4 prong to 3 prong, but 4 prong looks different?

Discussion in 'General Electronics Chat' started by fiveseven15, Nov 23, 2015.

  1. fiveseven15

    Thread Starter New Member

    Nov 23, 2015
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    hello, i am a bit stuck. i have a sewing machine that runs on/needs 220v (it actually can change from 200/220/240) but it has a 4 prong plug that isnt like the 4 prong plugs i usually see. its a round, twist-lock looking plug. i would like to wire it to the 220v in my garage which is a 3 prong.

    also, it says its a 3 phase, but from what i've read, residential power isn't 3 phase. so am i stuck and not able to use this? or is there possibly some adapter/transformer i could use? or could i just wire a 3 prong plug to the machine and use it that way. i was *about* to just wire the 3 prong cord i had laying around to it, but noticed the 4 prong looked different than what i have seen before, so i got a bad feeling and wanted to ask before i kill myself/burn my house down/destroy the machine. below is the plug on the machine, the plug i have to work with, and the label on the machine itself
    09ed363d-b3ce-4ac6-8f2b-94210d4d8ba8.jpg d0ee698b-87a6-4046-b2c6-e0c677896f2a.jpg 67697141-5ec2-43ff-8f69-7290e237f3e7.jpg
     
  2. tcmtech

    Well-Known Member

    Nov 4, 2013
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    Your machine is rated for three phase input so unless the VFD unit on it can handle being fed from a single phase source you are out of luck unless you want to make a dedicated phase converter unit to power it form your single phase power.
     
  3. fiveseven15

    Thread Starter New Member

    Nov 23, 2015
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    i think i'd end up screwing that up, does someone make one pre-built by chance?
     
  4. fiveseven15

    Thread Starter New Member

    Nov 23, 2015
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  5. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    The linked unit is rated for 1-3HP. Your motor is only about 0.5HP. I'd suggest you contact Zoro to see if that would be a problem (unlikely, I would have thought).
     
  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    A VFD would be better than the static converter. These guy's usually have the best prices, and they will assist you in hooking it up. I've bought a few from them over the years and they are very helpful to pick the best one for your needs.

    http://dealerselectric.com/item.asp?cID=50&scID=182&PID=24442

    Zoro is a full line hardware seller and not very helpful in troubleshooting and things like that, I've bought things from them too.
     
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  7. gerty

    AAC Fanatic!

    Aug 30, 2007
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    Another thing you need to take care of, your 220 outlet is rated at 50 amps and your motor is 2 amps. You need to add some sort of lower current protection should your machine develop a problem you don't want to feed it 50 amps which would destroy the whole works.
     
  8. tcmtech

    Well-Known Member

    Nov 4, 2013
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    As a last resort you could just download the manual and read the section on how to change it input voltage and phase to match what you have. :rolleyes:

    http://dixiesewingmachine.tzo.com/MANUALS/JUKISERVICE1/SC-800 engineer manual (No.00) 29315207.pdf

    Looking at it it looks like you can just feed your 240 VAC power to two of the three power inputs and it should work on single phase.

    Page 55

    12. Block Diagram top left corner is the input wiring.

    Looking at the manual it might even have internal connections and settings for 120 VAC single phase input too.
     
    Last edited: Nov 24, 2015
  9. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
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    Might not be the exact manual. The non-B version says 100 V and 100 V 3 phase. Multi-voltage may be the -B version.

    100 V is common in Japan.
     
  10. fiveseven15

    Thread Starter New Member

    Nov 23, 2015
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    i already tried. i have an SC-800 EB. 200-240v 3 phase only. my other machine has an SC-910 control box and that one can take 100-240v single or 3 phase...

    the thing that confuses me is, some people have been telling me static converters only work when it starts up, then switches to 1 phase to keep the motor going, but since the thing is computerized, would that damage any of the electronics? or are those parts generally single phase and only the motor itself is three phase?

    would VFD be safe to use on something that frequently starts/stops, but at very low loads? 67697141-5ec2-43ff-8f69-7290e237f3e7.jpg
     
  11. fiveseven15

    Thread Starter New Member

    Nov 23, 2015
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    good to know. i have never in my life had to deal wit three phase until this machine. the link you gave is exactly what i would like to have, since im worried that a rotary would get clogged with lint pretty fast. what do you use with the VFD? low load/frequent start/stop would be okay? its a very low (im assuming) load servo motor if that matters, and electronics/motor together only take minimum 1.8 amps (if im reading the label right) im really hoping that the one you linked to will work for something like a sewing machine, because its at a price that doesnt sting lol

    also, thanks again everyone. i tried to google most of this info, but since i dont have much electrical experience, im not really understanding exactly what i need to make this work without destroying the machine/killing myself
     
    Last edited: Nov 25, 2015
  12. fiveseven15

    Thread Starter New Member

    Nov 23, 2015
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    whoops. posted a duplicate pic above. this is all this particular control box will take
     
  13. tcmtech

    Well-Known Member

    Nov 4, 2013
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    If it has to have a three phase input to work the easiest way to get it would be a rotary converter. Those static box type are junk and won't work with electronics that need a three phase power source and VFD units are designed to run induction motors and tend to not work on electronic loads either being their output is a high frequency pulse width modulated waveoutput.

    As for building your own rotary unit its really easy. I have built more than I can count ranging from 1/4 Hp up to something like 20 HP. Heres how. http://www.electro-tech-online.com/threads/3-phase-converter-schematic-miller-system.100563/

    For something as small as yours I would suggest using a 1/2 HP TEFC motor.
     
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