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  • DougLA
    replied
    Nice!

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  • tool fan
    replied
    Wow that's quite a large bowl!   Your experience with the SCR controller is what I remember.   My conclusion was that it was about the same as the already packaged DC 51.  

    Here's my latest project.   I actually found two of these old Rockwell lathes with what look like original Preston Leland  3/4 HP 3 phase motors.  

     

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  • DougLA
    replied
    Thanks Rory.

    Out of interest I had tried this controller with my lathe which uses same model treadmill motor as in last post and is set up with a KB Electronics controller. I have been roughing out wet beech into 16" bowl blanks and it was easy enough to temporarily wire in new SCR controller.

    Comparing the two, my present set up does work hard turning these large items but is quite satisfactory. Using the new SCR controller it is much easier to stall, I presume as no voltage or current compensation under load. I'll see how it works doing lighter, smaller stuff either again temporarily wiring it back in to present lathe or set up with my unused Beaver 3400. Might be after the summer before get a roundtoit. As per Braz-in-the-Peg I guess it will be fine with smaller items.

    Doug
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    Last edited by DougLA; 06-26-2020, 06:35 AM.

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  • tool fan
    replied
    I like the setup, very tidy and I like how you have incorporated a voltmeter. I f you find that it produces enough torque at low speed for your Beaver lathe I will be copying you. Thanks for sharing the details.


    Sent from my iPhone using Tapatalk

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  • DougLA
    replied
    tool fan & Braz-in-the-Peg,

    I've set up one of the 10,000 watt SCR's as a self contained controller in a recycled 4X6X6" PVC junction box and incorporated a voltage meter and reverse polarity DPDT switch. Same regulator as Braz-in-the-Peg a few posts back. (10000W AC110V 220V 75A SCR Voltage Regulator Speed Controller via eBay) As he said maximum voltage he calculated does appear to be 130 volts at least on motors I tried it on. Not sure what I will do with it - if nothing else, useful to have a variable DC voltage power supply. Must say it is not as "smart" a controller as treadmill MC-60 or KB electronics controller that I am presently using on my lathe - as it does not have any voltage or current compensation when under load. Guess would be OK with a smaller lathe and I'll likely rig it up with my old Beaver 3400 I have on a shelf.

    Just threw together a Flickr album:
    https://www.flickr.com/photos/767624...57714856974796
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  • tool fan
    replied
    Originally posted by DougLA View Post
    Tool fan,

    Looks good and no doubt a fun project. My opinion would be if you want some idea of rpms - it's there.

    I have a 10,000 watt SCR on the way from Amazon. Hope to gear up with a treadmill motor on my Beaver 3400 as a 2nd lathe or perhaps a bandsaw. Looking forward to messing around with it and answering question as to how many DC volts this controller puts out.

    Doug
    Thanks Doug, It was fun and I think I should have kept the heart monitor hardware so I can measure that while I use the lathe.

    I sure hope the 10,000 watt SCR works. Free treadmills are becoming a scarcity around here. About a year ago I could pick one up whenever I needed one. Now, they are gone within a couple of hours of posting. Right now I have loads of the little motors but no controllers that can deliver enough power to be effective. Keep us informed when you try the one you ordered.

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  • DougLA
    replied
    Tool fan,

    Looks good and no doubt a fun project. My opinion would be if you want some idea of rpms - it's there.

    I have a 10,000 watt SCR on the way from Amazon. Hope to gear up with a treadmill motor on my Beaver 3400 as a 2nd lathe or perhaps a bandsaw. Looking forward to messing around with it and answering question as to how many DC volts this controller puts out.

    Doug

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  • billh
    replied
    Personally, I couldn't care less about a speed display. I set the speed to what I think is appropriate for what I am doing.
    billh

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  • tool fan
    replied
    A few weeks ago I picked up a small metal lathe, that I believe was used to restore commutators. The badge says Lanagan, but I could not find any information about this lathe. Anyway, I had a circuit board from a treadmill that was quite different from the MC 60. It was actually 2 separate boards and it required the display to function. I parred it down to the basics and ended up with this. It starts at 5 mph on the display or 80 rpm at the spindle. Each click at the low end is about 80 rpm, however it is not linear and at the high end each click is ~ 40 rpm at the spindle. The effective turning range is 80 to 3650. There is currently a 2 1/2" drive pulley and 4" pulley on the spindle. A larger spindle pulley would be better.

    The point being is, if you can live with the display, this is another treadmill that can be used to achieve variable speed. Here's a video of it running



    Attached Files
    Last edited by tool fan; 05-28-2020, 10:00 AM.

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  • DougLA
    replied
    Braz, Great that your treadmill motor/controller set up works for you - that's what counts.

    Generally and my understanding from a non expert's point of view, is that to take advantage of full power from a fast treadmill motor, one needs to be able to "gear" down post motor rpms with use of pulleys. Gearing down with step pulleys and/or a jackshaft in affect acts as a "torque multiplier".

    Power = Torque x motor rpm. Thus need to run motor at as close to full speed as possible to achieve max. power.

    For example with my Craftmaster the motor's top speed at 180 volts is 3400 rpms. The motor's 3400 rpms is "geared down" to a speed of 2000rpms at jackshaft. In "low gear" with large pulley on jackshaft step pulley to small pulley on lathe spindle it is further geared down to a top spindle speed of 1000 rpms. For highest lathe spindle speed possible I switch to "high gear" with largest pulley on jackshaft and smallest pulley on lathe spindle yielding a lathe spindle top speed of 3000 rpms, again at 180volts.

