Another Treadmill Motor Speed Controller conversion thread

[silverchips]

So, digging deeper.

Since I don't need a treadmill, I decided to take apart the console to see what was going on in there.

Assuming that the tachometer built into the belt is actually returning input to the driver to maintain speed vs load, then this would be able to maintain spindle speed under load.

Why would I NOT want to use this? It's a frikkin treadmill screen. It won't tell me RPMs or anything like that. It will also, presumably, only keep track of speed as predefined AS a treadmill.
Now, it wouldn't be too difficult to figure out how to add the tack to a spindle but it would never read RPM. It would read MPH. I'd need to add a chart to translate RPM to Spindle speed.

That's all UNLESS, I just abandoned the readout on the console and, instead, just put a tach on the motor (or spindle) and used an exterior display for that.
Given that option I'd just need to figure out the startup routine on the controller board and then either simulate that, or add buttons to make it work like this

All, just to allow the tach to maintain speed under load.

Decisions, decisions.

I highly suggest going down this route, its easy peasy and takes out all the guessing or having to make calculations in your head or having to make a cheat sheet when you position the sensor on the piece you want to know what its actual RPM is at that moment. I've done this with a couple of VFD's to avoid using the motor herz display and having a pulley system effecting the end rpm speed. Really nice to have on a lathe with sensor on the spindle.

https://www.amazon.com/gp/product/B00VKAT8A2/ref=ox_sc_act_title_8?smid=A10ZX1GHP13ZSF&psc=1

 

[Inferno]

I highly suggest going down this route, its easy peasy and takes out all the guessing or having to make calculations in your head or having to make a cheat sheet when you position the sensor on the piece you want to know what its actual RPM is at that moment. I've done this with a couple of VFD's to avoid using the motor herz display and having a pulley system effecting the end rpm speed. Really nice to have on a lathe with sensor on the spindle.

https://www.amazon.com/gp/product/B00VKAT8A2/ref=ox_sc_act_title_8?smid=A10ZX1GHP13ZSF&psc=1

I already have a tach on my TouchDRO but currently it's only on the lathe drive. I don't know that I would ever run the lathe and mill head at the same time so I could use a shared input for that. That way, whichever tool I'm using, I'll have the tach readout on the DRO.
This is starting to seem, possibly, easier.

I do like that device you've linked for a couple other projects though.

 

[Inferno]

Sometimes I do my best thinking when I'm drifting off to sleep.

Something occurred to me. Well, a couple things.

1) The rotational switch for settings wouldn't work because the control panel for the TM controller is momentary push, at best. So to have 10 presets I need 10 push buttons.
2) There's still the slow start thing to contend with which would be a PIA to deal with when I'm trying to thread a hole.
3) The TM motor controller won't return to the set speed each time I restart the motor. Whenever I needed to stop and restart the motor, there'd be a routine I'd have to go through.

Considerations:
1) I could have a rotational switch and have a pushbutton to "engage" so I could set speed 4, for instance, then a pushbutton to send it. This wouldn't be too horrible as the speed selector would always remain in position. Much better than trying to remember which speed button I pushed last time.

2) The slow start isn't an issue on the lathe head. It's a HUGE issue on the mill head. As I said, I use the mill head for threading. The TM controller wouldn't be fun to use for that. If it didn't have the startup lag and slow start then the TM would be far superior to what I do, providing it retained the torque.

3) I thought I could work around this by letting the controller "run" in the background while there'd be an on/off switch for the motor itself. This won't work with the TM controller for the exact reason I want to use it. Once the motor stopped via the on/off switch the tach wouldn't send a signal and the TM controller would error out. It would be near instantaneous.

So, there are pros and cons to consider.

Using a TM controller adds the torque vs rpm curve but loses startup efficiency
Using an alternate controller adds a lot of flexibility but loses the torque curve

 

[Z2V]

2) The slow start isn't an issue on the lathe head. It's a HUGE issue on the mill head. As I said, I use the mill head for threading. The TM controller wouldn't be fun to use for that. If it didn't have the startup lag and slow start then the TM would be far superior to what I do, providing it retained the torque.

