I caved and bought a proper enclosure - a BUD CN-5707 from Amazon for $13. Given how much time it takes me to do anything, I figure that's a night or two of shoptime I can spend on something else for not much money.
got the pot, thanks Jake! also got the case and the dpst switches so I'm just waiting on the reversing switch to start wiring things up. the fan does blow allot of air with the motor run ccw so cooling at looks speeds should be okay - high speeds will be interesting though
I am SUPER PUMPED! Totally completely pumped. I can smell the end and it's not burnt wire insulation either! Pictures will come later when I get home, but in the meantime:
1. gave the motor a coat of black paint to spiff it up. Looks rather nice now.
2. fitted the drive into the alu case I bought, heatsinking the whatsits to the case so there's a ton of surface area for cooling
3. wired in one of the DPST switches and it works and glows
4. trued up both pulleys, which will hopefully reduce vibration as much as possible
5. tested the tach and it works a treat, although 3000rpm is a little scary!
6. and best of all, cutting resistor R19/ RPS3 (connected to the wiper post of the pot) does away with the need to zero the pot to start the motor. It now starts at the same speed. How cool is that? Even found the same resistor (I think) on the MC40 board from my old treadmill. Woohoo!
Starting to do the lay out on what goes where in the control box. Haven't figured out how to attach it to the bench yet though..
thanks! I'll stick some thermal goop/ toothpaste/ armpit fluff at all the junctions when I finally put it together. The original plan was to put the whole sled in there but I didn't realise that the box tapered down to the bottom. Worked out perfectly in the end though
Struggling a bit with the 3D layout. I think I'll make a cardboard box model and stuff things into that first, before I go cutting into the housing.
thanks Jake! I'm trying to push this through as all hell is about to break loose when the semester starts next Tuesday and I know I won't have much time for anything not work related until Thanksgiving. Unfortunately the list of projects keeps growing!
too right! I just got given a bunch of alu and steel (CI?) disks from the Geo department that they charged with diamond dust for grinding and polishing rocks, so that's another project Just the use for the motor off my drill press when I put a treadmill motor on it..
IT RUNS! There's a bit of vibration and humming coming through the bench, so I need to work on the isolation a bit more so no vid, but here are some pics.
Slowest speed without backgear - using back gear gets me down into the 10-20 range, although the tach doesn't pick up very well below 30rpm.
max speed in that gear, so there's considerable head room if I use one of the larger pulleys if I ever need it (or have the cojones)
motor set up - the motor pivots on that wooden block so I can fine tune the pulley height. Didn't actually mean for it to work that way, I just drilled the holes in the bench from the wrong side of the block
Tach pickup. I should make something a bit more robust but this works just fine for now
woohoo! Thanks to everyone for their help, it's been a fun project and I am totally pumped by being able to vary speed on the fly. Have to work up a simple chart of speed/diameter/material/cutter to laminate and stick to the splash guard.
One thing I have learned though is the merits of right angle spade connectors - it was a real effort to get the front on that box, especially with all the PITA 14 gauge wire in there.
well I'm really glad I bolted rather than crimped the motor connectors - I had a nagging suspicion that I'd wired the F/R switch wrong - as I was showing off the F/R to the wife and saw that it was running forward in reverse!
But I did mostly get rid of the hum and the vibration by soft mounting both the motor on the block and the block on the bench. Hopefully the belt will smooth out with use as I think the join is causing some lumpiness.
that's a great point John, you can even see it when the join goes over the pulley. I need a long belt for the drill press when I convert that to a treadmill motor and 5ft should just about do both machines. Given that I'll be spending $6 or so for that belt, the HF belt is only going to be $15 more with a coupon. Just have to wait til the wife drives out the the Tri Cities (or Dry $hitties as some people call them!).
From experience, I have found that it is advantageous to use a choke coil on the dc circuit between the MC controller and the Permanent Magnet DC treadmill motor. I found that my treadmill has one so I also installed one on my treadmill motor powered lathe.
The motor will have higher torque at low rpm, will run quieter, and will run with less vibration when the choke coil is used. I understand that the choke coil will also enable the MC controller to last longer.
thanks Forty Niner, I really appreciate that! The one I dismantled had a choke wired in (still have it) but I mistakenly thought it was to filter incoming AC or something similar, doh! After doing some reading it seems like a lot of people recommend using one, particularly to get rid of motor whine, which mine has in buckets. If it does nothing else but get rid of that it'll be worth adding From what I've read (don't have the schematic any more), it sits in series with the black DC wire to the motor - is that how you've wired yours?
