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Thread: Ground short ?

  1. #1
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    Ground short ?

    Compressor ----
    Copeland
    3 Ph
    560 Volt
    60Hz

    Equipment
    10 ton split custom made (marine)......

    Story.....

    I fly 120 miles in the gulf of Mexico to work on a solenoid valve .... Change it.... All is good....
    I pulled a vac to 700 microns ....
    Dumped recovered gas back in (on both sides) and when I went to start it tripped main breaker. So I took wires off peckerhead and checked to ground. And alas.... Grounded. So.... Does anyone know why? It worked before.... I didn't turn anything on while in vac ....

    "Duct tape is like the force. It has a light side, a dark side, and it holds the world together."

  2. #2
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    Confused

    Quote Originally Posted by AddMore22 View Post
    Compressor ----
    Copeland
    3 Ph
    560 Volt
    60Hz

    Equipment
    10 ton split custom made (marine)......

    Story.....

    I fly 120 miles in the gulf of Mexico to work on a solenoid valve .... Change it.... All is good....
    I pulled a vac to 700 microns ....
    Dumped recovered gas back in (on both sides) and when I went to start it tripped main breaker. So I took wires off peckerhead and checked to ground. And alas.... Grounded. So.... Does anyone know why? It worked before.... I didn't turn anything on while in vac ....
    When you dumped the recovered gas back in both sides was it liquid?

  3. #3
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    I think u charged liquid in suction side. compressor was probably compressing liquid refrigerant.

  4. #4
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    Topping off the compressor sump with liquid will trash your valves but I doubt it caused an immediate short. Is that for a drive house ?

  5. #5
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    Was the solenoid liquid valve leaking or just inoperable ?

    Did you check it before you replaced the solenoid valve ?

  6. #6
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    Thread Starter
    Quote Originally Posted by commtech77 View Post
    Was the solenoid liquid valve leaking or just inoperable ?

    Did you check it before you replaced the solenoid valve ?
    It was just leaking .....
    It has a receiver.
    Not worried about liquid in suction
    It was in a VFD house.

    "Duct tape is like the force. It has a light side, a dark side, and it holds the world together."

  7. #7
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    What is a "VFD house" ? What kind of device interrupts power to the compressor ? Is it a contactor or something else ? What kind of crancase heater, if any ?

  8. #8
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    Thread Starter
    "VFD" - Variable Frequency Drive- its on a drilling rig.

    It's a 3 phase 600 volt ... So no cap...

    Crank case heater has been disabled prior this.

    I guess my main question is this ...
    Is there any way the insulation in the windings of a compressor be compromised due to a vacuum?

    "Duct tape is like the force. It has a light side, a dark side, and it holds the world together."

  9. #9
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    I thought "VFD" probably meant Variable Frequency Drive, but what exactly is meant by "VFD house" ? EVERYTHING has VFD ? Including compressor ? I realise it has no capacitor, at least I've never heard of a cap used to interrupt power as a means of starting and stopping something, like a compressor... The reason I ask what does start and stop, or interrupt the power to, the compressor is to determine if it is a solid state device ( like a soft starter, or a VFD ). It seems unlikley that it would be anything other that a simple contactor on something this size, but I just wanted to rule it out.

  10. #10
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    Actually it's a 10 ton with 2 5 ton Copland scrolls. And one legs is always hot with the other two going in a contractor.

    "Duct tape is like the force. It has a light side, a dark side, and it holds the world together."

  11. #11
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    Quote Originally Posted by Nuclrchiller View Post
    I thought "VFD" probably meant Variable Frequency Drive, but what exactly is meant by "VFD house" ? EVERYTHING has VFD ? Including compressor ? I realise it has no capacitor, at least I've never heard of a cap used to interrupt power as a means of starting and stopping something, like a compressor... The reason I ask what does start and stop, or interrupt the power to, the compressor is to determine if it is a solid state device ( like a soft starter, or a VFD ). It seems unlikley that it would be anything other that a simple contactor on something this size, but I just wanted to rule it out.
    Its a seperate building on land and offshore rigs that houses all of the motor control, fuses, controls and VFDs for the DC motors on the rig.

    High heat load and a critical part of any rig. You lose AC and the drives overheat and they have to stop drilling.

    A multi million dollar operation is put on hold until you get the AC repaired.

    Roughnecks and tool pushers looking at you sideways.

  12. #12
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    Quote Originally Posted by AddMore22 View Post
    Actually it's a 10 ton with 2 5 ton Copland scrolls. And one legs is always hot with the other two going in a contractor.
    Was unit powered up ( even though not running ) during evacuation ?

  13. #13
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    Quote Originally Posted by commtech77 View Post
    Its a seperate building on land and offshore rigs that houses all of the motor control, fuses, controls and VFDs for the DC motors on the rig.

    High heat load and a critical part of any rig. You lose AC and the drives overheat and they have to stop drilling.

    A multi million dollar operation is put on hold until you get the AC repaired.

    Roughnecks and tool pushers looking at you sideways.
    Ohhh..., OK. Thanks.

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