I got another free treadmill yesterday because I saw it had an actual knob that you turn to control speed. I figured for sure it had an MC-60 controller. Well, after I got it home and apart, I saw it was much older than I'd realized. Its motor was about the same size as regular but was labeled 1.25 hp treadmill duty. And the controller is an MC-40.

The MC-60 I have in front of me has 5 output D4020L SCRs bolted to the heat sink/chassis with heat sink grease. The MC-40 has 5 output D4015L SCRs similarly mounted. Can I assume the MC-40 is rated for less current and thus smaller horsepower motors?

I found a schematic of sorts online. That's not really what I need. I need information on how useful an MC-40 is for repurposing treadmill motors to power small machine tools like a drill press.

Finally, I believe there has been significant puffery in horsepower ratings for treadmill motors over the last 30 years. Is it possible mine is basically the same as a newer one now claiming to be a 2.5 hp motor? I figure this motor is easily 25 years old and maybe older and so maybe its rating simply hasn't inflated as much as newer motors?

Thank you,
metalmagpie

 

I have never worked on a MC-40, but take a look at the SCR parts No rating on the respective spec sheets 's, this will give you an idea of the maximum current.
The T.M. units have a means of going into current limit anyway.

 

I have never worked on a MC-40, but take a look at the SCR parts. No rating on the respective spec sheets, this will give you an idea of the maximum current.

Just as you'd think, the D4015L are rated for 15 amps and the D4020L are rated for 20 amps. So I'm guessing the MC-40 is only good for 3/4 as much peak output current as the MC-60.

MaxHeadRoom, I'm sorry but I don't understand "The T.M. units have a means of going into current limit anyway."

 

There is a fold back or limit set built in as to what the SCR's will be subjected to, current wise.