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  1. #1
    Join Date
    May 2004
    Location
    Salt Lake City/Tooele
    Posts
    2,425

    Quick question for control gurus

    Have a Trane Intellipak SLHFC75 with supply and exhaust VFD operated motors, that was factory set-up for 200v/60/3..but was installed on a building which has a line source of 208-230/60/3. (More info here from my other question asked in the PRO technical forum of this site: http://hvac-talk.com/vbb/showthread.php?t=816032 )

    The factory transformer has a primary spec'd source of 200v to 115v on the secondary. Getting about 123v off the secondary with the obvious higher than spec'd line voltage of 214v to the transformer.

    It has a history of VFD's erratically locking out, mostly during unoccupied weekend parameters. I have NO history with this unit, just stopped by and looked at it the other day and noticed the voltage irregularities.

    My question is, with the VFD's factory installed and most likely with factory set parameters by TRANE, can the higher secondary voltage off of the transformer have any ill effects or cause erratic issues? I am assuming not, but thought I would obviously ask. Just never in my career seen a 200/60/3 factory spec'd system.

    I have sub-contracted Trane to send one of their specialists out to do a whole system diagnostic, which includes the BAC (Trane Tracer and TCI), Statictrac Controls, VFD parameters/programming, VAV's...etc. This is all rocket science to me, but I know after ten years of operation with little more than filter changes, greasing, belts, and erratic vfd faults..it is in need of a system check-out by someone much much more qualified than myself. Not that there is any major issues or complaints, just told the facility owner that it would be a good idea and beneficial to just have the brains of the system looked at and and tweeked if so needed.

  2. #2
    Join Date
    Mar 2005
    Location
    Pacific Time Zone
    Posts
    4,195
    Sounds like the sub is an excellent first means. Nowhere near enough info as the vfd should have some obvious fault codes. Also parameters should be able to be changed easily enough to help minimize nuisance trips. Things may be set too tight.
    During unoccupied and weekends I'd suspect a couple of things - factories/farms nearby running some major equipment causing a volt drop, some kind of unoccupied start command having a conflict (short-cycling).
    As stated by others in your other thread voltage within +/- 10% should not cause a problem with the transformer.
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