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  • Voltage Supply?

    If the supply voltage for say a Leblond 16" Lathe reads 460 and 3 phase on the machine's nameplate, can this be run on regular household electric supply with a 3 phase converter?

  • #2
    No, you have to supply the rated voltage... Sorry!

    Chris

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    • #3
      yeah I'm a dumby when it comes to electricity. so I guess I'm limited on the size of machine I can run in my garage to anything that can be run on 220?

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      • #4
        You're limited to anything 220V unless you find a cheap old (and big!) 220/460v stick welder to use as a transformer to get from 220 to 460 before the phase convertor? Otherwise a 3-phase 460v VFD can be hacked to fool it into thinking it has 460ish when powered from 220 - a simple mod' if it has 2 banks of DC bus capacitors (i.e. is oldish and largish), I've done it for my 415v Holbrook to run it from 240v using and old ABB ACS300 series VFD - it means derating it by 30% though, so I've used a 5HP rated (3.5KW) VFD for the 3HP (2.2KW) motor. A competent electronics tech' should be able to do it in 10 minutes or so

        Dave H. (The other one)
        Rules are for the obedience of fools, and the guidance of wise men.

        Holbrook Model C Number 13 lathe, Testa 2U universal mill, bikes and tools

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        • #5
          I thought the standard answer here would be to buy a suitable VFD?

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          • #6
            Probably the cleanest solution is to pull the present motor, put in a 240V 3-phase motor, and use a VFD to get the 3-phase power. That may not be the cheapest way out, but I don't know enough to come up with any cheap home-grown solutions so it's probably what I would do. What size motor do you need? 3hp?
            ----------
            Try to make a living, not a killing. -- Utah Phillips
            Don't believe everything you know. -- Bumper sticker
            Everybody is ignorant, only on different subjects. -- Will Rogers
            There are lots of people who mistake their imagination for their memory. - Josh Billings
            Law of Logical Argument - Anything is possible if you don't know what you are talking about.
            Don't own anything you have to feed or paint. - Hood River Blackie

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            • #7
              Recent thread on Practical Machinist suggests that a 440v 3ph motor will
              run fine on a 220v 3ph output VFD at 30hz with a power output ~1/2 the
              rated horsepower of the motor. If you can stand the power output drop
              this is one option. You would have to be able to tolerate the motor rpm
              as well perhaps by belting etc. Running the Hz of the vfd up seems to drop
              the power output of the motor further as well but the thread got a bit confusing
              on that point. This is a 440v motor connected as 440v but driven by a 220V VFD
              Ref: http://www.practicalmachinist.com/vb...-motor-232914/
              and the original starter thread: http://www.practicalmachinist.com/vb...-motor-232914/

              For a Leblond lathe of that size the motor size may make this approach moot, depending on how much cutting you are doing
              with it. Most lathes use only a fraction of the motor power, but cutting a 0.25" DOC off a an 8" cylinder would not likely be
              feasible with the above approach.
              Last edited by sch; 10-08-2011, 09:32 PM.
              Steve

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              • #8
                Check to see if it is a 220/460v motor, you will have to change the overloads and fusing, although if it is possible and using a VFD you will not need the O/L's.
                The wiring guage should also be checked.
                Twice the current on 220v.
                The control voltage is most likely 120v, it would not be hard to supply this.
                Max.

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                • #9
                  Yes you can do it. I did it for a friend 2 years ago
                  Find the KW rating of the motor
                  Lets say it is 6 KW.That makes it about 8 HP
                  You will need to find a surplus of about 10 KW transformer.
                  ( needs to have a larger rating than the motor )
                  This transformer would be single phase 480 to 240. ( not a 3 phase trans ! )
                  We found one at a used equipment outlet for 100 bucks.
                  Wire it backwards 240 stepup to 480 and be sure to fuse for the full KW rating.
                  Now get a 480 volt VFD , also larger than the motor ( + 30 % )
                  Even though they have 3 phase input labels, they will convert a single phase input if they have the capacity ( Like 30 %).
                  You may have to rotate the input terminals ( like 1 & 3 instead of 1 & 2 ) in order to find the largest internal Caps and the best output.
                  We found a used 10 K Hitachi VFD for 150 bucks and it is superb.
                  The only issue is the auto break on my friens lathe sometimes interfers with "ramppdown" and he gets a fault. But , that is peanuts
                  Rich

                  PS I differ with the comment on using 220 Volt. You only get 25 % power, not 50 percent. Half voltage gives half amperage= 1/4 KVA
                  Last edited by Rich Carlstedt; 10-08-2011, 09:51 PM.

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                  • #10
                    http://www.drivesdirect.co.uk/Produc...ers240_415.htm

                    Phil

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                    • #11
                      Originally posted by Putch
                      If the supply voltage for say a Leblond 16" Lathe reads 460 and 3 phase on the machine's nameplate, can this be run on regular household electric supply with a 3 phase converter?
                      UK phase converters like the 'Transwave' usually incorporate a boost transformer.
                      http://www.powercapacitors.co.uk/Pow...Downloads.html

                      It's also possible to re-wire many motors for lower voltage. Star/Y to Delta link are common in the UK, but you can also often convert motors without them; http://bbs.homeshopmachinist.net/sho...t=motor+rewire
                      Paul Compton
                      www.morini-mania.co.uk
                      http://www.youtube.com/user/EVguru

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                      • #12
                        Originally posted by philbur
                        Drives Direct is pretty proud of those. Too bad there don't seem to be
                        any equivalents available directly in the US. $500+ is fairly steep for
                        a 1 HP drive. They don't seem to have a direct order website, at least
                        when I prowled around on that site last year. For US types, this is the
                        continental equivalent of the 115vac in 230v 3ph out VFD available in
                        the US. Not sure a 16" Leblond has a 3hp motor, suspect at least 5hp,
                        even 7.5. Dunno, OP hasn't said, so likely the Drives Direct VFD would
                        not suit anyway and the 3 HP VFD pushes $1000.
                        Boost xfmr probably the cheapest route, if suitable can be found
                        and potentially heavy SOB though.
                        Steve

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                        • #13
                          If you stay with the three phase, 460 Volt motor, getting the proper or improper Voltage/current/phases for the motor is only part of the problem. Chances are there is also some control circuitry and it probably runs on 230 or 115 Volts. Contactors, indicator lamps, etc. You need to look at the total wiring, not just the motor. Actually in any case, you need to look at the total situation.
                          Paul A.
                          SE Texas

                          Make it fit.
                          You can't win and there is a penalty for trying!

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                          • #14
                            You said the *machine* plate said 460.........

                            Look at the MOTOR plate to be sure it is NOT a 230/460 motor, which would solve many problems directly

                            You would need also to check the control coil voltages, and see if there is a transformer, which also might have a tap for 230
                            1601

                            Keep eye on ball.
                            Hashim Khan

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                            • #15
                              Thanks guys! This has been real helpful - I think! All this electronics talk is over my head but I guess when I get into it it may be more simple than I imagine.

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