    To lower spindle speeds in any particular "gear" the controller is used to turndown volts to motor (thus rpms), but with a consequent loss of power. When turning a 16" wet and heavy outboard blank I use "low gear" with step pulleys with capacity to rough out at a spindle speed of 150 rpms. (in this situation controller output is at 30V with a motor speed of 500 rpms) Turning pens I place in "high gear" with spindle range of 475 to 3000 rpms (30 to 180V).
    Last edited by DougLA; 05-13-2020, 08:30 AM.

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  • Braz_in_the_Peg
    replied
    I won't try testing the voltage since my multimeter only goes 10Volts for testing DC power but from the research I did it doesn't hurt the motor if running at less than 90volts which is what the potentiometer does anyways. In the end, as long as the motor and lathe perform as you need, then you're good to go!

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  • tool fan
    replied
    Originally posted by DougLA View Post
    My cause for concern re voltage ouput, as you describe, was because I had read that some that use this 10000watt controller converting 110V AC to DC were only getting a disappointing max of 60V DC output. (Measured at DC + and - wires leading to motor armature.)

    The MC60 controller that I used with a drill press conversion (by my voltmeter) produces a max of 90V DC. If correct ~133 volts by your calculations is impressive.

    From what I understand this 10000watt controller would not work with North American household 220-240AC (split phase). However my KBMD controller on lathe does have option to handle 220 AC input and I have dialed specific trimpot to a max of 180V DC output which yields a motor speed of 3400rpm. (Motor speed proportional to voltage.)

    As one non-expert to another I will say, take care if decide to measure DC voltage output with a voltmeter!!

    I'm impressed with your set up and am considering rigging up a Beaver 3400 with a treadmill motor using a controller as yours. Free treadmills around here are rare finds on Kijij and even more so with Covid19.
    I just checked an MC 60 control board and yes it produces a maximum of 90 DC volts. The smaller DC 51 control board can produce a maximum of 110 DC volts, but only draws a maximum of 4 amps or 440 watts. The MC 60's will pull up to 20 amps or 1800 watts. So, by my calculations, the DC 51 controllers are good to 1/2 hp and the mc 60's to 2.5 hp.

    If what Braz in the Peg has made can actually pull 75 amps, it should be good to 13 hp. However it's hard to imagine that kind of amperage with what looks like 14 gauge wires and a simple 110 ac input.

    As I think as I write, the advantage of the vfd is the 3 hot leads each drawing only 2 or 3 amps. The low amperage means that the wiring does not have to be massive. The one that I have on the Delta draws about 3 amps on each lead which equates to 2,200 watts or 3 hp and that is more than adequate for the 1/2 hp motor.

    I just locked the spindle and cranked up the frequency. If ammeter on the vfd is accurate it went to 15 amps before it overloaded.
    Last edited by tool fan; 05-12-2020, 01:31 PM.

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  • DougLA
    replied
    My cause for concern re voltage ouput, as you describe, was because I had read that some that use this 10000watt controller converting 110V AC to DC were only getting a disappointing max of 60V DC output. (Measured at DC + and - wires leading to motor armature.)

    The MC60 controller that I used with a drill press conversion (by my voltmeter) produces a max of 90V DC. If correct ~133 volts by your calculations is impressive.

    From what I understand this 10000watt controller would not work with North American household 220-240AC (split phase). However my KBMD controller on lathe does have option to handle 220 AC input and I have dialed specific trimpot to a max of 180V DC output which yields a motor speed of 3400rpm. (Motor speed proportional to voltage.)

    As one non-expert to another I will say, take care if decide to measure DC voltage output with a voltmeter!!

    I'm impressed with your set up and am considering rigging up a Beaver 3400 with a treadmill motor using a controller as yours. Free treadmills around here are rare finds on Kijij and even more so with Covid19.

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  • Braz_in_the_Peg
    replied
    I'm no expert in electronics either but the controller was listed as 110V-220V so I figured I could use it for 110V since the connections looked like it should hook up easily to 110V. At some point I just figured I would just give this try and see if it would actually work.

    I never measured the voltage output and I was concerned about this because many videos I watched said you need that 90V output (depending on your motor but most treadmill motors need around this voltage). That's one of the reasons I went with the 10000W controller. I found an online calculator (https://www.inchcalculator.com/watts...ts-calculator/) that lets you input watts and amps and spits out the voltage produced. For this controller it has 10000W and 75Amps which calculated out to 133.33V so I figured I should be good.

    The power (which I think is a measurement of torque) the motor produces is more than adequate for turning especially when the rpms are increased. You can notice the reduced torque at lower speeds but then again you aren't taking heavy cuts either at the lower speed. You can also adjust your pulley size to get the increase in RPMs thus increasing the torque. With my setup I measured the lowest RPM I could get and it was 50RPM so I figured I would change the pulley size if needed but so far I haven't had to. I bought one of those cheap Tachometers off eBay to measure the RPM.

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  • DougLA
    replied
    Originally posted by billh View Post
    Our power is not 2-phase, it is 220 (actually 240V) split-phase. This can turn into a semantics argument but the power is single-phase. The rectifier would have been necessary even if the controller was the 120V model since it still produces AC, not DC. I suspect the pot modification has a lot to do with the motor characteristics.

    billh
    Bill,

    Thanks for info. Like said I know little about electronics and perhaps one should not believe everything they read!

    Suffice to say 220V AC in other countries is not the same as what we call 220V AC in North American house current.

    Yes I did not mean to imply that the rectifier is needed for anything more than converting AC to DC.

    Doug

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