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Thread: VFD Questions

  1. #16
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    Interesting, which VFD did you buy exactly?
    Bumbling forward into the unknown.

  2. #17
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    A rpc wont melt a fractional motor just like your 200 amp sp service wont melt your 15amp cb in your panel. You don't turn them down. Its pull not push in electricity. You melt one its because you shorted a circuit.

    Also never put a circuit breaker device on the output side of a vfd between it and the motor. Vfd direct to motor on output. Read your manual.

    Your two machines your considering have zero need for vs so put in a 15hp rpc and panel in the shed or build one if you want to run 10hp loads.

    If you are only going vfd, I have teco 7500, fm50, ge fuji mini 300, hitachi xj200, wj200, bonfigilo (sp), and prob a few other drives all on machines that require or are handy with variable speed and most of them done under cnc code. All are great drives. Fm50 is the cheapest. With a large planer though thats a lot of mass to stop so i suggest a drive that can use dc braking with a large resistor or a purchased braking module. Hitachi Wj200 or teco 7500 will do that. The Hitachis are real nice and have great control station modules.

  3. #18
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    Thanks Mike! I’m dumping the idea of 10hp motors in my shop, so I’ve revisited that and plan to cap things off at 5hp~ which I’m fairly comfortable with having one already.
    Bumbling forward into the unknown.

  4. #19
    I have a Kay 10hp RPC that runs everything from a 3/4hp to a 10hp. It is rated to start 10hp at a time and run 30hp. it uses a 60amp 220v single phase circuit. Works for me.

  5. #20
    Quote Originally Posted by Mike Heidrick View Post
    ... never put a circuit breaker device on the output side of a vfd between it and the motor. Vfd direct to motor on output. Read your manual.
    ...
    Not that it applies here, but in case anyone is interested - -

    Its been a while, but I've worked on an industrial setup with a single, large VFD* (1500Hp, IIRC) operating something like 120 motors on a series of take-away conveyors. The motors ranged from 15Hp down to 2Hp(?) (again, IIRC). The VFD essentially powered a 'variable speed distribution bus' feeding all of the motors. So everything on the bus ran at the same speed. ...All 3-phase, but the concept would be the same if the VFD was supplied 1-phase.

    If any motor had shorted, the VFD could have melted the motor and the wiring. To prevent this, each motor had a suitably sized starter and overload between it and the VFD. (This interposing hardware also allowed them to shut-down a specific motor for service without affecting the rest of the line.)

    In another case, dough sheeting lines commonly use equipment with a single VFD multiplexed to 5 motors. Operator selects which one he connects to VFD, then runs it to make adjustments, stops it, and switches/connects to the next one. It uses common motor sizes, so VFD is size matched to the motor (and uses internal protections); interposing relays handle the VFD connection to respective motors.

    Not that I'd recommend this for Brian, or any home DIYer for that matter, but lots of things are possible when you throw away the manual.

    **************
    *VFD was about the size of a closet that would make SWMBO very happy!!!
    Last edited by Malcolm McLeod; 11-17-2017 at 7:33 PM.

  6. #21
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    Quote Originally Posted by Brian Holcombe View Post
    Thanks Mike! I’m dumping the idea of 10hp motors in my shop, so I’ve revisited that and plan to cap things off at 5hp~ which I’m fairly comfortable with having one already.

    I would not compromise on the machine because of this little point. I too am an electrical idiot, no offense, and am intimidated by things electrical.

    That being said, the difference between a 5hp mediocre planer and a nice planer like my SCM is night and day, and a lot less work as sizes are perfect with little to no tearout. Same can be said for jointers, shapers etc. There are few good single phase machines. I moved out of a shop with 3ph buss bars an all the walls to a small shop with no 3ph available, and so have had to deal with this.

    I run a 50 hp rotary converter for the main tools, and use VFD's on small stuff like the drill press and grinder. Nothing that you can not handle. A ready to go rpc big enough to handle what you want is around a grand.

    I bought the big rotary because I was going to move my wide belt to my new shop only to discover that the power lines coming to my shop were not big enough to handle the load, and $28K for the power company to upgrade, or I would have a smaller unit.

    One thing I would like to do is buy a Phase Perfect and get rid of the VFD's and RPC. I would have to buy a 20hp, but you could do what you want with a 10hp model. I kind of keep waiting for some competition in the market to bring the prices down, but has not happened. For about $3600 you could run anything up to 10hp, quietly, and leave the converter on all day. If you could swing it though, I would go with the 20hp, opens up a lot more possibilities and can be doubled to 40hp if the need should ever arise.

    That will be 2 cents.........

  7. #22
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    <p>
    This post is acting strangely, so I will try again.</p>
    Last edited by Brian Holcombe; 11-18-2017 at 9:56 AM.
    Bumbling forward into the unknown.

  8. #23
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    Thanks Larry for weighing in on this, I appreciate your opinions and experience. I&#39;m dealing with a one car garage for machines and a basement shop, which is my primary shop, dedicated in the majority to hand tools. So, while I originally wanted some pretty hefty pieces I&#39;ve had to back off to something more realistic and work around the space and capacity which I can manage at the moment.
    So gearing up for more capacity makes sense, but in my case the capacity is limited by my physical footprint. I can&#39;t really tighting things up and fit in 2-3 more machines like many of you might be able to do in your shops. I&#39;ve decided where the mortiser will go in the workshop (it&#39;s an easy decision in a one car garage) and that leaves me with enough space for either a jointer or a planer....so yesterday I bought a J/P from Minimax to account for both needs it was available in single phase. That now diminishes my need for excess three phase power and I&#39;m down to accounting for one machine, the 3hp Mortiser.
    Bumbling forward into the unknown.

  9. #24
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    Brian, from that message it looks like you might be getting the dreaded wonky character formatting. Perhaps this would help?
    http://www.sawmillcreek.org/showthre...98#post2745498

    JKJ

  10. #25
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    Thank you!
    Bumbling forward into the unknown.

  11. #26
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    Quote Originally Posted by Brian Holcombe View Post
    Thank you!
    Did it work? I'm keeping score.

  12. #27
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    A big rpc requires the correct service to feed it too. What size wire and service are you feeding a 50hp rpc with?

  13. #28
    Brian, I have run my 3hp slot mortiser off a static phase converter for 25 years with no problem. It has plenty of power for what it does, and that is the cheapest way out. If I were to set it up today, though, I would put it on a vfd to allow for boring at slower rpm's.

  14. #29
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    Thanks Kevin! After going round and round I think your recommendation and the others are right on. A VFD seems a sensible choice.

    John, I made no change but it seemed to clear up on its own.
    Bumbling forward into the unknown.

  15. #30
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    Quote Originally Posted by Brian Holcombe View Post
    John, I made no change but it seemed to clear up on its own.
    The HTTPS on my browser occasionally comes and goes for no reason I can explain. Maybe something to check if the formatting problem happens again.

    JKJ

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