York YR Soft Starter - HELP

[centrecipew]

Hi All,
I need some help Please!!
I currently working on a York Screw Chiller YR series 150 with water cooled condenser and Flooded Evaporator. It has a large Frick Semi Hermetic.
I work for another Manufacturers service Dept and have access to the York Bulletins etc. Amazing what a cup of Tea gets access to!
The chiller suffered a Melt Down in the Motor terminal box.
Now that all the Motor Terminals, Leads and Links have been replaced I have re-energised the control circuit and have an instant "Phase A SCR Shorted" Message on the Optiview Panel.
I have followed the "York" bulletin test instructions to the letter and still am not able to make a conclusive decision as to wether the fault is in fact a faulty SCR or the LCSSS Logic Board.
All recorded "Gate" tests show the resistance values to be within expected Tolerances.
All tests carried out have been done at the panel with the motor leads disconnected using a Fluke77 Digital Meter. Can I use a "Megger" across T1-L1 @250v to check the SCR is Shorted?
The motor windings are Balanced and Continuos and have 1000Ohm resistance to Earth at 500v. Working on this unit until now has been a pleasure, it seems really well put together. It`s sister chiller was saved from a similar meltdown by removing the Self Amalgamating tape at the terninal studs and a Re-torquing. First time in 6 years! And yes they were not much more than Hand Tight!! We have only just got the maintenance on these units.
Any thoughts and suggestions of a technical nature would be greatly appreciated.
Thanks,
Rob
PS: York Parts Department here in UK have been really helpfull and organised!!

[goshen]

Hi
check all scr and make sure they are not shorted ,then you can cancel this protection via the screen control board ,i would only do this if you are 100% sure the scr's are ok !!!
if u need any more info i have all the york literrature regarding soft starters on this model.
in my own case we had a faulty starter that actully all scr's were shorted so we fit an external soft starter that works fine .
good luck

[centrecipew]

Hi Goshen,
How did you confirm that the SCR` were shorted. I have measured resistance between T1 and L1 on all the SCRs and have got quite a high resistance in both directions. Resistance in excess of 2800 ohms. When I turn the power on I get 238 volts between each L1 and earth terminal. The same as the T1 and earth.
Also space here is very limited so I have no room for external soft starter.
I have a local company on standby to rebuild the SCRs once I can confirm that they are shorted. The SCRs are also available as single Items from York-JCI.
Cheers,
Rob

[goshen]

Hi Goshen,
How did you confirm that the SCR` were shorted. I have measured resistance between T1 and L1 on all the SCRs and have got quite a high resistance in both directions. Resistance in excess of 2800 ohms. When I turn the power on I get 238 volts between each L1 and earth terminal. The same as the T1 and earth.
Also space here is very limited so I have no room for external soft starter.
I have a local company on standby to rebuild the SCRs once I can confirm that they are shorted. The SCRs are also available as single Items from York-JCI.
Cheers,
Rob

HI :
mail me i used yorks guide !

[GHAZ]

hi which starter model do you have

[centrecipew]

Hi, The starter is a "York" LCSSS liquid cooled Soft Starter. FLA 400amps 50hz 400vlots.
Cheers,
Rob

[GHAZ]

hi rob check your email

[centrecipew]

Hi All Again,
Following a return visit to site.
I have tested the SCRs and found that they are NOT shorted.
However the Gate Driver output is way out of the recomended resistance values.
I am now almost certain that the Logic Board is at Fault.
A call to JCI is in order to get a new one I Think.

The Starter is a SSS14LCE-50B.

Any further recomendations regarding further tests would be most appreciated.

Have a good weekend all!
Rob

[centrecipew]

Hi Guys,
Thanks for your replies and advice.
The unit is now running. I reconnected the motor leads and energised the panel.
No Faults appeared and the start sequence was initiated. YUP the bloody thing started and run with no problem at all.
I wonder if the starter was in fault due to the windings being disconnected??
Needless to say the customer is thrilled that no further expense is required.
Once again thanks for the help and "Keep Chilling"
Rob

[sedgy]

hi all, just a quick point
has the cc heater been on long?
on theses modern w- chillers do they have atemp sensor to detect if cch has been on ¿?

[goshen]

hi all, just a quick point
has the cc heater been on long?
on theses modern w- chillers do they have atemp sensor to detect if cch has been on ¿?

 hi
Yes most of these units monitor oil temp and will delay the start until oil reaches set point