I take some off the shelf parts and connect them together to make a low cost treadmill DC motor controller.

Parts needed:
4000w or higher SCR motor controller (I used 10,000w from ebay)
Full wave Bridge rectifier ( I used KBPC5010)
200K linear Potentiometer

bigclivedotcom SCR Video:
   • Inside a "4kW" ebay power controller ...  






-mike manmade