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  1. #1

    CVHE FASTPAK PHASE LOSS

    I have a 900 ton Trane CVHE that has a Fastpak control panel conversion and a Robocon VFD starter. The VFD and fastpak were installed in 2000 and have been operating fine until recently. I am now experiencing a Phase Loss failure at startup. We have disabled the voltage monitoring in the UCP setup. I have also swapped the starter panel, CT and power starter transformers, swapped the Chiller module and rewired the CT's and still get a phase loss on start initiation. We have put an O scope on the VFD to verify the SCR gates are firing correctly. We have replaced the 1CR relay and still no luck. The VFD can be started and manually controlled so we are not seeing any issues on the VFD or on the Fastpak to determine where the start issue is. With the VFD running all amp reading on the fastpak are within 2% of each other. We have also increased the starting torque boost in the VFD for a kick start effect no luck. Trane Literature for the fastpak indicates the processor needs to see 20% of motor FLA within .7 to 1 second of a start command. The CH531 has an adjustable time delay to look at the initial inrush but I cannot find any adjustment areas in the Fastpak, though the literature indicates it should be programmable from 1 to 3 seconds. Does anyone have any ideas on a next step to determine how to resolve this issue? Is it possible to disable the phase loss protection, the VFD has in its software?

  2. #2
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    Phase loss cannot be disabled to my knowledge, however, during the initial start the phase reversal protection being the most critical in some UCP2 applications actually performs the phase loss protection.

    Not sure what is causing your issue but can advise correct polarity and wiring of your CT's and the CPT are critical, particulary the 24v supply to the starter module. Would recommend you verify they are exact to the wiring diagram.
    Necessity is the mother of invention

  3. #3
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    Ditto what screwit already said . The polarity and phasing of the CTs and PTs all have to match or you wil get the diagnostic you describe . You can disable phase reversal but not phase loss as such . Depending on how your starter and fastpack transformer are wired you may have to disable momentary power loss as well .
    If it ran until recently has someone monkeyed around with the configuration settings in the fastpack ??? Twinklefingers gets everywhere
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  4. #4
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    Could somebody refresh my memory? What's a Fastpak? (Embarrassing...) Is that a control panel upgrade? To CH531?

  5. #5
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    Fastpack is what they called a UCP2 retrofit panel when you ripped off the old dinosaur pneumatic junk
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  6. #6
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    Pre Tracer CH531 (Or UCP3), Fastpack was the UCP2 version

    Sorry, just saw you beat me to it Healy. Hard to speed type with one finger
    Last edited by Screwit; 08-23-2012 at 04:36 PM. Reason: World's slowest typing
    Necessity is the mother of invention

  7. #7
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    I assume that you have the normal single pole double throw high pres. sw.
    Have you made sure that the normally closed contacts are putting power to the starter module( if in fact you are using a trane starter module).
    In a normal application this will show up as phase loss.

  8. #8
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    Thanks, Healey Nut and Screwit. I feel a little better since that goes back a little ways. I think the OP's reference to CH531 threw me a curve, but reading it again, I believe he was just making a comparison for discussion's sake. Also I have seen the issue of CT and PT polarity pop up years after startup (and no problems), when a tech (me) on a new service agreement finds "Momentary Power Loss" disabled, and he changes it to "Enable". Then the chiller won't successfully start! Until he realizes that the startup tech disabled "Momentary Power Loss" to "get around" the polarity issue. Corrected polarity and all was right again. Or is that finally?

  9. #9
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    Quote Originally Posted by triggerhappy View Post
    I assume that you have the normal single pole double throw high pres. sw.
    Have you made sure that the normally closed contacts are putting power to the starter module( if in fact you are using a trane starter module).
    In a normal application this will show up as phase loss.
    Good point, Triggerhappy. He did say "on start initiation", but that phrase could be open to interpretation....

  10. #10
    PHASE LOSS
    We have disabled the momentary power loss and the phase reversal. I did not try bypassing the NC high pressure safety. The NC switch is closed because I get a momentary start with amp draw readout on the Front panel. It is possible the contacts are not carrying enough current to maintain power to the Trane starter module. The CT's are correctly wired we did verify that and that all electrical connections are tight. I have increased the VFD's starting ramp time to make it an across the line inrush and the chiller will start and operate correctly. We just shouldn't have to hit the SCR's so hard. This is why I think its a start timing issue. We are going to bypass the NC high pressure switch and verify the momentary power loss and phase reversal are still disabled and try again.

  11. #11
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    Unfortunately I do not have a fastpak drawing for reference but for your problem the attached should suffice. The operation of the 5U2 auxillary (line 26) could cause a “phase loss” diagnostic on start-up.

    When a compressor start is initiated the starter module start signal to J8-1 (line 27) is only momentary, for a successful start the start signal must latch in from J8-2 (lines 26).

    May or may not be your issue but worth confirming. CVHE UCP Customer Supplied SSS.pdf

    Disabling the phase reversal protection will have increased your timing for the phase loss diagnostic during starting
    Necessity is the mother of invention

  12. #12
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    "I have increased the VFD's starting ramp time to make it an across the line inrush and the chiller will start and operate correctly"

    If this corrects then verify your CT scaling. For AFD starter what is the starter type configured to?
    Necessity is the mother of invention

  13. #13
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    Quote Originally Posted by Screwit View Post
    Unfortunately I do not have a fastpak drawing for reference but for your problem the attached should suffice. The operation of the 5U2 auxillary (line 26) could cause a “phase loss” diagnostic on start-up.

    When a compressor start is initiated the starter module start signal to J8-1 (line 27) is only momentary, for a successful start the start signal must latch in from J8-2 (lines 26).

    May or may not be your issue but worth confirming. CVHE UCP Customer Supplied SSS.pdf

    Disabling the phase reversal protection will have increased your timing for the phase loss diagnostic during starting
    Screwit is correct the start signal is a momentary closure the starter is then locked in using a lock in set of contacts (usually 2K11 ) on wye delta, then the starter will continue its process , there should be some sort of holding contacts in the AFD to perform the lock in process and allow the AFD to continue to ramp . Sounds to me like this lock in process is not happening . If it tries to start its not the HPC switch . That would not even allow an attempt if it was open at the the time of the start command . It could however be fluttering at start up and causing the diagnostic .
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

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