Lab-Volt mill conversion - (attn Marty)

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Rex
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

Systemslave, that was me that was having trouble with the C11. Marty was helping me with it.
Your advice may be what I need to get me past the "hump". Much appreciated. I'll try to revisit that project next week when I'm back at the shop.
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Re: Lab-Volt mill conversion - (attn Marty)

Post by systemslave »

Sorry for my confusion, but I hope it can be helpful. It sounds to me like your board is protecting you.
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

LOL Yeah, most likely.

Are you using Mach3 with yours? I have not attempted to configure Mach3. When the board failed to light up I checked my connections, then checked the RS232 output for signals, then walked away from it to work on other projects.
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Re: Lab-Volt mill conversion - (attn Marty)

Post by systemslave »

I use LinuxCNC. I love the 3D feedback on the screen, and it is super easy to configure. Aside from that it is free and arguably a little faster than Mach. I know that there are religious wars between followers of Mach and followers of LinuxCNC. Let me say that I believe them both to be great options and I don't want to join the wars.
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Rex
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

I actually have both set up on the PC for this mill.
I don't know enough to have a preference. I figured I'd get it running on one (probably Mach3) and then see if I can get it running on the other.
systemslave
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Re: Lab-Volt mill conversion - (attn Marty)

Post by systemslave »

Well if you decide to test it with LinuxCNC I will be glad to assist. The first run on my machine was a pencil mounted in the spindle (spindle speed 0). It sounds like you might be able to do that now. It makes a kind of glorified plotter.
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Re: Lab-Volt mill conversion - (attn Marty)

Post by mikeehlert »

"Oh. I was wiring away while leaning on the cabinet and got a nice jolt of current. The machine had not seen power for a week. And I'm pretty sure I shorted the capacitor after the last power application. I just put a screwdriver across the screw terminals on the top of the capacitor. Do I need to do something different?"

Forgive the stale response but this can be kind of important. Capacitors hold residual charge and/or "gain" charge due to temperature changes. My advise is to always leave a spring clip connected jumper across the capacitor until you are ready to power up. A "third" lead clipped to the power switch will keep you from burning up the power supply.
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Rex
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

Probably a good idea.
In this case the culprit turned out to be a shorted power switch on an adjacent drill press.
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Re: Lab-Volt mill conversion - (attn Marty)

Post by oldvan »

Bleeder resistors across electrolytics can be cheap lifesavers.
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Rex
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

For us non-EEs, how do you do that?
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Re: Lab-Volt mill conversion - (attn Marty)

Post by oldvan »

This can get you started in the right direction:

https://en.wikipedia.org/wiki/Bleeder_resistor
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

Back to the Zombie Thread. After letting it sit for most of the last year, I drug this mill out and booted the PC to try to find a pulse. A local guy offered to provide phone support.

So I had it all hooked up, and nothing would move. Since then I have carefully configured Mach3. Hasn't helped, but I did run across something I could not resolve. In an effort to reduce thenumber of variables, I tried to disable the E-stop in the software. Can't seem to get it to stay unchecked.

Independent of that, my friend suggested I probe the driver input with 5 volts to the step pin on the drive boards. I did that, using a 1000-ohm resister to limit the current. Nothing moved. tried that on all 3 boards.

At that point I measured the voltage from the transformer. I am reading 10 volts AC at the big capacitor terminals, but only 7.5 volts DC at the output to the drives. The DC should be higher than the AC input, as i understand it.
That 7.5 volts hardly seems like enough, though I have no specs on these steppers. They are small NEMA-23 units, about as long as they are wide. I am sure they are under 100 oz-in torque.
Marty, did you ever try to find specs on the steppers on your Lab-Volt lathe?

So my project for this week is to try to find out what the power supply output should be. Failing that, I need to figure out, if possible, what the steppers need to motivate them. I do have a couple of Power supplies in 12V and 24V on hand for other CNC conversions. I would prefer to use the OE setup if possible.

If I can figure that out, I'm back to tickling the steppers.

Any thoughts on this, please share.
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