I am adapting a MC-30 speed controller and a 90v 8 amp dc treadmill motor for a drill press. I tried getting the speed controller to work with the motor and wire the potentiometer. Unfortunately i can not get the motor to run correctly. I used a 50k pot which had 6 pins in which i used 3 this being because i had one at hand. The motor will turn on but will turn off then back on. Is this because of the high resistant poteniometer or just because i wired the pot incorrectly?

 

We need photos and wiring diagrams to see what you did.

Otherwise people can only make wild guesses!

 

Here is the photo I do not have the green wire connected and the motor it self is not grounded. Oh and the pot was from an amplifier to fine tune.

 

What adjustments are there?

Is one marked IR ?

 

Yes there is,there's 3 adjustments
One said's Max. its a 5K91 marked on the adjustment
Other one I.R. also a 5K91
Other one CUR. 2M92

 

If the IR is mis-adjusted motor will pulse under light loads.

It's not a critical adjustment for your purpose.

Set max (speed) at minimim to start.

Set CR (current) at max to start. Remember original setting for current.

 

Tried to get it as detailed as possible from an iphone camera. Oh and I did not adjust any knobs that red goop they use from factory to set the settings fell off.

 

Some of the MC series had the reed switch go to the board and then the display, does yours have this feature?
I only have the info up to the MC-60.
The typical pot value is 5k-10k linear.
This is the lower end SCR version, the later type were PWM.
Max.

 

Try the IR at either extreme.

 

This board looks almost like the mc-60 the connectors are all the same.
"Some of the MC series had the reed switch go to the board and then the display, does yours have this feature?
I only have the info up to the MC-60.
The typical pot value is 5k-10k linear.
This is the lower end SCR version, the later type were PWM.
Max."
No reed switch that i can see
Should i get a 5k-10k linear pot first?
Can the 50K cause any harm?
Also one last thing before i start playing with this again can you verify i have this pot even hooked up right? If you know the right connections for the mc60 i can piggyback the same thing here

I have 1 connector called speedpot
1 saids white
1 saids black

Do they use the same as AC current black hot
white neutral
green ground

If so I don't think i have this wired correctly.

 

The 50k should not do any harm, but it is not usually the optimal value of 5k.
On yours AC1 and AC2 are supply in and A+ and A- are the motor.
On the MC-60 the pot is L=com, W=wiper, H=12vdc.
Check to see if you have 12v across the outer ends of the pot.
Max.

 

The max pot has 1.7volts.

Also which terminal on my pot is the wiper? The middle?
I have a L and W terminal and the other is a speedpot no letter

 

The motor + and - terminals read 56 volts

 

The center is the wiper, the lettering may be different than the MC-60/80.
But normally you should expect 10/12vdc across the outer and from one end to the slider should go from 0 to 10/12v as you rotate.
The outer is supplied from the 12vdc source and the slider should go into the pin of a analogue/op amp IC.
Max.

 

Also most of the T.M. motor drives that use a pot, require that you go to zero on the pot first, so that the motor does not start when you plug it in if the pot is off zero.
Max.

 

Oh geez sorry man your name is Max and i though when you ment check the pot u mean the max on the board. I rechecked the pot i installed and now its working I have terminal 1 on terminal L(black) then W(white) goes to center pole the wiper and speedpot terminal 3 the ground. The only issue is when i have my voltmeter on the + and - terminals the pot only goes from 50 volts to 100 and slowly turning the knob it takes 5 seconds or so until it moves up a little. Also when hooked to the motor and i turn the knob the motor turns off and on 3 or 4 times then spins fine. Possibly just a pot issue?

 

must be because pot will not go to zero

 

The only issue is when i have my voltmeter on the + and - terminals the pot only goes from 50 volts to 100 and slowly turning the knob it takes 5 seconds or so until it moves up a little. imes then

??You normally would read 12vdc across the pot?

Max.

 

I mean the terminals that go to the dc motor(A+,A-) not the pot terminals, the pot terminals have 12v across the pot

 

Then It could be the 50k pot if it goes into a start prevention circuit?
Max.