There are three common DIY variable speed power supplies that people are using to power treadmill motors for their DIY projects: SCR voltage controller with bridge rectifier, Variac (variable transformer) with bridge rectifier, and an MC2100 with PWM signal generator. There are also other options but these are the most common and the ones used in the tests in this video. There are lots of opinions as to which one is “BEST”. I decided to hook each one up to my mill and test it for adjustability and loss of speed as a load is applied to the motor. This video goes in detail of the advantages and disadvantages of each type of power supply and by the end we will have some numbers to look at and make a logical decision as to which one is right for your application. If you are thinking of using an MC2100 you may want to watch one of my newer videos showing a problem https://youtu.be/yMkW2SXl_sA Affiliate links to items in this video: MC60: 10K potentiometer https://amzn.to/3QAtiES 20 Amp circuit breaker https://amzn.to/3ufQDRh OR 15 Amp circuit breaker https://amzn.to/3FgoQGP Emergency stop switch https://amzn.to/43mgveT 3PDT direction switch https://amzn.to/3ZShNLG OR DPDT center of switch https://amzn.to/46hjbdM MC2100: PWM signal generator for the MC 2100 https://amzn.to/3z3ivu3 20 Amp circuit breaker https://amzn.to/3ufQDRh OR 15 Amp circuit breaker https://amzn.to/3FgoQGP Emergency stop switch https://amzn.to/43mgveT 3PDT direction switch https://amzn.to/3ZShNLG OR DPDT center of switch https://amzn.to/46hjbdM Toroid Core for AC inductor/choke https://amzn.to/3QTk5Zs Variable Transformer: Variable transformer with 130 max volts https://amzn.to/40JAlhU 100 amp Bridge rectifier https://amzn.to/40DjWg6 Emergency stop switch https://amzn.to/43mgveT 3PDT direction switch https://amzn.to/3ZShNLG OR DPDT center of switch https://amzn.to/46hjbdM Toroid Core for AC inductor/choke https://amzn.to/3QTk5Zs SCR Voltage controller: SCR voltage controller https://amzn.to/47vUify 100 amp Bridge rectifier https://amzn.to/40DjWg6 20 Amp circuit breaker https://amzn.to/3ufQDRh OR 15 Amp circuit breaker https://amzn.to/3FgoQGP Emergency stop switch https://amzn.to/43mgveT 3PDT direction switch https://amzn.to/3ZShNLG OR DPDT center of switch https://amzn.to/46hjbdM Toroid Core for AC inductor/choke https://amzn.to/3QTk5Zs 10K potentiometer https://amzn.to/3QAtiES 20K potentiometer https://amzn.to/3Srib1a 100K potentiometer https://amzn.to/46anc3O 150K potentiometer https://amzn.to/3zxc96l Inclosuers and inclosure parts: 8” X 6” X 4” hinged box https://amzn.to/3jPndaR 8” X 10” X 4” Power supply box https://amzn.to/3HEHeun 12” x 12” x 4” Large component box https://amzn.to/3Imerv6 7.9” x 4.7” x 2.95” Large plastic box https://amzn.to/3nQEylT 6.22” x 3.54” x 2.36” Medium plastic box (the one I put all the parts in) https://amzn.to/40JB9nn Cable Gland https://amzn.to/3VZNrWb When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. The choke in most of my videos is part number 130993. Instead of getting one new I would get a used one. A lot of treadmills come with a choke. Go to eBay and search “treadmill motor choke” BUT know that most people on eBay don’t know what they have and the word "transformer" will also appear in most listings. Problem is a choke and a transformer look almost identical so some listings are for transformers and some are fore chokes because the sellers think they are interchangeable. They are not. They would only be interchangeable if you modify a transformer to work as a choke. (see my DIY choke video) To tell the difference count the wires. A choke will only have 2, a transformer will have 3 or more. Please let me know if I can be of further assistance.

• published: 24 Nov 2022
• views: 12769