Now I just need to find another one for my 2nd treadmill motor that's going on the drill press. Perhaps the local scrap yard will have one?
I have the choke coil wired into the DC circuit, much like your drawing. Except right now I have it wired to the "RED" terminal, but when I use the double pole double throw switch to reverse the motor the coil is then wired to the "BLACK" terminal. It doesn't seem to matter which motor wire it is connected for the choke to work. Let me know if you find that it does matter. My reverse switch is wired between the MC 60 board and the coil. I suppose I could put the switch on the other side of the coil and it would always be in the same place electrically.
great info guys, thanks! I'm really excited to try this out. I got the link belt too, just been busy with other projects.
I'll be adding this to one of the external motor wires, where they're bolted together. I can test it on either wire to see if it makes any difference, although I can't think of why it should as it's role is to increase the total inductance of the motor.
put the choke coil on last night - what a difference! the whine has almost gone, certainly down to a barely noticeable level. no idea on low speed torque as i haven't used it enough to compare. also put the link belt on and the vibration has also almost completely disappeared. i had a very productive Friday afternoon now i just need to find one for the other motor..
Thanks for the amazingly thorough reply Monty, that's a great source of information. I think it would be worth sticking all this in a "how to" sticky post once I'm done as it would be a waste for all the info to be stuck somewhere in my thread.
I think I've addressed most of your points, especially the extra switch to isolate the whole caboodle - that's the first one on the AC line in my sketch on the first page. I'll be using an illuminated switch so it should be easy to see if the controller is energised or not. All the switches I've bought are 110V 15A rated, so that should be enough - the fuse (which I'll be reusing if I can) off the treadmill I scavenged is 15A rated too.
I'm replacing the flywheels with fans mounted to the motor shaft, but if I have trouble with cooling at low speeds I can always add a PC fan and wire it to the 12V supply for the tach.
Almost finished making the adapter hub to mount a 120mm PC fan to Jake's motor. Screwed up the first one because I was tired, but this one fits perfectly. Need to tap a hole and make a set screw then that part is done. After that I need to bore out the pulley to fit and figure out a mount then the lathe motor will be ready for wiring up. I'm not sure how I'll stop chips getting inside other than the chip shield I plan on making for the lathe, but I'll ruminate on that.
I was rereading your post (because I really like your whole thread, with step-by-step updates of what worked and what didn't, by the way). You mentioned the illuminated power switch, which is great, with one caveat: the bulb may fail to light, so don't let it give you a false sense of security. You didn't say what kind of bulb is in use; I would suggest LED as they have the highest reliability and life.
You might be interested in what I am putting into my machine power circuits in addition to your power indicator light: a switch that you have to twist to turn on, and press to stop. It's big and red, and used on a lot of machines. The idea is that when your sleeve gets caught and starts wrapping around the spinning chuck, you can stop the machine really fast by smacking the thing with your free hand, and it won't restart until you twist it again.
Actually the illuminated switch didn't work quite the way intended - it's lit anytime there is power to the box, rather than when the machine is turned on. So I pull the plug out (right in front of me) and coil up the cable when it's not in use. Not a bad idea with kids around, just in case. The next one will have a power switch at the plug, so I'll be able to isolate power to the control without having to unplug it.
I like your e-stop idea, those are really cool switches - they have them on the fume hoods at work. It's definitely something I'll bear in mind for the future.
My kids are grown, so I hadn't thought of that angle. I would consider a lockable master switch for the shop if at all feasible. One option would be "AC compressor disconnect" - a UL rated box with pull-out thing that breaks the circuit. Under $7 at the big orange box. You could have a couple if the circuits are separate.
6. and best of all, cutting resistor R19/ RPS3 (connected to the wiper post of the pot) does away with the need to zero the pot to start the motor. It now starts at the same speed. How cool is that? Even found the same resistor (I think) on the MC40 board from my old treadmill. Woohoo!.
I'm 99% sure that's the one - it's the right no. and it's connected to the white (center) wire of the pot. I haven't done this mod to my MC40 controller yet so it might be a better idea to desolder one end instead