York YS Chiller Ground Fault

[yorktek37]

I was thinking maybe this is caused by a bad line reactor, so after some googling I found this. As you know a GFI is looking for current leakage, so if the components test out ok, I think you need to look at how the motor is grounded or something along these lines.


PWM Drives — Measurement 5
Leakage currents (common mode noise)

Leakage currents
Leakage currents (common mode noise) capacitively coupled between the stator winding and frame ground will increase with PWM drives as the capacitive reactance of the winding insulation is reduced with the high frequency output of the drive. Another leakage current path may exist in the capacitance created when the motor cables are placed in a grounded metal conduit. Therefore, faster rise times and higher switching frequencies will only make the problem worse.

It should also be noted the potential increase in leakage currents should warrant close attention to established and safe grounding practices for the motor frame. The increase in leakage currents can also cause nuisance tripping of ground fault protection relays, override 4 to 20 mA control signals, and interfere with PLC communications lines.

Measure common mode noise by placing the current clamp around all three motor conductors. The resultant signal will be the leakage current.

A common mode choke can be used to reduce leakage currents (see Figure 5A). Also, special EMI suppression cables can be used between the drive output and the motor terminals. The copper conductors of the cable are covered with ferrite granules, which absorb the RF energy and convert it to heat. Isolation transformers on the ac inputs will also reduce common mode noise.

http://www.davis.com/techinfo/techin...rement-ASD.htm

All fine and dandy but is a solid state starter. IE (soft-start) without the contactors.
More than likely it the driver board. Hardly ever do the hockey pucks go bad. You can test then with a 9 volt battery. You just need to forward bias the scr to see if it conducts. There are instructions on how to test phase control scr's on the net. It takes more than what a meter puts out though. They are actually a network of scr's to handle the current.

[curlydogmaster]

Before I started on the troubleshooting the L3 upper trigger section caught my eye (2nd from the right) in the wide photo.
The other two photos are closeups of the L3 lower and upper trigger sections (good vs. bad).
I'm really confident that's the problem but I started through the troubleshooting flow chart anyway with the motor disconnected because the GFI breaker won't let it start for any more that .4 seconds.
All the tests up to page #28 were good but when I got to the part that the motor has to start, I'm stuck except the only 2 possible outcomes to any of the tests are "Replace SCR Assy" or "Replace Trigger Board".
I'm ordering a Trigger Board and we'll see if I also have a faulty SCR...
Thanks all!

[yorktek37]

r-87 definitaly does look like it could have gotten hot before. However they do run pretty hot. I think that is a shunt resistor to contril the gate current on the scr. It could be holding the scr on but it would be a phase fault or a half phase trip. I think that the big GFCI's will treat a half phase conduction as a ground fault. Good luck on this one. However in your defense if there is a bad scr brick they will usuallt\y take the driver board out also. Try to find someone that repairs these new inverter welders and se if they have an scr tester to test out the pucks before you try the new driver board. I may have an old one in the storage is you want to test it out first. It is of no use to me. I would not trust it for anything but testing. I will look. I will send you my contact info by e-mail. Call me around 9 am CST.

[yorktek37]

r-87 definitaly does look like it could have gotten hot before. However they do run pretty hot. I think that is a shunt resistor to contril the gate current on the scr. It could be holding the scr on but it would be a phase fault or a half phase trip. I think that the big GFCI's will treat a half phase conduction as a ground fault. Good luck on this one. However in your defense if there is a bad scr brick they will usuallt\y take the driver board out also. Try to find someone that repairs these new inverter welders and se if they have an scr tester to test out the pucks before you try the new driver board. I may have an old one in the storage is you want to test it out first. It is of no use to me. I would not trust it for anything but testing. I will look. I will send you my contact info by e-mail. Call me around 9 am CST.

The only other way you could be getting this fault is through the coolant. Make sure it is not very conductive. If I remember right the coolant comes in contact with the 480 in a few places. I cannot swear to this. I have never tested it and I have never torn into one of the blocks but there is a reason that they used distilled water a long time ago. I think it was because it has a low conductivity. SSS Coolant does not have glycol in it as many believe. It has some silicates and nitrates in it and the rest is either distilled water or DI Water. Take a wire and drop it in the fill tube and test it to ground. I'm not trying to mislead you but if the moter checks out then this could be it. Let me know in the morning.

[curlydogmaster]

Wrap-Up:
The the burned trigger had no output
The SCR's ohm'ed good so I ordered a new trigger board.
Installed it today and the machine purrs like a kitten.

Thanks again to all!

[yorktek37]

excellent

[Entropie]

The only other way you could be getting this fault is through the coolant. Make sure it is not very conductive. If I remember right the coolant comes in contact with the 480 in a few places. I cannot swear to this. I have never tested it and I have never torn into one of the blocks but there is a reason that they used distilled water a long time ago. I think it was because it has a low conductivity. SSS Coolant does not have glycol in it as many believe. It has some silicates and nitrates in it and the rest is either distilled water or DI Water. Take a wire and drop it in the fill tube and test it to ground. I'm not trying to mislead you but if the moter checks out then this could be it. Let me know in the morning.

There is no connection between the coolant and the electrical power! The reason why deinonized water is used, is corrosion. But you should never use anything else in the system then the original coolant, you should no dilute it or do any thing else to it. I know the stuff is expensive but a dead starter is far more expensive...................

[yorktek37]

you got that right. The coolant used in the ycav and the yciv is a glycol base. Under no circumstances should anything else be added. I have heard of people using dexcool in it. From what I was told it will cause permanent damage to the pump seal and the o-rings inder the IGBT's. I have had some problems with bacteria growing in the SSS coolant loop. The only thing that I found that will kill it is a Benzalkamonium chloride disenfectant Or even easier to get, Waterbed conditioner. Run it for about 20 minutes. Vacume it out and flush it with DI water (several times) and then fill it up with coolant. Everyone had told me to use antifreeze to kill it. It wont. Usually comes back in 2 months. The disinfectant works great and it will not attack any of the plastics or any of the metals.

[pradeeph]

Before I started on the troubleshooting the L3 upper trigger section caught my eye (2nd from the right) in the wide photo.
The other two photos are closeups of the L3 lower and upper trigger sections (good vs. bad).
I'm really confident that's the problem but I started through the troubleshooting flow chart anyway with the motor disconnected because the GFI breaker won't let it start for any more that .4 seconds.
All the tests up to page #28 were good but when I got to the part that the motor has to start, I'm stuck except the only 2 possible outcomes to any of the tests are "Replace SCR Assy" or "Replace Trigger Board".
I'm ordering a Trigger Board and we'll see if I also have a faulty SCR...
Thanks all!

i am also face same problem.....i was checked the SCR out put .....one phase showing 120v...i need conform that fault came from trigger board or SCR module???????

please help mee....