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  1. #1
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    Default Phase Converter Help

    Since I have been having troubles getting someone to follow through and connect 3ph. I saw this and wondered how suitable it would be to buy?


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  2. #2
    Join Date
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    Mate....I am on a rural block with a 240V supply only. Due to this Forum I got interested in Chain Saw Milling which meant I needed to have a Jointer and Thicknesser with 300mm capacities to convert my own raw timber. I wanted to go with old cast iron machines that would easily handle Hardwoods. I went with a Rotary Converter which I put together myself with a huge hand from another Forumite. The Converter probably cost me around the $1100 mark at the time. It has been up and running for 5 years or so and does its job admirably. The Thicky and Jointer have 3Hp motors and the Panel Saw I bought later has a 5.5Hp on the main blade with 1Hp on the scriber. The Converter is rated at 5Hp but handles the Panel Saw with no problems. My Converter has 3 Ph outlets but I only ever run one machine at a time.
    The necessary plans and "secret black boxes" were supplied by Eurotec based in NZ and easily found on Ebay.
    The rotary system uses a 5Hp 3Ph motor and a transformer to go from 240V to 415V and the black box allows 3Ph to be generated. I have found the system very reliable, the only hickups I have had was a couple of sticky switches.(they are of Chinese origin) so replacing them was no problem.
    BobL is a great proponent of VFD's and from reading his Posts it seems they may be an easier (and cheaper) way to get your 3Phase running in your shed
    Just do it!

    Kind regards Rod

  3. #3
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    Default Phase Converter Help

    I have converted some of the smaller items over via VFD, drill press and grinders.
    But my 32Ē bandsaw has an incorporated induction motor that isnít compatible. I also have the 12Ē jointer and a large metal lathe that vfds are very expensive in that motor size range. Also having some form of 3ph means I can plug in and use any future machines.

    I have a surface grinder project and an industrial grinder that weíre going to be changed over to 240v but this would save that problem (new motors).
    Ö..Live a Quiet Life & Work with your Hands

  4. #4
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    I'm not sure if that phase converter would happily run that saw motor, is it more than 7hp?

  5. #5
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    Bandsaw is 3hp.


    The Colchester lathe has either a 5hp or 7.5hp motor I donít currently have access to mine to check which option it has.

    The thicknesser I think is a 5 also it could be bigger.
    Ö..Live a Quiet Life & Work with your Hands

  6. #6
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    Default

    3kw = 4HP. So I guess it isnít big enough.


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  7. #7
    BobL is online now Member: Blue and white apron brigade
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    Quote Originally Posted by DSEL74 View Post
    I have converted some of the smaller items over via VFD, drill press and grinders.
    But my 32Ē bandsaw has an incorporated induction motor that isnít compatible. I also have the 12Ē jointer and a large metal lathe that vfds are very expensive in that motor size range. Also having some form of 3ph means I can plug in and use any future machines. .
    I assume that compatibility is because the motors are 415V ∆?

    Fr those that are compatible then a quality Powtran 5HP (004G1) full vector drive VFD direct from the factory is only US$160 , Delivery via DHL is US$40
    These HD VFDs come with a bunch of memories so once set up you could program and store in memory setups for multiple machines.
    Then simply connect and recall the necessary VFD settings for that machine.

  8. #8
    BobL is online now Member: Blue and white apron brigade
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    Quote Originally Posted by DSEL74 View Post
    Bandsaw is 3hp.
    That looks like a dedicated 415V ∆ unit.
    The Colchester lathe has either a 5hp or 7.5hp motor I donít currently have access to mine to check which option it has.
    A 7.5HP motor will still run on a 5HP VFD - the VFD will simply not deliver more than 5HP, and lets face it, how often will you need the extra ponies? Normally these are just needed for heavy cuts and there's a fix for that and its just take more lighter cuts.

  9. #9
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    Hi DSEL74,

    Keeping in mind that this unit will be able to take up to 22 or so amps from the mains, you may need a dedicated circuit to run this. Also you would need to check all the cable sizes back to the street mains to be sure they can all handle the load.

