MC-60 PWM Controller Modifications

[Chuck in E. TN]

I am cross posting this question to several forums.
I have 2 Proform MC-60 treadmill motor controllers, one of which is currently running my X2 mill with its (from the treadmill) 2hp motor.
I have it set up with the original heavy choke, and the original line switch/circuit breaker from the treadmill, and a 5k pot from radio shack for speed control. It works, but still has the soft start feature, and the pot must be turned up about 50% to start the motor. I found son instructions for modifying this controller to remove the soft start, and one that supposedly will allow setting speed and being able to turn the motor on and of at the last speed setting. Only problem, the controller schematic provided with these instructions, doesn’t seem to match the Proform MC-60 I have.
Has anyone modified this controller to remove the soft start? Will a 10k pot make the speed transition smoother?
I have a data sheet on the controller from Surplus Center which pictures the board and shows the connections, but not a proper schematic.

Chuck in E. TN

[velocette]

Hi chuck I am a big fan of DC Motors and Controls all my machine tools on DC Power using  "Dart, KB Electronics and Minarek" Controllers. You can get a control to stop and start on the same pot setting by inserting a switch on the "High" wire on the pot. This is just an indication of how it MAY be done.

All work on Electrical equipment you do at your OWN RISK AND RESPONSIBILITY   

Trying to be of some help Eric

[Chuck in E. TN]

I'll insert a switch in the high side of the speed pot and see if it helps. Thanks, Velocette.
 
Chuck in E. TN

[75Plus]

Chuck, a part of the problem may be the 5K pot. Pots are made in different tapers. The one you need is a linear taper meaning that as the pot is turned the resistance increases evenly. There are logarithmic pots that increase slowly at first then more rapidly as the knob is turned. Some of these pots can be reversed meaning that the high resistance is on the other end of rotation. The BEST kind of pot your application would be a wirewound type. They handle power well and are always linear.

Joe

[Chuck in E. TN]

Joe, the pot is linear.
 
Chuck in E. TN

[RKernell]

Stumbled onto these postings gathering data to use to drive a spindle drive for a Taig mill and another for a Taig lathe. Have the controllers proven to be good choses?

[Chuck in E. TN]

Mine is still running my X2 with no problems. I have a second identical set up on an arbor with wire wheels.
Chuck

[Brass_Machine]

Mine is still running my X2 with no problems. I have a second identical set up on an arbor with wire wheels.
Chuck

Hi Chuck,

Could you do a little bit of a write up? I am interested in doing this to my X2 as well, but am unsure as to which treadmill motor to buy, what to use as a controller etc...

Thanks
Eric

[Chuck in E. TN]

My experience with treadmill motors is purely the luck of the draw and what is available from Freecycle.Anytime a treadmill comes up on one of the local Freecycle groups, I try to get it.
I have collected about 6 of them. I have 5 that had DC motors and controllers. All the motors worked, but 2 had controllers that were damaged.
One had an AC motor and a variable pitch pulley that was mechanically controlled by a crank mechanism that changed the drive belt tension which allowed the spring loaded variable pitch pulley operate.
The best dc controller of the bunch I have is the venerable MC-60. It is small, contained with it's own heat sink, and has spayed connectors for easy re-wiring. The motors associated with thees controllers were just a bit bigger than the original X2 motor, and rated 2 1/2 hp.
I'm currently on the road visiting family and fishing my way across Upstate N. Y. so I can't take pictures of my set ups, but will try to remember to do so when I return to Tennessee the end of the month.
I'll search my laptop and Photobucket to see if I have any pictures with me, and post them later today.
Chuck

[andyf]

Chuck, it might be an idea to leave a short-duration soft start on it. Otherwise, if you press start with the speed control already wound up to a highish setting, the initial inrush of current might fry the controller.

I put a 2HP treadmill motor on my milling machine, using a KB controller, and have set the "Accel" pot so it takes the motor a second or so to get up to speed. As it takes me at least that long to work out which handle to turn and in which direction, no time is really lost.

Andy

[Chuck in E. TN]

Andy, the MC-60 type controller still has the soft start functioning. I could not find any mods to get it to remember the last speed. I have to turn the speed controll all the way to zero and back up to the speed I want, just like the origional X2 mill control. I replaced the counsole controls with a 5k ohm linear pot on both setups I use. The arbor setup also has a forward off reverse switch. I don't have a reason to run my mill in reverse.
Chuck

[mackn918]

  R42 Resister value For the MC-60 controller is..  *54.9K Ohm. the band colors are [Green-Yellow-White-Red-Brown]
If your motor does not start until the potentiometor is turned about half way replace or resolder r42 for fine motor control over full range.
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