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  1. #1

    Too much voltage 246v from power company

    To anyone with advice,

    I've had 2 refrigeration compressors go bad because of too much voltage from panel to condensing unit. Currently 246v. I've solved the problem with a transformer but have this question for all you electricians.

    Why does the power company say "they are within their range" at 120v plus/minus 5% which puts each leg at 126v or 252v for 1phase? Compressors are 208/230 and can't handle that kind of constant power.

    Any thoughts are appreciated!

    Thx,
    Refrigeration nut

    Leroy driver

  2. #2
    Join Date
    Nov 2007
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    Texas
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    233
    246 is fine. I was told on 208/230-240 equipment 197-255 was acceptable. Heck the voltage at my house is 253 and I don't have any problems. Most problems occur from the voltage dropping too low. I'd be more worried if it was 197. Don't think 246 VAC is causing your problems

  3. #3
    Well, they don't make compressors like they did 20yrs ago! Lol built like tanks back in the day. Thanks for the response, I will continue to investigate.

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
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    14,915
    In my area, 246 to 252v is the norm.
    It falls within the maximum voltage specs of every compressor I've bothered to look at the specs for.
    It does give you a little extra capacity over the manufacturers rating.
    If more government is the answer, then it's a really stupid question.

  5. #5
    Join Date
    Dec 2008
    Location
    NW Iowa
    Posts
    128
    I would not think 246 volts is a problem. It's the norm around here.

  6. #6
    Nominal voltage in New Zealand is 230V but I have had problems with it going over 254V and equipment failing. The biggest problem however is that the voltage is no longer purely sinusodial due to the switched power supplies to computers, LED and halogen lights, washing machines using DC motors etc etc. If you put an osciloscope then you might well see that the voltage spikes are far higher than that your 246V indicates especially if your voltmeter is not a pure RMS meter. I suspect that it might have to do with insualtion breakdown of the windings. The earlier failing is the same as when you control the speed of a motor with a cheap speed controller, motors will hum and fail earlier.

    For computer equipment I use a UPS that first transforms the power and then generates a pure sinusoidial voltage. There are cheaper solutions that stabilise the voltage and transform it in a pure sinus without having a UPS built in. Unfortunately those are not much use if you have trouble with bad brown outs where the mains falls away to very low voltages where a UPS may be required instead. (I recently looked into those because my daughter has trouble with "brown outs" too low voltage when all the hot water cylinders are turned on through ripple control. The computer controlled radio and washing machine were going silly).

  7. #7
    Join Date
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    Quote Originally Posted by AmadeusMozart View Post
    Nominal voltage in New Zealand is 230V but I have had problems with it going over 254V and equipment failing. The biggest problem however is that the voltage is no longer purely sinusodial due to the switched power supplies to computers, LED and halogen lights, washing machines using DC motors etc etc. If you put an osciloscope then you might well see that the voltage spikes are far higher than that your 246V indicates especially if your voltmeter is not a pure RMS meter. I suspect that it might have to do with insualtion breakdown of the windings. The earlier failing is the same as when you control the speed of a motor with a cheap speed controller, motors will hum and fail earlier.

    For computer equipment I use a UPS that first transforms the power and then generates a pure sinusoidial voltage. There are cheaper solutions that stabilise the voltage and transform it in a pure sinus without having a UPS built in. Unfortunately those are not much use if you have trouble with bad brown outs where the mains falls away to very low voltages where a UPS may be required instead. (I recently looked into those because my daughter has trouble with "brown outs" too low voltage when all the hot water cylinders are turned on through ripple control. The computer controlled radio and washing machine were going silly).
    I would need to know more about power distribution practices in new Zealand to help you.v
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    2 Tim 3:16-17

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  8. #8
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    Quote Originally Posted by LeroyDriver View Post
    Well, they don't make compressors like they did 20yrs ago! Lol built like tanks back in the day. Thanks for the response, I will continue to investigate.
    How long has each compressor lasted?

    246 is fine.
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  9. #9
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    Quote Originally Posted by beenthere View Post
    How long has each compressor lasted?

    246 is fine.
    Agreed, time to start looking for a system problem......

  10. #10
    Join Date
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    Higher voltage within specs on nameplate equal lower amps, which would be better for compressor and electric bill usually lower voltage is what would cause you problems.
    If it aint broke don't fix it!!!

  11. #11
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    Quote Originally Posted by brettrobbins View Post
    Higher voltage within specs on nameplate equal lower amps, which would be better for compressor and electric bill usually lower voltage is what would cause you problems.

    219 volts at 18.26 amps is 4000 watts, 246 volts at 16.26 amps is 4000 watts. So no savings because of the higher voltage and lower amp draw.
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  12. #12
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    I remember reading that something like 50 % of all field compressors fail. Due tobad install practices. Maybe that is the problem

    On the electric side unless you are getting some really high voltages like 140 on what is suspose to be 125 u will be fine. Like others have said.

    Dang old post op probably will not return to this site

  13. #13
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    Quote Originally Posted by LeroyDriver View Post
    To anyone with advice,

    I've had 2 refrigeration compressors go bad because of too much voltage from panel to condensing unit. Currently 246v. I've solved the problem with a transformer but have this question for all you electricians.

    Why does the power company say "they are within their range" at 120v plus/minus 5% which puts each leg at 126v or 252v for 1phase? Compressors are 208/230 and can't handle that kind of constant power.

    Any thoughts are appreciated!

    Thx,
    Refrigeration nut

    Leroy driver
    There is one standard for the power company, and then there is the voltage standard acceptable to equipment manufacturers. They may be different. Let's start at the beginning.

    IF the compressor is actually rated with the 208/230 volt rating (the "slash rating") then you are fine at that 246 voltage. Being 16 volts above 230 should be withing manufacturer's specs. You can ask them to be certain. I would ask.

    HOWEVER, if you are using equipment that is rated "208" on the label, you are above the intended voltage rating and in fact are in violation of the NEC.

    Does that help?
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    2 Tim 3:16-17

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