As I mentioned earlier I’m using the PWM shown in post #43 and it allows me to start at any preset speed by just pushing the start button, no need to turn knob down and start from zero speed. I’m using the MC2100

 

[Inferno]

As I mentioned earlier I’m using the PWM shown in post #43 and it allows me to start at any preset speed by just pushing the start button, no need to turn knob down and start from zero speed. I’m using the MC2100

Right. I am still leaning that direction.

Can you tell me the loss of RPM (torque) at low speeds?
If I'm using a 1" drill bit on 6061 aluminum, chasing a 7/8" bore, I don't want to be running 4000 RPM when I hit the piece to keep it at 800 RPM while cutting.

 

[Inferno]

So, I've ordered the parts for all three solutions.
I might have said before, it's not about the destination as much as the journey.

Here's what I'm thinking.

The original rheostat controller will work. It won't have the low end torque I'd like (or maybe it would) but I want to build it anyhow. I have that one sitting on my coffee table ready to go.

I have most of the components for the 555 timer circuit. I don't have a huge selection of capacitors though so I'd need to buy those.

I bought 3 LED tach displays from overseas. They won't be here for a while.

I bought the other controller that uses the same concept as the 555 timer circuit. I don't know when it will be here.

So, looking deeper into the treadmill controller, it dawned on me that if I don't use the preset speeds, all I need is THIS



I don't even need the incline part.
So, 4 switch positions. 6 if I count reversing.
The Smithy already has 4 of those. I'd just need to add a speed up/down switch.

This will plug directly into the motor controller. I haven't looked to see what would be displayed or if I'd want to disable the display completely. But this is the EASIEST route, as mentioned above.
Still has the slow start feature.

SO. What if I added an auxiliary box that has the OTHER controller in it. Using the 555 timer circuit (it's on the way) as a convenience controller. It won't have the torque curve in it but could, potentially, be a fast start device.
It might take some relays to keep the controllers separate but it could work as an instant ON/OFF motor controller. So when I press ON, the motor immediately comes to speed.

I probably want to get a bench testing setup made.

I should probably also clean up the machines and metal from my front porch. That's where I do most of my projects in the warmer weather. Autumn is coming up fast.

 

[Z2V]

Well, my mill is 3ph VFD. I’m using theTM setup on a 2x72 belt grinder I usually run at 3500-4000 SFPM. The speed will fluctuate a few hundred under load, that could be fixed by fine tuning the trimpot? IDK. The tach is the one shown above, it fluctuates some also. For my application the small fluctuations are really not a big issue.
I also have a TM on a 4x6 band saw and have had no torque issues at low speed, it has a MC-60 board.
Sorry I couldn’t give you a more direct answer.

 

[Z2V]

What TM controller do you have?

 

[Inferno]

Well, my mill is 3ph VFD. I’m using theTM setup on a 2x72 belt grinder I usually run at 3500-4000 SFPM. The speed will fluctuate a few hundred under load, that could be fixed by fine tuning the trimpot? IDK. The tach is the one shown above, it fluctuates some also. For my application the small fluctuations are really not a big issue.
I also have a TM on a 4x6 band saw and have had no torque issues at low speed, it has a MC-60 board.
Sorry I couldn’t give you a more direct answer.

Your answer works.
I can stall my bench grinder if I try and it uses a "regular" motor.
The MC-60 board is a different animal. I kind of like the way they are portrayed. When you are dealing in "free" treadmills, you get what you get.

As noted above, I have two MC-2100 boards. One new, one used.

 

[Z2V]

I guess I overlooked when you mentioned you had the 2100.
Honestly, on my grinder I actually liked the MC-60 board better than the 2100. The MC-60 was strong as hell, no fluctuations at all. I put it on the band saw. If I come across another 60 I’ll probably ditch the 2100