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  1. #16
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    Quote Originally Posted by Michael G View Post
    Yes, but how are you going to get 4kW out of the VFD if you can only put 2.2kW (10A plug) or 3.3 kW (15A plug) into it - and that is not taking into account losses within the VFD. If the Variator works you are better off putting the biggest single phase motor you can drive. While you can use a 4kW VFD you can't get more out of them than you put in and last time I looked (many years ago) the conversion efficiency was something like 80%, so if you are feeding 3.3kW in, you are likely to only see a bit over 2 1/2kW out. Michael
    That 4kW unit would work fine. If you can feed it. As the Chipmaster has a 3HP motor it only needs 2.2kW anyway, so no real dramas there. I'd hook it to a 15A supply and see how it goes. Only time I see problems is very deep cuts on big work pieces that require all the HP the motor can produce, and how often does that happen? Also these lathes have a clutch so it's less strain on things getting a spindle with workpiece moving from a dead stop. I hate using lathes without clutches now both of my main ones have a clutch. Not sure what your wiring access is like but running a 20A circuit is another possibility. Easy to have done and only needs 4mm wire, same as used for a stove. I'd get true 415V 3 phase but this looks like a very viable alternative, as long as that inverte is any good. PDW

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  3. #17
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    Quote Originally Posted by Stustoys View Post
    1 5KW VSD VFD Inverter Single Phase 240V TO 3 Phase 415V Variable Speed Drive | eBay

    Well thats more like it.

    Way cheaper than Drives Direct by the look of it(though it was a quick look). I had heard of Chinese 240 to 415V VSDs... from Joe maybe? but I'd not seen one for sale before now.

    Stuart
    By sheer coincidence I happened to look for 415v output VFD's last night and put that one in my watch list. I am thinking if I can get one big enough it would be better for my lathe. The existing one will work well on the shaper, driving the huge 3hp delta connected motor I took off the Nuttall lathe. The shaper had a 1hp motor originally, according to Harty.

    Dean

  4. #18
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    Quote Originally Posted by Oldneweng View Post
    By sheer coincidence I happened to look for 415v output VFD's last night and put that one in my watch list. I am thinking if I can get one big enough it would be better for my lathe. The existing one will work well on the shaper, driving the huge 3hp delta connected motor I took off the Nuttall lathe. The shaper had a 1hp motor originally, according to Harty.

    Dean
    Hi Dean.
    coincidence indeed
    may be we should ask the seller for group buy discount
    i await for his answer about the 2.2kw unit . hope he have them available .

    cheers
    Peter

  5. #19
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    I believe these lathes came standard with a 3hp 3 ph motor , a lot of grunt for such a small lathe .

    Maybe a 2hp single phase replacement motor would suffice for amateur use . But may be a pain fitting it inside the base as new mounts would be required ?

  6. #20
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    Quote Originally Posted by morrisman View Post
    I believe these lathes came standard with a 3hp 3 ph motor , a lot of grunt for such a small lathe .

    Maybe a 2hp single phase replacement motor would suffice for amateur use . But may be a pain fitting it inside the base as new mounts would be required ?
    yeah . i was thinking of replace the motor with a single phase one which is easy to find but fitting it in there is a real pain for sure , hence the VFD option.
    Cheers
    Peter

  7. #21
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    Quote Originally Posted by thorens View Post
    Hi Dean.
    coincidence indeed
    may be we should ask the seller for group buy discount
    i await for his answer about the 2.2kw unit . hope he have them available .
    chrs
    Peter
    I already have a 4kw unit driving the lathe. I am looking for a bigger one. My search was more a matter of "watch this space". I am interested in how you go with the 2.2kw unit.

    I guess that the 220v output VFD's are aimed at the US market. It would be obvious that 440v output would be far more desirable in oz. The ol' economy of scale problem. What percentage of world population has access to 440v 3ph?

