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3 Phase Convertors

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  • HAWK
    replied
    Originally posted by AV8OR
    Dear Hawk,

    If your question hasn't been answered check with the guys at Practical Machinist. Once you are there click on the link "Phase Converters and VFD".

    They are friendly guys and can answer your question.
    Great link!!!

    Leave a comment:


  • HAWK
    replied
    I appreciate everbody's replies. They are all informative and useful. I really appreciate your research and phone call Steved.

    Unfortunately this project is going to take a back seat until winter if not longer. Linkpin, I'll let you know what I end up doing.

    Again,

    Thanks to all!

    Leave a comment:


  • dcsound
    replied
    Another way to obtain three phase from single phase is to use a large single phase motor to drive a three phase generator. Have seen this done in many rural areas and it requires less wiring than building a phase convertor and supplies true (not derived) three phase.

    Leave a comment:


  • AV8OR
    replied
    Dear Hawk,

    If your question hasn't been answered check with the guys at Practical Machinist. Once you are there click on the link "Phase Converters and VFD".

    They are friendly guys and can answer your question.

    Leave a comment:


  • linkpin
    replied
    3 phase

    Here is another link for a 20hp converter from a different seller http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3830165535

    Joshua

    Leave a comment:


  • linkpin
    replied
    3 phase

    I too would like 3 phase I did some checking on ebay and there are a few people who sell converters here is a link to a 20hp. If you guys check it out let me know what you think and Hawk when you are up and running I would like to know what you ended up with and how well it works for you. http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3829019329

    Joshua

    Leave a comment:


  • HAWK
    replied
    Steve,

    I will probably take your suggestion as my electronic skills and knowledge are not only outdated, but somewhat rusty at best. The schematics of the 9 wire Y look quite simple and the CAP and HP calculations are not a problem. Thanks for your time.

    Leave a comment:


  • Steved
    replied
    Hawk:

    I have searched the net and have found out some things.

    In general the motor method will provide decent (+/- 10%) of line voltage on each phase and depending on your application this may be the way to go.

    Agreed that the SCR and microprocessor controlling would be better and would provide better voltage per phase but this method is quite electrically advanced and requires in depth knowledge of rectification and high power flyback circuits.

    In general the single phase AC would need to be rectified, turned into a decent DC voltage, and through switching and inductors, turned into a clean 3 phase system. I have a good idea what I am doing and this would take a LONG time to do it properly.

    I have found a web site that shows a really nice setup with lots of pictures and step by step instructions that could help you out. You would have to source out components capable of handling your higher power requirements.

    http://www.metalwebnews.com/howto/ph...converter.html

    I would advise that you stay away from the switching method as it would take up lots of time/money and would take away from your welding.

    Finally, to be legal (I have to), I am not endorsing the web page that I have submitted and these instructions are at your own risk. I have not reviewed the schematics in detail and I have not made a professional assesment of them.

    Now that is all out of the way, I am interested to see how things turn out.

    Let me know if you have any further questions.

    Regards,

    Steve

    Leave a comment:


  • HAWK
    replied
    Originally posted by Steved
    Hi Hawk:

    I will search and see what I can find out.

    In the end the SCR switching power supply will be more efficient but will be more difficult to build since there will be a PCB to lay out as well as the microcontroller code to write.

    I will do a quick search tomorrow to see what I can find.

    Regards,

    Steve
    Thanks.

    Leave a comment:


  • HAWK
    replied
    Steved,

    There will be 40 amp draw on 3 phase max at one time. One machine may be at idle while another starts and is running, but will only be running one machine at a time supplied from this 240VAC main.

    Leave a comment:


  • Steved
    replied
    Forgot to answer the question.

    I would guess that this system should work well for your shop assuming that it is small.

    This is a big guess since I really do not know how many things you are running at once but by the sounds of it you should be good.

    Leave a comment:


  • Steved
    replied
    Hi Hawk:

    I will search and see what I can find out.

    In the end the SCR switching power supply will be more efficient but will be more difficult to build since there will be a PCB to lay out as well as the microcontroller code to write.

    I will do a quick search tomorrow to see what I can find.

    Regards,

    Steve

    Leave a comment:


  • HAWK
    replied
    Steved,

    Do you have a schematic for a switching MP and SCR based phase convertor? From what I understand the rotary phase convertor should more than adequately supply the 3 phase power I need to run my shop equipment. Am I wrong?

    Leave a comment:


  • HAWK
    replied
    Steved ; klsm54 ; hankj,


    Thank you all for the valuable input. I think the motor is a good deal and being of the Y configuration should serve the purpose well.

    Leave a comment:


  • hankj
    replied
    Hawk,

    Hope this isn't too late. Go for the "wye" connected motor. For a converter idle motor, it doesn't make any difference as far as genertating the third phase, but there is an additional benefit in that there is a useable voltage available between any phase conductor and the "wye" cneter point. In transformers, that "wye" center point is grounded and represents transformer neutral.

    Here's a link to a schematic, if you need one: http://www.homemetalshopclub.org/pro...nv/phconv.html

    Be well.

    hank

    Leave a comment:

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