.

Confused - Replied to your U2U.

Thanks

I was also going to suggest a brushed r/c ESC with a $2 servo tester attached to it