    Dean

  8. #22
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    Quote Originally Posted by thorens View Post
    yeah . i was thinking of replace the motor with a single phase one which is easy to find but fitting it in there is a real pain for sure , hence the VFD option. Cheers Peter
    I would *not* do this unless I had absolutely no other alternative. The machine was designed and is rigid enough to use all those HP, why would you want to handicap the machine capabilities if you could avoid it? If you do go this route, at least have the foresight to a possible future owner to hang onto the original motor etc. It cost the ex owner of a toolroom mill I bought $1000 for not doing that. He thought the machine was worth more money because it now had a 240V 3 phase motor driven by a single phase input VFD. My opinion was to the contrary and I paid less than he'd originally paid never mind his conversion costs. If he'd at least kept the original (2 speed 415V) motor I would have paid at least his original purchase price. PDW

  9. #23
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    Quote Originally Posted by PDW View Post
    I would *not* do this unless I had absolutely no other alternative. The machine was designed and is rigid enough to use all those HP, why would you want to handicap the machine capabilities if you could avoid it? If you do go this route, at least have the foresight to a possible future owner to hang onto the original motor etc. It cost the ex owner of a toolroom mill I bought $1000 for not doing that. He thought the machine was worth more money because it now had a 240V 3 phase motor driven by a single phase input VFD. My opinion was to the contrary and I paid less than he'd originally paid never mind his conversion costs. If he'd at least kept the original (2 speed 415V) motor I would have paid at least his original purchase price. PDW
    yes that is what I thought too . if the VFD 240v~415v 3 phase do 80% of what the real 415v 3 phase does then I'm more than happy .
    cheers
    Peter

  10. #24
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    Quote Originally Posted by Oldneweng View Post
    I am thinking if I can get one big enough it would be better for my lathe.
    But your problem is, if you get a 240v - 415V VSD, you cant supply the input current needed, which if I recall correctly is why I suggested 240V vsd in the first place.(unless things have changed or my memory is incorrect..... better than average chance lol))

    Stuart

  11. #25
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    Interesting reading here for chipmaster owners Chipmaster Variator assembly images
    Light red, the colour of choice for the discerning man.

  12. #26
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    Quote Originally Posted by Stustoys View Post
    But your problem is, if you get a 240v - 415V VSD, you cant supply the input current needed,
    These are a whole new field to learn. I am just getting my head around what I have. How much current do I need? I am in the long drawn out process of installing a 32A, 240v circuit to the shed. My current VFD tops out at 8A on the input for some reason. There is a big gap waiting to be filled there.


    Quote Originally Posted by Stustoys View Post
    which if I recall correctly is why I suggested 240V vsd in the first place.(unless things have changed or my memory is incorrect..... better than average chance lol))

    Stuart
    I don't know about that one. When was "the first time"? It is my understanding that I bought this lathe with the intention of using a 240v VFD.

    Can someone answer a question for me regarding the current carrying capability of 3ph v. 1ph cable. Given the same cross section, how much more current can 3ph carry.

    I just found this on the internut

    • 1 Phase Motor draws Current = 7Amp per HP.
    • 3 Phase Motor draws Current = 1.25Amp per HP
    That appears to be a serious improvement in efficiency. Is this kosher, and can it be applied to VFD applications.

    Dean

    Edit. I have found that 3ph cable can carry just under 3 times the capacity of the equivalent in single phase cable, but what I want to understand is how the almost triple capacity can be carried with 3 conductors compared to 2 conductors for single phase.

  13. #27
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    Peter,
    you are certainly obtaining a nice collection of machines there.

    Dean,
    Not only do you have more conductors, but as the voltage is higher you have less amps per HP/KW. Its the amps that cook the cable, not the watts.

    Ew
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  14. #28
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    Quote Originally Posted by Oldneweng View Post

    Can someone answer a question for me regarding the current carrying capability of 3ph v. 1ph cable. Given the same cross section, how much more current can 3ph carry.
    3 phase has three actives so each active carries it's share of the electricity...

    So if a single phase motor draws 15 amps, that means one wire has to carry the entire 15 amps current flow.

    If a similar sized three phase motor draw 15 amps, each wire is only carrying 5 amps..

    Of course volts also comes into it... higher the volts the smaller the cable thickness required...

    You look at the cable thickness of a car starter motor... 12V, might be a 3hp motor but need massive thick cables..
    Light red, the colour of choice for the discerning man.

  15. #29
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    Quote Originally Posted by .RC. View Post
    Interesting reading here for chipmaster owners Chipmaster Variator assembly images
    just printed that out , here at the library .....

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    Looks like a Dalek (Dr Who).
    Love the swarf control.

    Jordan

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