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  1. #1
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    Jun 2010
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    06E Compressor issue

    Just looking for something else to check......
    I have an 06E compressor 230v part winding start that was recently replaced (last week?). Apparently when it was installed and started up in ran/sounded fine. As of 3 days ago the customer reported a noise. Went to check the compressor and found that the noise happens on start up. When the first contactor pulls in the compressor hums. The second contactor pulls in and off she goes, runs fine. The sound they are complaining about is the loud hum. This system pumps down at shut down, so when the solenoids open the pressure creeps up to start the compressor. Not a lot of load. Two of the three heads have unloaders. Tried unloading both heads before starting, same result. The voltage is 238-240 across the 3 lines. The 1st contactor is wired to terminals 1-2-3, the second is wired to 7-8-9. Terminals 4-5-6 are jumped with a bar. Both contactors are new with the compressor.

    So, what Im looking for is a reason that the compressor wont start turning with the 1st winding. Again, once the 2nd kicks in it runs fine, so I know its not seized. The power leads are the same on both contactors, so its not a rotation thing, plus if it was, the issue would pop up when the 2nd kicked in. Checked the ohms of the windings, 1st is .9 ohms across 1-2-3, 2nd is .4 ohms across 7-8-9. The lag for the second contactor is controlled by the compressor timer which states 1sec +/-.5 sec. Which it is operating at.

    It appears electrically sound. Since it runs once at 100%, seems mechanically fine.

    For a little background, the compressor was replaced due to a broken piston. This an older split system. The previous company had done some work out in the system on leaks. When the new compressor was installed and started, a lot of oil returned back and needed to be removed. It appears that the previous company kept adding oil (4 empty gallon containers onsite). Looks like once they fixed the issue out in the system the oil came back and filled the compressor. The cylinders were full of oil upon original diagnosis.

    Again, the issue I am trying to solve is the loud hum when just the 1st winding is engaged. I look forward to any suggestions.

    Thanks




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  2. #2
    Join Date
    Jul 2007
    Location
    The Hot South
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    What’s the amp draw on all 6 leads?
    The 2nd most important amendment is to protect the 1st....

    Free Air Conditioner Sizing Chart

  3. #3
    Join Date
    Sep 2002
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    Timing too long between windings would be my first guess. Should be like a second or two - how long is this poor guy humming so that they "hear" it??? <g>

    What happens if you bring both contactors in together? I would prefer just running it that way anyway. Much better for the motor.

    PHM
    --------


    em both on
    Quote Originally Posted by Surfintech72 View Post
    Just looking for something else to check......
    I have an 06E compressor 230v part winding start that was recently replaced (last week?). Apparently when it was installed and started up in ran/sounded fine. As of 3 days ago the customer reported a noise. Went to check the compressor and found that the noise happens on start up. When the first contactor pulls in the compressor hums. The second contactor pulls in and off she goes, runs fine. The sound they are complaining about is the loud hum. This system pumps down at shut down, so when the solenoids open the pressure creeps up to start the compressor. Not a lot of load. Two of the three heads have unloaders. Tried unloading both heads before starting, same result. The voltage is 238-240 across the 3 lines. The 1st contactor is wired to terminals 1-2-3, the second is wired to 7-8-9. Terminals 4-5-6 are jumped with a bar. Both contactors are new with the compressor.

    So, what Im looking for is a reason that the compressor wont start turning with the 1st winding. Again, once the 2nd kicks in it runs fine, so I know its not seized. The power leads are the same on both contactors, so its not a rotation thing, plus if it was, the issue would pop up when the 2nd kicked in. Checked the ohms of the windings, 1st is .9 ohms across 1-2-3, 2nd is .4 ohms across 7-8-9. The lag for the second contactor is controlled by the compressor timer which states 1sec +/-.5 sec. Which it is operating at.

    It appears electrically sound. Since it runs once at 100%, seems mechanically fine.

    For a little background, the compressor was replaced due to a broken piston. This an older split system. The previous company had done some work out in the system on leaks. When the new compressor was installed and started, a lot of oil returned back and needed to be removed. It appears that the previous company kept adding oil (4 empty gallon containers onsite). Looks like once they fixed the issue out in the system the oil came back and filled the compressor. The cylinders were full of oil upon original diagnosis.

    Again, the issue I am trying to solve is the loud hum when just the 1st winding is engaged. I look forward to any suggestions.

    Thanks




    Sent from my iPhone using Tapatalk
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  4. #4
    Join Date
    Sep 2002
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    Sorry; I missed the "one second timing" the first time I read your post.

    Still: I'd remove the timer and bring it on across the line. Part winding start causes more problems that it solves - I've always considered it as pretty much a sales-gimmick.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  5. #5
    Join Date
    Jul 2007
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    Quote Originally Posted by Poodle Head Mikey View Post
    Sorry; I missed the "one second timing" the first time I read your post.

    Still: I'd remove the timer and bring it on across the line. Part winding start causes more problems that it solves - I've always considered it as pretty much a sales-gimmick.
    Except it lowers the inrush current and the demand charge on the meter.
    The 2nd most important amendment is to protect the 1st....

    Free Air Conditioner Sizing Chart

  6. #6
    Join Date
    Sep 2002
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    I have often wondered just how much though. It's not good for the compressor and what happens when the 1 second timer relay fails open?

    PHM
    -------



    Quote Originally Posted by R123 View Post
    Except it lowers the inrush current and the demand charge on the meter.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  7. #7
    Join Date
    Nov 2006
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    Quote Originally Posted by R123 View Post
    Except it lowers the inrush current and the demand charge on the meter.
    This was a valid concern many years ago. Demand metering was a very common approach to determining power consumption.

    Because of demand metering, you would add capacitance across your lines to adjust your power factor closer to unity, which meant you had a smaller component of "reactive" power, which was power you would pay for, but could not actually use. At unity PF, you could use all of the power you were being billed for.

    Today, most metering setups are the kilowatt hour type, and part winding starts do not help anything.

    Some buildings that have their own power transformers don't have metering at all. They pay a high voltage tariff. Sometimes, the utility will insist that a PF correction is made to their building load, to keep the load from affecting other customers.

    Just a little FYI, because the power business had changed a lot.
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