    As to rotary phase converters in general, I'm not a big fan. The phase angles are not 120 degrees apart and the phase voltages tend to change with changes in load. This generates additional heat in connected motors. Having said that many people have them, are happy with them and report no problems.

    Personally, I'd go with a stepup transformer and VFD, although I understand some newer VFDs are able to step the voltage up without the transformer and they would be an even better idea. I've gone as far as investigating 3 phase standalone solar and batteries. The going rate is frightening.

    Cheers

    The Beryl Bloke
    Equipment er.... Projects I own

    Lathes - Sherline 4410 CNC
    Mills - Deckel FP2LB, Hardinge TM-UM, Sherline 2000 CNC.

  10. #10
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    Hi Dale, I would follow BobL's advice. Just because a motor is 'capable' (i.e. labelled and rated) to produce an output of 7.5Hp or whatever, it doesn't mean it will need the equivalent electrical input supply ALL the time. In addition to taking lighter cuts you can always reduce the speed/increase the torque with gearing. Torque is what';s needed for big cuts. If you want to take those big cuts at higher speed, you will need the power to produce that torque at higher speeds.
    The HUGE disadvantage of phase converters in my humble opinion is the fixed frequency. if there are resonances or vibrations in the machine at 50HZ - made MUCH worse by unequal phase angles and voltages - you can;t do a thing about it. With a VFD, you just go up or down a few Hz to stop those resonances - problem gone.
    As to price, you will find a 5kW (7.5Hp) VFD for a lot less than a phase converter. 415V Delta motors are the only problem: however, you WILL need a suitably or bigger transformer 240V to 415V for the phase converter too. No way around that in either case. It is possibly cheaper to find a 415V Star motor to suit cheaper than a transformer though.... 2-speed motors are a no-go zone without transformer though

    Your 3Hp bandsaw motor is not problem. Plenty of those motors about in 415Star/240Delta. In fact I have one you can have for a negotiated fee

    PS: how is the hole broaching going?
    Cheers, Joe
    again completely retired - more time to contemplate projects and spend more shed time....

  11. #11
    Join Date
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    I've got a home-rolled rotary converter with 7.5HP idler and 5KVA 240-415 step up transformer. I haven't done an accurate tally of the costs but the transformer alone was about $700 so I'm guessing probably around $1200.
    My Takisawa lathe has a dual speed 5HP/3HP motor and it runs happily on the low speed (3HP) winding, but won't start it from standstill on the high speed setting (although I can get it spinning on low and then flick the motor switch on the lathe to high). I still need to get back to it and tweak the balance capacitors a bit which will likely help the high speed start.

    Its great having an easy to use 3-phase source available. I've got a 3ph power hacksaw that just plugged straight in, and my Van Norman mill which has separate spindle and feed motors did the same.

    In saying that, my converter is a physically large lump of gear and needs a decent power supply circuit (I've put in a 32A one). Starting larger motors on machines like a lathe with a lot of inertia definitely draws a lot of current through the converter.
    I understand that VFD's can be programmed to be a lot softer on start so something to consider if your supply is a bit shaky.

    I'm happy I built the converter, but if I was starting from scratch and just had simple machines with a single motor/winding and only being used one at a time I'd probably just go with one of the VFD's that BobL recommended and set up the multiple profiles.

    Steve

  12. #12
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    I use an older model 5hp phase converter, from Phase Change Converters, to power a 5hp Colchester lathe. It worked well at all speeds except the 2 highest speeds (1860 and 2500) where I had to slip the clutch a little to prevent tripping the circuit breaker. I picked up some second hand Allen Bradley VFD"s, 3 phase input 380 - 480 volt, and fitted one between the phase converter and the lathe motor. Starting problem disappeared and now I have infinitely variable speed.

  13. #13
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    It looks like a very nice unit DSEL74, it is no longer listed for sale, did you get it?

  14. #14
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    Quote Originally Posted by Techo1 View Post
    It looks like a very nice unit DSEL74, it is no longer listed for sale, did you get it?
    No I didnít. I wasnít confident it would suit.
    Ö..Live a Quiet Life & Work with your Hands

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