Page 1 of 2 12 LastLast
Results 1 to 15 of 20

Thread: Static Phase Converters - Anybody use them?

  1. #1
    Join Date
    Feb 2003
    Location
    Conway, Arkansas
    Posts
    12,780

    Static Phase Converters - Anybody use them?

    I am finding way too many good deals of old 3 phase power tools for crazy cheap prices at times. What's the trick to using a static phase converter with power tools? I've looked at rotary but boy are they pricey!

    Inquiring minds want to know.
    Thanks & Happy Wood Chips,
    Dennis -
    Get the Benefits of Being an SMC Contributor..!
    ....DEBT is nothing more than yesterday's spending taken from tomorrow's income.

  2. #2
    These days, good VFD's are so cheap, there's very little reason to consider a rotary converter, let alone a static one.

    For under $300 you can get a 3HP, tried & true TECO. It gives you vari-speed, soft-start, dynamic braking, overload protection, and re-start protection. (In other words, you don't need a mag starter.)

    The only difference is, you ideally want one VFD for each motor.
    Last edited by Allan Speers; 06-14-2019 at 1:47 AM.

  3. #3
    Join Date
    Feb 2003
    Location
    In the foothills of the Sandia Mountains
    Posts
    15,105
    I have been running my lathe & mill off a single Phase-O-Matic static converter since the mid 90's without any problems. I would have gone with a VFD but I don't think they were around at the time.
    Please help support the Creek.

    When everything is coming your way, you're in the wrong lane.

    - Steven Wright

  4. #4
    Join Date
    Dec 2010
    Location
    WNY
    Posts
    6,193
    VFD's are a good choice up to 3 HP motors. Above that, though, they go up in price dramatically, at least from what I saw when I was looking for one that could handle 5 HP. So we ended up using a static phase converter on it and the owner has had no problems in 2+ years. You will lose 1/3 of the power, so if that's important don't use one. In our case it was going on a jointer and 3+ HP is still plenty. The static phase converter was custom built by a local company (Sanborn, NY), and cost just over $100. The only downside with SPC's is they are not meant to be cycled very often; max. 10 on/off cycles per hour to avoid premature failure.

    John

  5. #5
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
    Posts
    5,349
    Quote Originally Posted by Allan Speers View Post
    For under $300 you can get a 3HP, tried & true TECO.
    I think you mean under $200 for the FM50-203-c.

    For my stationary machines that are three phase iíve got a VFD/machine, such as TS, jointer, bandsaw, and planer (whenever I get around to restoring it).
    For the other few 3 phase machines (spindle sander, grinder/buffer, and soon to be disc sander, Iíve got a 2hp VFD ďsub-stationĒ setup. Since these machines are used less frequently, I plug and unplug both the switch and power for each machine as needed. Settings are shared between the machines as far as accel/decel times.

  6. #6
    Quote Originally Posted by Matt Day View Post
    I think you mean under $200 for the FM50-203-c.

    Wow, they've really dropped in the last few years!

    Well, there you go.

  7. #7
    Join Date
    Feb 2003
    Location
    Conway, Arkansas
    Posts
    12,780
    So, I'd need to get a VFD for a 3 HP motor and that VFD would operate my 3 HP 3PH motor on a TS for example...without any other hardware? Sorry, but I'm just now researching this stuff and having to learn as I go.
    Thanks & Happy Wood Chips,
    Dennis -
    Get the Benefits of Being an SMC Contributor..!
    ....DEBT is nothing more than yesterday's spending taken from tomorrow's income.

  8. #8
    Join Date
    Nov 2007
    Location
    Buck Lake, Alberta
    Posts
    169
    One thing I haven’t seen mentioned yet. The cheaper VFDs that everyone so far is talking about will run a 240 volt 3 phase motor. When you get into different 3 phase voltages the cost goes way up. A lot of the 480-460 volt motors can all so be wired to run on 240-220 volt power, but some don’t.

  9. #9
    Join Date
    Aug 2013
    Location
    Princeton, NJ
    Posts
    6,174
    Blog Entries
    7
    Quote Originally Posted by Allan Speers View Post
    These days, good VFD's are so cheap, there's very little reason to consider a rotary converter, let alone a static one.

    For under $300 you can get a 3HP, tried & true TECO. It gives you vari-speed, soft-start, dynamic braking, overload protection, and re-start protection. (In other words, you don't need a mag starter.)

    The only difference is, you ideally want one VFD for each motor.
    I have three machines which run on one rotary, one of which has a dust collector which is also 3ph running at the same time, it's now a considerable cost savings to individual VFD's.

    Rotary also offers the advantage of not needing to control the machine any differently than you would otherwise, with machines that are on and off a lot, this is handy. I run a milling machine with a VFD and winding it up and winding it down at the start and stop of every cut is a PITA when you're doing certain tasks. If I ran my slot mortiser that way it would drive me nuts, same with the Maka. I have no idea how a Maka would run with a VFD.

