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Technical Phase converters, one big rotary converter or repower the equipment ?

Discussion in 'The Hokey Ass Message Board' started by 31Vicky with a hemi, Nov 21, 2018.

  1. Moriarity
    Joined: Apr 11, 2001
    Posts: 30,773

    Moriarity
    SUPER MODERATOR
    Staff Member

    I have an old Bridgeport milling machine and is a rotary converter by Anderson converters. My mill is 1 hp and the converter is rated 5 hp and has a 5 hp motor on it. I bought the box separate and added the motor myself. Three phase motors are cheap used and pretty easy to find. I can’t remember how much the box was but it was affordable. I took a pic of the box with their phone number on it[​IMG][​IMG][​IMG]


    Sent from my iPhone using The H.A.M.B. mobile app
     
  2. PackardV8
    Joined: Jun 7, 2007
    Posts: 1,170

    PackardV8
    Member

    FWIW, large 3-phase air compressors do not play well with static, rotary or VFD converters. The continuous starting under load will kill the motor or the converter sooner or later.

    jack vines
     
  3. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,132

    DDDenny
    Member
    from oregon

    Mark
    I usually don't use the OMG lingo, but OMG, a pinstriped Bridgeport with a gold metalflake steering wheel.
    I now see why you have never cooked in your kitchen!
     
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  4. Moriarity
    Joined: Apr 11, 2001
    Posts: 30,773

    Moriarity
    SUPER MODERATOR
    Staff Member



    Haha, when I got that machine it was a really awful tan color. I made the mistake of stripping the paint with aircraft paint remover. it removed the paint and some really thick clay like primer. what it left was the entire surface was a rough casting. I mudded and primed the whole thing, and painted it candy wild cherry over a gold metalflake base
     
  5. BJR
    Joined: Mar 11, 2005
    Posts: 9,814

    BJR
    Member

    Who else has ceramic tile walls in their shop? Other then Mark? Stand up and be counted!:p
     
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  6. Another choice is a 3 phase generator.
    I have a 2 cly onan from a motor home built in the 70s it runs 3 phase up to 50 amp. 60amp start. Burns 1-1 1/2 gallon an he
     
  7. I bought a Hitachi VFD for my Bridgeport, wired it up in an afternoon and it works perfectly. It was $110 on Ebay. Good luck!

    Sent from my SM-G950U using The H.A.M.B. mobile app
     
  8. Fellas this guy has ALL of the cool stuff.
    There's nothing left for anybody else.
     
    Last edited: Nov 22, 2018
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  9. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 3,375

    GearheadsQCE
    Alliance Vendor

    Now I gotta paint my mill to keep up with the cool guys. I want purple flake, but all I have is apricot.
     
  10. metlmunchr
    Joined: Jan 16, 2010
    Posts: 861

    metlmunchr
    Member

    What is the horsepower of the compressor?

    A compressor is the most difficult machine to start using a rotary converter due to both the inertia of the flywheel and the fact that its also pumping as it comes up to speed. Normal recommendation for a rotary if used with a compressor is at least twice the compressor hp and 3x the compressor hp is even better. So a 5hp compressor needs either a 10 hp or a 15 hp rotary. Downside to large rotaries is the amount of power they use in standby when no machines are running. Something sitting around continuously eating 3 or 4 kW for 8 or 10 hrs a day can add up to a good chunk of money in the course of a month. The manufacturers of rotaries like to talk about efficiency while running rather than in standby, but for the most part in a small shop the bulk of the time it would be idling in standby unless you want to start it every time you need to run a machine.

    A vfd can start a compressor just fine assuming its properly sized. Most VFDs are spec'd based on 3 phase input, so if you go to single phase input you have to size the drive at 1.5 times the hp of the compressor motor to avoid overloading the VFD. Additionally, you have to program the ramp rate to allow for the flywheel inertia and the fact that the compressor is loaded as it comes up to speed.

    Not sure what you mean by "reciprocating machine". Is that like a power hammer or Pullmax or similar machine with a substantial flywheel or something like a large power hack saw where there's no flywheel?

    Single phase motors have become ridiculously expensive, particularly if you need 1725 rpm ones. For example, a 5hp 3450 rpm will run around $225 to $250 for a good quality motor while a 5hp 1725rpm will go for $400 to $550. 7.5hp is in the $1000 neighborhood and a 10hp is around $1400.

    $6K for a 3 phase service might be okay if you own the building, but not so much if you're renting.

    My choice if renting, which hasn't been mentioned so far, would be a Phase Perfect. A 10hp PP is about $3200 and a 20hp is about $5200. A PP doesn't have to be oversized for starting purposes as the rating is based on both starting and running motors at the full rating numbers. The power use in standby mode is about 100 watts for the 10hp and 200 watts for the 20hp. Operating efficiency is 95% to 97%. Multiple motors can be run simultaneously up to the full rating of the PP. http://www.phasetechnologies.com/products/phase-perfect-240v/overview

    Static converters are a non-starter for any 3 phase motor that's sized to run anywhere near full load. A buddy of mine started a business in his single car garage several years ago with a horizontal band saw and an iron worker, both 3 phase, sawing, punching, and bending flat bar for one customer. Bought static converters for both machines, and burned up $1500 worth of motors in 6 months. Made it thru that, and has a 48,000 sq ft shop today, but it was sure tough to spend that kind of unexpected money when he was barely bringing in enough money to keep the lights on and put food on the table.
     
  11. 64-classic660
    Joined: Nov 16, 2018
    Posts: 44

    64-classic660

  12. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 10,244

    theHIGHLANDER
    ALLIANCE MEMBER

    This what I bought for my 10HP compressor...

    https://www.grainger.com/product/DAYTON-10-HP-High-Torque-Farm-Duty-6K970

    I'm shocked it's now twice what retail was in 2005, maybe I shouldn't be (?), but still. I simply asked for a discount and got it as I shared in the 1st reply. At the time I figured it was the best choice and it was the only 3PH thing I had. At $640-something andhaving only $750 in the compressor to start with the whole investment was cake. A new vertical 5HP with reasonable CFM ratings was $1,800. I could sell my get up for maybe $1,800-2,000 but I'm a bit of a compressor "snob" anyways. Since it ran for so little time even the electrical use was less in the long run. So today I have 1 of each motor should needs change. I get it that there's more in the asking for your needs but it pays to shop. I now have our old 5HP Kellogg in the home shop and the big one in the restoration shop. It pays to dig around, ask for discounts on new stuff, even shop at the industrial service places. Someone's abandoned motor might be on the shelf collecting dust. My whole shop electric bill is usually $90-120. I don'thave a dozen employees and machines running all day, and I turn shit off that I'm not using. I worry more about the gas bill now that we have to pay for "everyone". Insert your own politics there, I don't want Ryan to put me in "detention" for it :eek:

    Good luck,but let us know what you do. In the meantime I'll try to do some local shopping for ya. Cleveland isn't that far from Motown (that's still where you are, right?). PM me a list of motors you might want/need. Still some mom n pop motor shops around here n Toledo.
     
  13. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,132

    DDDenny
    Member
    from oregon

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