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  • #91

    Re: Variable speed

    Originally posted by iamtooler View Post

    So now we can ask an expert; how does it compare to your DC systems?
    In terms of torque, about the same. However,the VFD and 3 phase motor combination is superior in many other respects: braking, ability to flip between forward and reverse without stopping, ability to adjust settings like torque and monitor amperage. The downside is that VFD's and 3 phase motors are not free. I would say that for small lathes, like the Beaver 3400, a decent treadmill motor and controller are perfectly adequate. For larger lathes, VFD's and 3 phase motors are definitely a better route to go.

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    • #92

      Re: Variable speed

      I just converted my Jet 1442 lathe to variable speed using a treadmill motor. I'm really happy I converted the lathe. It gives alot more options than I had before. People give away treadmills all the time so if you can wait until the pandemic is over, get yourself a treadmill and then order the parts off ebay for the variable speed. I turn all kinds of sizes of bowls on my lathe and have not found any issues with torque. I will say there is less torque at the lowest speed (I have mine setup to spin at 50 rpm), but if I'm turning anything at that low of a speed it's not something where I'm taking heavy cuts anyways. I removed the weight as it's not really needed. It's on treadmills just to keep the track moving and allow the person to slow down gradually.

      This video on youtube is by far in my opinion the best explanation of how to convert your lathe motor to variable speed. He even lists the parts off ebay that he used but I ended up getting the 10000watt regulator to be sure I had enough power going to the motor. You have to switch out the potentiometer on the controller as well. I can't find the link to the one I purchased but I think he lists it in the video. I also added the reverse switch but make sure you can lock your spindle if you're using reverse! Some people will use the treadmill controller but none of the treadmills I picked up had the correct board and in the end I'm glad I bought the controller off ebay since this allowed me to put everything into a small box and mount it on top of the headstock.
      https://www.youtube.com/watch?v=_NmAFZMAfH8

      Here's some links to the parts I bought:

      This regulator has the build in fan which I removed and mounted at the back of the black box which holds all the electronics.

      https://www.ebay.ca/itm/10000W-AC110...MAAOSw5kdemA8F

      https://www.ebay.ca/itm/2PCS-50A-100...72.m2749.l2649

      https://www.ebay.ca/itm/2PCS-6-Pin-3...72.m2749.l2649

      https://www.ebay.ca/itm/40mm-Outside...72.m2749.l2649

      I had to make a new motor mount (used a door hinge) and set it up so the motor still hangs off the headstock and everything is contained on the headstock like before since my head stock rotates. My lathe had the reeves variable speed drive so I removed the whole thing and added a locking ring to prevent the pulley from opening up. My top RPMs are less than I had before but I can change out the pulley on the motor if I wanted to get more speed but so far even turning pens has been no problem. I also added a cooling fan with a filter to side of the motor and it blows air through the motor and keeps it nice and cool which works great. The motor had a fan on it but it was at the wrong end for my setup and would have been in the way. The filter helps prevent too much dust from getting into the motor. You can see the small black box which houses all the electronic parts and connections (I added some rare earth magnets to the bottom to prevent it from sliding off the headstock). I also added a small fan in the box to make sure the bridge rectifier stays cool and it has been working great so far (the fan was in the speed controller I bought and I removed it and mounted to the back of the box). I also added the ferrite ring which smooths out the power a little. I also used the original power switch to power the control box.

      I had been wanting to do the conversion a couple years ago but had no understanding of any of this and once the need for variable speed over came my unwillingness to learn and figure it all out, I just did alot of research and in the end it really wasn't that difficult and the cost wasn't much if you can get a free treadmill. I ended up getting 5 treadmills for free and even sold one of the motors because it wasn't a DC motor. I have now made 3 different variable speed devices (my wife carves and wanted a couple variable speed sharpeners).

      Hope this helps.
      Dwayne
      Attached Files
      Last edited by Braz_in_the_Peg; 05-09-2020, 10:07 PM.

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      • #93

        Re: Variable speed

        Originally posted by tool fan View Post

        In terms of torque, about the same. However,the VFD and 3 phase motor combination is superior in many other respects: braking, ability to flip between forward and reverse without stopping, ability to adjust settings like torque and monitor amperage. The downside is that VFD's and 3 phase motors are not free. I would say that for small lathes, like the Beaver 3400, a decent treadmill motor and controller are perfectly adequate. For larger lathes, VFD's and 3 phase motors are definitely a better route to go.

        tool fan:

        Nice job with the VFD conversion on older Deta lathe. I agree re advantages you list of VFD over DC. Biggest advantage in my mind is ability to brake quickly and easier to reverse. I went so far as to place a shield over my reverse switch on KBMD 240D controller so as to discourage inadvertently reversing while DC motor running. Discussed this a bit back on my Craftmaster lathe conversion to a large treadmill motor using KBMD 240D controller which does have all the bells and whistles re adjustments. These controllers aren't cheap new and probably a prime motivation for my going the treadmill route was I spied the used KB controller plus large treadmill motor both at a good price. (Suitable 3 phase motors are rare finds on Kijiji round here.) If had to do it again I think I would choose the VFD route for a larger lathe. Don't expect to sell my lathe anytime soon but I do wonder if a VFD would also have better resale value. Sometimes I think I do things just to see if can. Don't get me wrong - I'm very happy with present lathe setup!

