DC motor control for 180v dc motor, will this work ?

[carl0s]

Hi guys. My new Weiss wmd20 mill came the other day, and I blew the speed control board almost right away. The s6025L SCRs exploded. I replaced them, but there's no DC output to the motor. Maybe the d6025L rectifiers are broken, but I don't know enough about electronics and I can't buy those in England.

While I await a replacement speed controller board, I was pondering how I might get the machine going, or even how I might do it if this ever happens again.

I think (will check) that the motor wants 180v. Supply power here is 240v. So, would the following do the job for running my mill's motor? :

Dimmer switch / triac, into a transformer with a ~125v secondary winding, into a bridge rectifier. In theory I'd get 180v DC with the dimmer switch all the way up, right ?

Is that a good or bad idea ? I know very little about electronics. Would there be an issue in that low-speed would be missing torque that would come from a proper speed control circuit ? Or might I find that the motor overspeeds anyway ?

cheers,
Carl

[Al_The_Man]

The SCR drives made by KB or Baldor are 120v or 240vac for 90v or 180vdc motor, I am not sure if they are available in the UK but someone may make an equivalent, they are fairly cheap on ebay.
Al.

[carl0s]

Originally Posted by Al_The_Man The SCR drives made by KB or Baldor are 120v or 240vac for 90v or 180vdc motor, I am not sure if they are available in the UK but someone may make an equivalent, they are fairly cheap on ebay. Al.

Thanks. I don't see anything like that on eBay UK though. I suppose I could buy one from the US for next time..