    So, don't be so quick to write off the rotary.
    Bumbling forward into the unknown.

  10. #10
    Join Date
    Aug 2015
    Location
    N. Texas
    Posts
    1,358
    Quote Originally Posted by Dennis Peacock View Post
    So, I'd need to get a VFD for a 3 HP motor and that VFD would operate my 3 HP 3PH motor on a TS for example...without any other hardware? Sorry, but I'm just now researching this stuff and having to learn as I go.
    Make sure the manufacturer specifically states it will handle your specific conditions; in this ^^case^^ 3 HP with 230V/1ph input. Or you should de-rate the VFD you purchase.

    The one thing that seems to throw most folks is 'de-rating' a 3ph VFD to use 1ph input power - -
    - 3HP/230V/1ph motor typically pulls around 17 FLAmps.
    - 3HP/230V/3ph motor typically pulls around 10 FLAmps.

    If you want to power a 3HP/3ph motor, the output of the VFD must be sized to deliver 10 Amps. However in typical residential use, the input side of the VFD has to 'make' this 3HP from a 1ph supply, which requires 17 Amps. So, the VFD sees 17 Amps input and 10 Amps output - both equaling 3HP - and just like wire, it must be sized for this amperage.

    Many manufacturers have begun advertising their VFDs to handle a particular HP WITH 1ph input/3ph output, but if they don't, then prudence dictates you de-rate the VFD.

    In the above case you'd need a 5HP VFD to power a 3HP motor, since a 5HP/3ph VFD can handle 15-16 FLAmps at its input terminals (17A is just a tiny O'Load, and probably well within the safety margins of the manufacturer). So, you have 'de-rated' a 5HP VFD to 3HP.

    I hope my explanation is clear and concept may seem confusing, but don't get lost in the details.
    Last edited by Malcolm McLeod; 06-14-2019 at 10:34 AM. Reason: Clarity + I assumed you have 230-240V ... I hope
    Molann an obair an saor.

  11. #11
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    50,222
    Dennis, relative to rotary, if I'm not mistaken, you can reduce the cost by building your own since getting a functional, big and older three phase motor to do the work can be pretty inexpensive. There are articles "out there" that say how to do this. They are probably just fine for common tools, but not recommended for machines like CNC because the more crude DIY rotaries do not provide balanced power output on all the phases.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  12. #12
    Join Date
    May 2008
    Location
    MA
    Posts
    1,758
    I ran a 10hp widebelt sander off a phase-o-matic static converter for years. I know it means less than max HP, but it turns out I didnt need max hp and it worked perfectly fine. The converter I picked up used (10 to 15hp range I believe it is rated for), for $150. Hard to beat for 10hp (even if only 6.66hp)

    A couple years back I was able to get a 10hp rotary PC for $500 (again used). This I acquired at the same time as a new/different widebelt. So now I use that.

    But to be honest, there was no difference in performance for me. (static vs rotary).

    I tried selling the static converter a couple times but no interest, should put it up for sale again. I toyed with the idea of getting a used 3 phase motor (they are cheap on CL) and coupling with the static converter - making it a rotary converter. Figured that would give about a 10hp RPC with less than $300 in it. But I got a different one now so dont want another project. Someday. Maybe.

    A lot of positive experiences with VFD and not much love for the static converters by the purists. But my experience was 100% positive and no need to over think it, the static converter worked fine even at the larger HP. VFD gets $$ as you increase HP.

  13. #13
    Join Date
    Sep 2009
    Location
    Medina Ohio
    Posts
    3,824
    Way back when phase converters were not supposed to exit we got one from an electric motor place we got a static converter for one motor but later added a floating motor to run several different motors.

  14. #14
    Ten years ago, I built a rotary phase converter for neighbor for his machine shop. Used a salvaged three phase motor, coupled to a Herbish dryer motor. The Herbish dryer motor has a lead that line voltage appears upon when it reaches operational speed. Household dryer motors have the same feature. It prevents the heating element from running if fan isn't turning. The line voltage allowed for a relay to pull in and excite the three phase motor. Put a magnetic starter of whole shebang, so if power went out, and then returned, system wouldn't self destruct by letting "magic smoke" out. Web site "Practical Machinest" has many different shop made RPC's on it. With a RPC, you have two choices to get it running, either a pony motor, or relay and capacitors.
    Last edited by Bruce Wrenn; 06-14-2019 at 9:37 PM.

  15. #15
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
    Posts
    5,349
    Malcolm,
    I thought derating the vfd was only needed at above above 5hp? And also isnít it really all about amps? How many amps the vfd can output (10.5A for the FM50 IIRC) and the motor tag on the machineís motor tag.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •