Variable Speed Treadmill Motor Power Supply Shootout: SCR, Variac, & MC-2100 Which one is the BEST?
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://s.vevor.com/bfRuD6
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
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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.