york screw chiller

happy christmas guys ive got a problem with the yeas sa chiller starting.the star contactor and line pull in and ct reads the amps but after a couple of seconds the delta contactor pulls in and then it drops out. With current fault. Because its reading less then 5% of the fla.is there any way of increasing the time limit of that safety. Because the chiller has full gas charge and compressors are fine. Did all simulation tests every thing runs ok electrically. Checked factory settings they are all ok.all safeties are ok. Any ideas or help would be greatly thankfull.and is there any password to change the amperage setting in the panel

Whats the type of screw compressor? Star delta must to change 0.7-1 sec.

Its hanbell screw. Star delta. 4 seconds change over

When the microprocessor initiates a start signal to run a
compressor, it runs in star for 4 to 10 seconds
depending upon motor current as sensed by the
microprocessor. Normally, the transition to delta takes
10 seconds if current is below 125% FLA. If motor
current exceeds 125% FLA, the transition is made to
delta after a star run time of at least 4 seconds

http://www.mediafire.com/view/n76sya...OPER.MAIN..pdf

http://www.hanbell.com/en/R/TechManual/RC2-TM.pdf

59 page

I dont trust york, i trust IOM and SM from manufacture.
If that manual from another compressor, find yours)

have you checked current transformer and its resistance?your starting 5% FLA measured on clamp meter or from display board.

Hi thankyou install. Rusbuka and moideen i havent checked the ct resistance but the display reads different from clamp meter the clamp meter readings are higher and i dont know how to calibrate it

Quote:

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Originally Posted by GHAZ

Hi thankyou install. Rusbuka and moideen i havent checked the ct resistance but the display reads different from clamp meter the clamp meter readings are higher and i dont know how to calibrate it

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check the ct resistance, it is between 40-45. if there is any error,i thing the replacement of ct is the option,not calibration.

Ghaz.
As far as I know and therefore could be wrong!
But I think the display readout will never correlate with a clamp meter on a York system.
As it is a calculation within the software.
At least on some of the ones I have looked at in the past!
I know there are others that will know more about this on forum.
So hopefully they will chip in?
Check the operation of the Auxiliary contacts on the side of the Star Delta contactors.
Or check that your delta contacts and supplies are correct.
I believe the software is not seeing an amperage being drawn for it to drop out the way you describe.
Good Luck.
Grizzly

I know more tricks, but I cant describe them. My english very bad. First of all try to push contactors by hands without power on chiller. Offen was trouble with mechanic in contactors. And one fase not connecting.

Quote:

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Originally Posted by RusBuka

I know more tricks, but I cant describe them. My english very bad. First of all try to push contactors by hands without power on chiller. Offen was trouble with mechanic in contactors. And one fase not connecting.

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hi rusbuka, as per the first post of mr.ghaz, the FLA is only 5%.if the contactor is not proper holding it will take high amps, if the contactor auxiliary is not working it will generate transition alarm. But the display reading and actual clamp meter reading is different. So I think the CT is defective or CT wiring needs to be checked. If again the same trouble is persisting, we can think the next step.

swap ct with other circuit
check as Rusbuka says, this is a known fault on these chillers
also check the contactors are feeding 3 phases when pulled in, pitting will cause this fault
is the compressor unloaded when starting?
The history is not quick enough to record actual amps at shutdown, you need ammeter to confirm that the compressor is not tripping on too high current as well

Quote:

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Originally Posted by moideen

hi rusbuka, as per the first post of mr.ghaz, the FLA is only 5%.if the contactor is not proper holding it will take high amps, if the contactor auxiliary is not working it will generate transition alarm. But the display reading and actual clamp meter reading is different. So I think the CT is defective or CT wiring needs to be checked. If again the same trouble is persisting, we can think the next step.

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Do you not read the other posts?
Grizzly

hi guys the contactor tips are good no pitting, the auxiliarys are all ok, the wiring is good and tight,3 phases are there 415v, and 243v phase to earth.the readings on compressors is all equal ,phase rotation is ok and relay is good,liquid line s/valve is ok, the pressure equalization valves open and shut ok with no bypass or letby,