Treadmill Motor Conversion On A Walker Turner Drill Press

That's a pretty rough looking PCB. Will you be able to salvage it?

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it's pretty grotty, but most boards from old treadmills are pretty scummy :) John's helping me troubleshoot it, so fingers crossed. I have a couple of diodes I can swap in, but I want to figure out what went wrong first. The annoying thing is that I can't remember if this board or the one that I put in my lathe control box was the one I pulled from a working treadmill. I got them both last summer and I've forgotten a lot since then!

Doesn't look like he smoked anything but the diodes. I've repaired worse.

fingers crossed! Not just for the cost of replacing it, but also the time fitting it to the case. These MC-40/60 drives are pretty compact.
 
it's pretty grotty, but most boards from old treadmills are pretty scummy :) John's helping me troubleshoot it, so fingers crossed. I have a couple of diodes I can swap in, but I want to figure out what went wrong first. The annoying thing is that I can't remember if this board or the one that I put in my lathe control box was the one I pulled from a working treadmill. I got them both last summer and I've forgotten a lot since then!

Right on man! I'm following this thread with much interest!

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thanks! It's all fixed, at least temporarily. Ordered some proper sized fuses and waiting to hear back about the suitability of the diodes I swapped in, but it ran up to full speed with no problems. No major vibrations, although at 4500rpm it looked (and sounded) like it wanted to take off :)
 
well, it's not fixed as it doesn't work again :( Just bought a new controller instead of trying to figure out what's wrong with it.

Finished the front plate and all the wiring that I can do for now. It'll be easier to finish all the box -> front panel connections once the controller board is in place.
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made a knock for the speed control and while I was at it, for an LED lamp I made for my wife a while back.
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alright, all finished! The new board arrives and I was too excited to wait until the new fuses arrived, so I pulled the old motor off the drill press and put the new set up on.

bottom half before joining. It's fairly crowded in there. Wire on the bottom right is for the tach head, black and red wires at the top left are AC wires for the tach power supply. Both those wires and the power wires for the sockets near the motor are tapped into the AC wires downstream of the main switch on the left.
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back of the front panel. The DC + and - wires come off the top two poles of the reversing switch in the middle - the 2 middle wires come from the board. Board power switch is on the bottom left, tach power supply (120VAC -> 9VDC) is top left, tach is top right and speed pot is bottom right
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I was just JUST able to plug the pot wires onto their posts (MC40 board is laid out opposite to the MC65 on my lathe). Then I realised that I still had to bolt the controller box to the drill press from the inside. That wasn't fun.
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everything mounted up. Had to partially remove the clock spring to get to the bottom right screw on the controller box - doh!
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close up of the motor and the socket box. There's enough movement in the original motor mount slots to access the top to pulleys of the intermediate pulley, which is really neat. Most likely it'll be left in the top one, just put it in the 2nd from top because it was easier for now.
Socket is wired and grounded to the main box switch, so turning off the box turns off the sockets, which I'm pretty chuffed about.
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here it is, in all it's glory! Wire on the right is the tach reader head, pointing up at the underside of the spindle pulley where I glued a rare earth magnet. Worked fine in testing.
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can't take it for a spin yet until the 10A fuses arrive. Trust me, I tried and immediately blew the 3A fuse (all I had in that size). Still, all the lights work and the tach works. Fuses should be here today, so I'll update the thread with speed ranges and first impressions. I'm super pleased that this is finally done!
 
finally got a few niggles sorted out and gave it a run through the speeds. I can put the motor belt on one of 2 intermediate pulleys, I only tested on the larger one as I didn't think to try the others yet (you can see it on the smaller intermediate pulley above).

That gets me 3 low speeds:
50-400rpm
300-1000rpm
500-1600rpm

sounds like it's about to take off at the high end of the speed range! I've also ordered a choke to put on the DC line as I found that smoothed things out and reduced noise on my lathe.

I'll check out the high speed range when I get home later.
 
had a bit of a diversion - new link belts, forward-reverse switch crapped the bed, took the low speed shaft apart (took me 3 years to figure out how!), made a carriage stop and finally checked out the high speed of this thing. get this, 4300rpm!!! low end of 1300rpm, so a nice range for wood or small bits. might have to add a heart sink to the case though, gets pretty warm at extended runs at full speed :)
 
That's not really a very wide range for a DC motor with closed-loop controll. You should be able to get 10:1.
 
that's for 30-100% of motor speed (going by the pot position). From experience with the one on the lathe, below 30% is fairly gutless. However, this is a more powerful motor (1.5 vs. 1hp) and the different type of cutting action may allow me to go lower on the dp than I can on the lathe. I'll see how it goes with use and report back.
 
that's for 30-100% of motor speed (going by the pot position). From experience with the one on the lathe, below 30% is fairly gutless. However, this is a more powerful motor (1.5 vs. 1hp) and the different type of cutting action may allow me to go lower on the dp than I can on the lathe. I'll see how it goes with use and report back.
I'm getting a 10:1 useful speed range on my lathe but that's with a closed-loop controller.
 
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