CSA,

I may have exaggerated a bit when I said the switches were grilled. But when we opened a couple of them few days ago, we could clearly notice that the printed circuits were affected by heat especially the area around the RJ-45 Port connections. the boards changed colors and the traces started to loose. the metallic box also started to have a dark color from inside. yes those switches return to normal when we use them on other machines (well, most of them !), but for sure all those switches are not reliable anymore.

We do have Vortex tubes available in our warehouse so we don't have to purchase them. the metallic tops of the cabinets are easily removable so we can work safely. we still have concerns about humidity accumulation (although the ambient air is dry). Do you think that using an automatic instrument air filter would be enough to eliminate all the humidity from the air?

We did contact GE for assistance. They promised us to help, we're still waiting for that.

We are measuring the temperature inside the cabinets with a thermometer, and we are monitoring it using the cabinets built-in TCs. the inside temperature now is around 30°c. but it used to reach the alarm threshold (43°C)! we completely removed the air filters and we are keeping the doors opened more frequently. the room temperature is kept around 25°C.

 

badr,

Thank you very much for the quality feedback! It is very much appreciated.

I would check with the vortex tube manufacturer about moisture condensation. If you're using instrument air, I would imagine it's already pretty dry (or should be!). I'm sure the manufacturer makes or sells or recommends a suitable air drying device (which may take some manual adjustment and monitoring to get adjusted correctly and make sure it works properly over time. The risk would seem to me to be condensing the ambient air which is drawn through the vortex tube and cooled--if it is humid/has moisture that might condense....

I tend forget the Mark VIe (and Mark VI) control panels were built using panelized components, so the roof panel could probably be removed to add louvers. I would still recommend putting a hood over the louvers. And, I would not recommend moving the fans to the tops of the doors if you put louvers in the roof panel.

Unless things have changed, the internal control panel temperature is done using the cold junction compensation circuitry on the thermocouple input circuitry. It's a pretty good measure of internal control panel temperature--unless it is affected by heat from I/O packs below it. I've even seen air from an air conditioner discharge that blew through the louvers at the top of the control panel doors directly onto an analog input card of a single control processor with the thermocouple cold junction compensation really play havoc with T/C readings. (The three control processors should have roughly the same temperature, and in that case the cold junction temperature of that processor was about 10 deg F less than the other two.)

Please keep us up to date on the progress!

 

Hello all,

GE sent us a feedback few days ago, they said that the issue of N-tron switches bad behavior is well-known for them and that they issued a TIL since 2014 for that (TIL 1939). they said that the issue is due to bad quality capacitors in their built-in power-supply circuits and is related to electrolyte leakage due to high temperature from those capacitors. this will cause sudden communication failures in the way i described earlier

To solve this issue GE recommends to change the faulty N-tron made switches with the new GE made equivalent switches (they look basically the same with GE logo instead of N-Tron on them).

Hope this will help all of you facing the same problem as we do.

Regards

 

badr,

Thank you again for the great feedback--especially for including the TIL number!

I would still suggest you endeavour to reduce the heat inside the compartment. The three biggest enemies of electronic components are heat, humidity and dust. The more you can reduce the heat, the more you are going to spare all the components inside the turbine control panel--not just the IONET network switches.

Please write back to let us know how you proceed!