12v dc motor control-bi directional with PWM

[PaulJohnson]

Hello
I've just bought a small 12volt gear motor and it seems to work fine in either direction when I swap the wires over. I'd like to use one of the readily available speed controllers on EBAY but not sure whether these will work in both directions simply by changing the polarity?

 

[ScottyUK]

You can swap the wires manually, or using a DPCO relay, or you can buy a slightly more sophisticated / expensive controller which can do the 'swap' using the internal electronics rather than actually swapping the wires. It will possibly have the word 'bridge' in the description.

 

[LiteYear]

Just in case this is what you're thinking - swapping the polarity supplying the speed controller almost certainly won't work. As Scott says, the swapping must be done between the controller and the motor. That can be effected either manually, via a relay or within the controller itself if it supports it.

 

[ScottyUK]

Thanks liteyear, I missed that important point!

 

[PaulJohnson]

Thanks for replies
So I can switch the wires between the controller and the motor but not the wires from the power supply to the controller.
I did see in the description of one controller "reverse polarity protection" which got my alarm bells ringing. I also saw a controller that would switch direction and control speed from the same pot for about £25 which may be a better idea but not sure it has the power capability for my motor