DC conversion on lathe.

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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid » Tue Apr 28, 2015 8:47 am

Thanks Torch! Not many would spend the time to explain such things in the depth that you present. Just wanted you to know you're appreciated.

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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid » Tue Apr 28, 2015 8:54 pm

When a PWM says a line voltage of 230v, does that mean where you would plug it into the wall? Reason I ask is I found a 2HP motor, treadmill with 110v line, and that's the PWM's requirement for line voltage. To me "line voltage" in house wall plug in!

Torch
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Re: DC conversion on lathe.

Post by Torch » Tue Apr 28, 2015 9:14 pm

Yes, line voltage refers to the AC supply voltage. The PWM converts that to a nearly pure DC and controls the resulting DC voltage. Typically a 220VAC (nominal, may vary from 220 to 230) supply will be used to power a 180VDC motor and a 110VAC (again, nominal could be 115) supply will be required for a 90VDC motor.

I'm a bit confused though. You say the treadmill has a 110VAC plug, but the PWM controller lists the line voltage as 230VAC? 220VAC is common for wall outlets overseas -- much of Europe, Japan, Australia, etc. Maybe the controller is designed to handle any voltage from 110 to 230 to simplify international sales. Try googling a part number of the controller if you can find one to see if you can find the specs.

Since electrical HP and Watts are both measurements of power, and since watts = volts x amps, there is an advantage to 220 volt machinery: it requires half the current to achieve the same power, so there is less power loss through a long run of supply wiring. Or the wiring can be lighter gauge, if the run is acceptable.

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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid » Tue Apr 28, 2015 9:29 pm

Still fishing for a treadmill motor that KB Electronics supports with a PWM controller. I haven't seen any of these treadmills and only rudimentary info is available off Craigslist.

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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid » Wed Apr 29, 2015 7:40 am

Going to pick up that 1.25 HP treadmill this morning. Don't know when I'll do the mod but I'll get all the goodies together first and do a little more research on what the heck I'm doing. Also know I'll have to select pullys and belts, digital readout, etc. Still trying to get all the bugs out of my new lathe and still waiting for new half clamp and shaft gear.

Torch
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Re: DC conversion on lathe.

Post by Torch » Wed Apr 29, 2015 9:53 am

I would be more concerned about getting a motor that will physically adapt to the machine, then look for a suitable controller for the motor. Just my 2¢.

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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid » Wed Apr 29, 2015 12:40 pm

Torch wrote:I would be more concerned about getting a motor that will physically adapt to the machine, then look for a suitable controller for the motor. Just my 2¢.
Pretty sure this motor will fit. Picked the up treadmill this morning and stripped it down! Not bad for $60 and I made sure everything worked before I bought it. Gonna need a reversing polarity switch or better still a reversing pot and a digital read out. Probably won't need/want the control panel but I saved it and everything else I could salvage. I even kept the box frame which will make a good sturdy general purpose bench of some sort. Have to be an outside bench though cause not room inside shop.

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Torch
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Re: DC conversion on lathe.

Post by Torch » Wed Apr 29, 2015 2:58 pm

Nice motor -- 14 amps DC is a bit much for the KB products. Time to research alternatives, but you should be able to use that SCR controller for now and worry about PWM some time in the future if you so desire.

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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid » Wed Apr 29, 2015 3:35 pm

I was looking at KBMM-125 controller. What do you think about it? Here's a link,

https://www.galco.com/buy/KB-Electronic ... 125#bottom

And, (See pg. 9)
http://www.kbelectronics.com/manuals/kb ... manual.pdf

Torch
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Re: DC conversion on lathe.

Post by Torch » Wed Apr 29, 2015 6:24 pm

I'm not sure what the advantage is. It is an SCR controller, and you have a working one of those already

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wsippola
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Re: DC conversion on lathe.

Post by wsippola » Wed Apr 29, 2015 6:34 pm

You may as well use the controller that came with the treadmill. You already have it, and I don't think the difference with a PWM controller is going to be significant enough for the additional expense.

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LX Kid
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Re: DC conversion on lathe.

Post by LX Kid » Wed Apr 29, 2015 6:47 pm

Torch wrote:Hopefully you can just use the one that comes with the treadmill, but if you are willing to spend as much as $200 on a controller, give serious consideration to a PWM controller rather than an SCR controller. Smoother, quieter and more low speed torque. And, IMHO, torque is more important than horsepower.

I was going on what you had suggested above and is why I was considering a PWM Controller. I do intend to use the SCR Controller for now though. When and if I start this mod anytime soon it would be nice to do it all at once even though it would be a simple swap out.

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