[mark c]

Hello all,
I'm using a treadmill motor and controller obtained from Surplus center for my mini-mill. I want Mach 2 to be able to control spindle on & off, but when the spindle shuts off then on, you have to turn down the pot all the way then back up to get the spindle on again. It uses a 5K ohm pot. I found that if I disconnect one of the pot leads from the control, then reattach it, the spindle goes back on at the previous speed. I figure that this is like having a pot with an on/off switch built in.
My question (or two) then is: if I put a relay in series with a lead from the board to the pot will I damage anything? Will it make any difference which lead I use?

Thanks in advance

[Al_The_Man]

No you should damage anything, your simulating turning the pot down, what type of controller is it? as some have a mod that can be made so you do not have to turn it down first.
Al

[mark c]

Thanks for the quick reply

This is the control:
http://www.surpluscenter.com/item.as...tname=electric

I figure if I wire in a relay controlled by Mach2, this will turn it off and on as with the original motor and control.
Is there any way to control thr rpm with this board?

Thanks again

[Al_The_Man]

This look very similar to the one sold with the universal motor. Does it have a TDA1085c for the main control IC? if so I have the schematic and mod for the Pot.
Al

[mark c]

Don't think it has that one. looks like #TLP3052? it's a small white chip about .25 x .375. there are two larger chips too
I'm gonna go ahead & hook up the relay and see what happens

[mark c]

Works like a champ!!!
Thanks Al

[Al_The_Man]

#TLP3052? . there are two larger chips too

The TLP3052 is an opto, are the larger IC marked?
I would be interested in what they use.
Al

[Fred in NC]

To disable the ramping? Thanks

[miljnor]

hey Al thats the controler I started with the two larger chips are. LM324N's

and 5 transitor/diodes's

[Al_The_Man]

This was the one that used the TDA1085 it looks identical to the one in the link from Surplus, but the ramp circuit may be close.
For the speed control you just remove transistor T3 from the board. The other mod entails cutting the trace to pin 6 of the chip and then solder a jumper from pin 6 to ground (pin 8). This mod was the most important since it allowed the motor to have the power required out of it. What it does is removes the slow soft start feature (it's still fairly soft just not extremely). This allows the controller to respond to sudden heavy loads such as the cutter engaging the work on a lathe in power feed without lagging so much as to let the motor bog down.
Like I said this is an earlier version of the controller.
Al

[miljnor]

there is nothing that is listed t3 . are you talking about the minark controler?

This is one made by Icon health and fitness MC-60 rev 407 9949