Using a 1 VFD as 50Hz->60Hz converter for window A/C unit

Discussion in 'General Electronics Chat' started by damiannz, Apr 20, 2014.

  1. damiannz

    Thread Starter New Member

    Apr 1, 2010
    5
    0
    Hi all, I saw this on an old thread:
    This is pretty much what I'm trying to do. I have a cheap 500W 115V 60Hz window air conditioner (Frigidaire FRA054XT7), which is wired with the fan+compressor running off the same run cap, no start cap: [​IMG]

    The compressor is 115V 60Hz with 4.5A running current, and according to the nameplate, 26A locked rotor current. Domestic supply here is 240V 50Hz. In vain I tried to power this via a 12VDC car-style 800W inverter but, as expected, the inverter cut out when the compressor kicked in.

    So I'm considering powering this unit via a single-phase VFD. I'm looking at the Invertek Optidrive ODE-2-22110-1KB42-01 (10.5A rated) or ODE-2-12075-1KB12-01 (7A rated) (http://www.invertekdrives.com/varia.../model-data/datasheet.aspx?mID=ODE-2-12075-1K), both are 185% current rated for 2s. I would consider rewiring the AC so that the compressor and fan are always on in order to make use of the soft-start capabilities of the VFD, but I'm not sure that this will actually work.

    Can anyone advise? Will this work, or be even vaguely efficient?
     
  2. crutschow

    Expert

    Mar 14, 2008
    12,991
    3,226
    Wouldn't the cost of the drive be comparable to the cost of a new air conditioner with the correct voltage and frequency rating?
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    ...Or replace the motors with a 240v versions.
    Max.
     
  4. damiannz

    Thread Starter New Member

    Apr 1, 2010
    5
    0
    Yes. Call me stubborn, I want to see if I can do it this way. :) The AC unit has a number of nice features -- mainly, it's very small, low powered, and very light. There's nothing comparable size/weight/power usage available at 240V 50Hz.
     
  5. damiannz

    Thread Starter New Member

    Apr 1, 2010
    5
    0
    I think that would involve flushing the coolant out of the compressor, which is beyond my abilities..
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Obtain a 240v to 120v construction site transformer and hook that up.
    Max.
     
  7. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    Still the wrong frequency.
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,509
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    Some motors there is not that much difference in performance, obviously run slower on 50hz, I imagine a 2 pole motor for a compressor?
    Max.
     
  9. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    Only if the label says so, and I have never seen a compressor rated for 2 frequencies.
    (I probably live a very sheltered life here in the U.S.A.)
    Even if the iron doesn't saturate magnetically and overheat, that 16% change in speed comes right off the cooling capacity (it's linear).
    From my point of view, it's a very risky, "maybe".
     
  10. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    A 60Hz motor run on 50Hz is almost certain to run overcurrent and overheat very quickly.

    A 500W window mount airconditioner is very cheap these days, probably a similar price to a VFD large enough to handle the start current.
     
  11. oldgoaly

    New Member

    Apr 6, 2014
    8
    3
    Check the compressor motor plate many compressors a 50/60 hz, saves in their UL testing here in the states.
     
    THE_RB and MaxHeadRoom like this.
  12. YolandaStanley

    New Member

    Dec 18, 2014
    1
    0
    Hi.
    I recently purchased a used window air conditioner for hot summer days. On the other hand, I'm a bit confused about the exhaust tube and it how it functions concerning the windows.
     
  13. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Well yolanda apparently what you need is a VFD to solve your exhaust tube problems. Personally I don't let my drain tube anywhere near windows, as I had a bad experience as a kid, and also I'm not an exhibitionist.
     
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