Pot for motor

[Vass]

I've managed to source an electric wheelchair motor which has integrated into it both axles and I guess a slip diff i.e If I hold one axle, the other spins at twice the rate.

There are 2 sets of wires coming from the motor, 2 brushes I guess. If I wire in series, the motor turns at half the speed. Still too quick for my needs though

so, 12v sealed battery 24Ah, is being used to power this motor (no idea about motors spec) What Potentiometer could I get to regulate the speed? (A maplin link or similar would be great) TIA

[Bob Minchin]

A potentiometer (pot) is not suitable to control such a high power motor. The dissipation (wasted power) would be far too high and let out the smoke. You need a proper controller designed for such motors which in turn will use a low power pot to control it. Suggest you look for a controller from an old chair or small golf buggy or maybe lurk around in railway modeller forums who use such things for larger ride on electric locos. Another possibility is controllers for childrens electric bikes, go-carts etc.

Bob

[Vass]

ah ha, wondered as much, thanks Bob

[The Natural Philosopher]

Don't even think about it. It will be massive.

How many amps does it draw? your best bet is to couple up a model controller and a 'servo tester'..and put the windings in whatever mode will give you 'desired top speed' These things are variable switched regulators, in essence.

Model controllers up to about 100A are available though not that cheap, and a 'servo tester' is peanuts. 12v is a perfect voltage.

If you want to delve further into this approach, have a look at this site

register to ask questions.

Not a few people with electric wheeled vehicle issues have been sent away educated and happy ;-)

[geoff]

In message , Vass writes

Try a kilowatt electric fire and a jubilee clip

yer standard pertentiomammers would lose their magic smoke faster than the speed of light If you tried to use it for such an application, they are normally rated at 1/4W. You can get higher, but what you need is an electronic control. Without knowing the power of the motor, better advice is difficult

[Vass]

what about this?

|65%3A1|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A100I'm guessing it would attached to a 12V machine so may do the trick?

[The Natural Philosopher]

|65%3A1|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A100

My guess is its a couple of amps only.

Get something sized for the job!

[The Natural Philosopher]

A browse here may help

[The Wanderer]

Take a look here. Others have told you an 'ordinary' pot won't do the job. This guy has built his own powerchair. He is a quadraplegic, just so you know, but seems very knowledgeable about the electrics for wheel chairs.

[Steve Firth]

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember [e-mail] (Steve Firth) saying something like:

Or a Scorpio V6

[meow2222]

As said, an electronic controller is the ideal thing if money is no object. There are also much simpler options if your wish list is shrunk. 3 that spring to mind are:

1. series diode or 3 to lose a little voltage
2. if the battery has its interconnects accessible, and most dont, you can just connect to whichever tapping gives the speed you want
3. A vibrator can chop the supply to the motor, thus slowing it down. This has its issues, but is sometimes sufficient.
4. finally you could make your own switched mode variable regulator if you can do electronics. Not a beginner's project, but not too bad complexity-wise.

NT

[Graham.]

His carers both look like goers too ::::-)