        Is / will the 1/2 HP 3phase motor be a little underpowered for large bowls? Presume still being able to adjust belt on 4 step pulleys will help. Perhaps no need for more HP if don't use outboard side? Notice motor is TEFC - that's good.

        ​​​​​​Doug
        Click image for larger version

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        Attached Files

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        • #94

          Re: Variable speed

          Originally posted by Braz_in_the_Peg View Post
          I just converted my Jet 1442 lathe to variable speed using a treadmill motor. I'm really happy I converted the lathe. It gives alot more options than I had before. People give away treadmills all the time so if you can wait until the pandemic is over, get yourself a treadmill and then order the parts off ebay for the variable speed. I turn all kinds of sizes of bowls on my lathe and have not found any issues with torque. .........
          ...........I have now made 3 different variable speed devices (my wife carves and wanted a couple variable speed sharpeners).

          Hope this helps.
          Dwayne
          Dwayne,

          Thanks for posting re your lathe conversion with this DC 10000 watt controller and a treadmill motor conversion. Very interesting and good job. Looks like its made a big improvement to your lathe. I too have spent time researching their use. Had posted (#86 above) querying people's experience with this. Tool fan had tried similar controllers but with much lower wattage rating than yours and didn't have much luck. Let us know if any issues develop.

          Interesting that a controller like yours was designed for use with a 220v ac single phase current as used in other parts of world. (Our 220 is 2 phase.) Hence require bridge rectifier to convert to DC and potentiometer modification. I have very little electronics knowledge, but nowadays with resources on internet as u-tube and forums like this - makes these sort of projects much more doable!

          Doug
          Last edited by DougLA; 05-10-2020, 08:11 AM.

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          • #95

            Re: Variable speed

            Dwayne,
            Followup question, wonder if you have measured your controller setup's top DC voltage output? Is it 90v or higher?
            Doug

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            • #96

              Re: Variable speed

              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

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              • #97

                Re: Variable speed

                Originally posted by DougLA View Post


                tool fan:

                Nice job with the VFD conversion on older Deta lathe. I agree re advantages you list of VFD over DC. Biggest advantage in my mind is ability to brake quickly and easier to reverse. I went so far as to place a shield over my reverse switch on KBMD 240D controller so as to discourage inadvertently reversing while DC motor running. Discussed this a bit back on my Craftmaster lathe conversion to a large treadmill motor using KBMD 240D controller which does have all the bells and whistles re adjustments. These controllers aren't cheap new and probably a prime motivation for my going the treadmill route was I spied the used KB controller plus large treadmill motor both at a good price. (Suitable 3 phase motors are rare finds on Kijiji round here.) If had to do it again I think I would choose the VFD route for a larger lathe. Don't expect to sell my lathe anytime soon but I do wonder if a VFD would also have better resale value. Sometimes I think I do things just to see if can. Don't get me wrong - I'm very happy with present lathe setup!

                Is / will the 1/2 HP 3phase motor be a little underpowered for large bowls? Presume still being able to adjust belt on 4 step pulleys will help. Perhaps no need for more HP if don't use outboard side? Notice motor is TEFC - that's good.

                ​​​​​​Doug
                Click image for larger version  Name:	fullsizeoutput_9b8.jpeg Views:	0 Size:	2.10 MB ID:	1282849

                Doug, the KB electronic controllers are the best DC motor controllers that I have encountered. They are virtually the same as a VFD with the exception of forward/reverse switching. Like you I enjoy the challenge of doing these conversions. I seek out old lathes, clean them up, add a variable speed drive and resell them. Its a hobby for me that has enabled me to acquire a couple of shops full of tools.

                In my opinion the second best option for DC motor control is an MC 60 control board found in older treadmills.

                A few years ago the DC 51 controllers worked just as well as the MC 60, but they are not the same now and function okay for small motor projects. I never had any luck using an scr with bridge rectifier, but it was only rated for 400 watts when I tried it.

                The 1/2 HP motor may be a little underpowered, but it is 1725 rpm, so the low range is 0 to ~800. It seems to have plenty of torque. If I had a 1 HP I would have used it.

                The huge advantage of treadmill motors and controllers is that they are free, a big consideration if resale is the goal.
                Last edited by tool fan; 05-10-2020, 09:34 AM.

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                • #98

                  Re: Variable speed

                  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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                  • #99

                    Re: Variable speed

                    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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                    • Re: Variable speed

                      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.

                      Comment


                      • Re: Variable speed

                        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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                        • Re: Variable speed

                          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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                          • Re: Variable speed

                            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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                            • Re: Variable speed

                              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.
                              iamtooler likes this.

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                              • Re: Variable speed

                                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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