Message Board Thread - "Transformer abnormality or anomoly?"

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Transformer abnormality or anomoly? Sharonna 10/1/2009
I have a Westinghouse (installed mid 80's) 75 kVA transformer (Primary 480 Y120) that exists in a high ambient temperature area (Phoenix AZ 114+ in the summer) and it's location is only cooled by (high humidity) air wash systems during the summer months. I've been Infrared-ing 200+ county buildings for five years now and I have never seen a transformer coil look quite like this, I would have possibly passed it off as a reflection off the bolt if it did not have that halo going around the B phase coil at the tap level. The temperatures are not alarming, however, this transformer feeds a panel that operates a high security detention facility i.e., controls, etc. I thought I would throw it out there for feedback. I have very few buildings with these air wash systems, so shooting with the humidity levels you see here is not common for me and I wondered if this could be a contributing factor. I threw in an IR of C phase coil of the same transformer which is typically what I see several hundred times a year. The visual inspection looked good B - phase looked better than A or C at the tap connections. FYI...the amp draws were primary side A - 12.7, B - 11.5, C - 8.6 and the secondary side A - 24.0, B - 31.8, and C - 15.1 with the Neutral at 11.8 amps. There are alot of electronic relay cabinets in the same electric room as well as wireless listening devices throughout this location and was 'him-hawing' around about possible transmission interference? Usually the camera acts weird when I'm shooting if that's an issue, and it did not when this was shot. Please help with ideas or thoughts because if this Xfrmr went down after I shot this, I might end up wearing pink underwear myself!?#@! Signed: "I never saw something like this in my 5 years of infrared imaging here I guess that's what keeps my job so interesting"......thanks in advance for your time and input - Sharon B. Phoenix AZ.
 
Re:Transformer abnormality or anomoly? IRJay 10/1/2009
Looks like a loose tap connection on that finger. I assume that this is still covered with varnish from the factory? I have seen these before where the factory has not provided sufficent tightening to the bolts.
 
Re:Transformer abnormality or anomoly? certir 10/3/2009
Sharonna wrote:
a Westinghouse (installed mid 80's) 75 kVA transformer (Primary 480 Y120) that exists in a high ambient temperature area (Phoenix AZ 114+ in the summer) and it's location is only cooled by (high humidity) air wash systems during the summer months. I've been Infrared-ing 200+ county buildings for five years now and I have never seen a transformer coil look quite like this, I would have possibly passed it off as a reflection off the bolt if it did not have that halo going around the B phase coil at the tap level. The temperatures are not alarming, however, this transformer feeds a panel that operates a high security detention facility i.e., controls, etc. I thought I would throw it out there for feedback. I have very few buildings with these air wash systems, so shooting with the humidity levels you see here is not common for me and I wondered if this could be a contributing factor. I threw in an IR of C phase coil of the same transformer which is typically what I see several hundred times a year. The visual inspection looked good B - phase looked better than A or C at the tap connections. FYI...the amp draws were primary side A - 12.7, B - 11.5, C - 8.6 and the secondary side A - 24.0, B - 31.8, and C - 15.1 with the Neutral at 11.8 amps. There are alot of electronic relay cabinets in the same electric room as well as wireless listening devices throughout this location and was 'him-hawing' around about possible transmission interference? Usually the camera acts weird when I'm shooting if that's an issue, and it did not when this was shot. Please help with ideas or thoughts because if this Xfrmr went down after I shot this, I might end up wearing pink underwear myself!?#@! Signed: "I never saw something like this in my 5 years of infrared imaging here I guess that's what keeps my job so interesting"......thanks in advance for your time and input - Sharon B. Phoenix AZ.
I too would call this a classsic "High resistance connection". We see these about 4 times a year. The imbalance on the secondary side may be a factor also. I would have taken a load reading on the tap conductors also. But the lack of high temps on the tap conductor would seem to rule out loads as an issue. I am surprised that with 5 years under your belt you would not recognise this for what it is.
 
Re:Transformer abnormality or anomoly? hruiz 10/5/2009
its a conection tab lossen ang geenerate the high temp

regards

hector Ruiz
ditek de mexico
 
Re:Transformer abnormality or anomoly? CNIR 10/6/2009
Sharonna wrote:
a Westinghouse (installed mid 80's) 75 kVA transformer (Primary 480 Y120) that exists in a high ambient temperature area (Phoenix AZ 114+ in the summer) and it's location is only cooled by (high humidity) air wash systems during the summer months. I've been Infrared-ing 200+ county buildings for five years now and I have never seen a transformer coil look quite like this, I would have possibly passed it off as a reflection off the bolt if it did not have that halo going around the B phase coil at the tap level. The temperatures are not alarming, however, this transformer feeds a panel that operates a high security detention facility i.e., controls, etc. I thought I would throw it out there for feedback. I have very few buildings with these air wash systems, so shooting with the humidity levels you see here is not common for me and I wondered if this could be a contributing factor. I threw in an IR of C phase coil of the same transformer which is typically what I see several hundred times a year. The visual inspection looked good B - phase looked better than A or C at the tap connections. FYI...the amp draws were primary side A - 12.7, B - 11.5, C - 8.6 and the secondary side A - 24.0, B - 31.8, and C - 15.1 with the Neutral at 11.8 amps. There are alot of electronic relay cabinets in the same electric room as well as wireless listening devices throughout this location and was 'him-hawing' around about possible transmission interference? Usually the camera acts weird when I'm shooting if that's an issue, and it did not when this was shot. Please help with ideas or thoughts because if this Xfrmr went down after I shot this, I might end up wearing pink underwear myself!?#@! Signed: "I never saw something like this in my 5 years of infrared imaging here I guess that's what keeps my job so interesting"......thanks in advance for your time and input - Sharon B. Phoenix AZ.
IT WOULD APPEAR TO BE A HIGH RESTANCE/LOOSE/ WITH THE POSSIBLITY OF A SMALL AMOUNT OF CORROSION BETWEEN CONNECTION POINTS (FROM THE HIGH HUMIDY AIR WASH IF NOT SEALED AT THE FACTORY OR IF THE TAPS WERE CHANGED). THE CURRENT READINGS AS TAKEN ON BOTH THE PRIMARY & SECONDARY SIDE, WERE THEY PERFORMEND WITH A RMS CURRENT METER? IF THE LOAD SIDE FEEDS A HIGH NUMBER OF "SWITCHING" POWER SUPPLIES AND/OR VARIBLE SPEED MOTOR DRIVES THE ACTUAL CURRENT READINGS WITH A NON-RMS METER (CHEAP RADIO SHACK/FLUKE) WILL BE MUCH LOWER THAN THE ACTUAL CURRENT WITH THE ADDITION OF THE 60HZ HARMONICS. WHAT WAS THE THD THAT WAS MEASURED? YOU DID NOT REPORT IF IS THERE WERE VOLTAGE/CURRENT REGULATING DEVICES PRESENT (EXTERNAL CAPACITORS OR INDUCTOR TYPE REGULATORS). HOW IS THE DUST BUILD UP (COMPOSITION OF THE DUST?)ON THE TXFR COILS AND CONNECTIONS? THE ISSUE SHOULD BE BE REVIEWED BY A PERSON WITH "POWER QUALITY" EXPERIENCE.

CNIR
 
Re:Transformer abnormality or anomoly? Dude 7/7/2010
Sharon that looks like a HRC but there could be other issues. Just courious what you found.
 
Re:Transformer abnormality or anomoly? TDLIR 7/7/2010
apart from the obvious connection issue. You may also want to look at this transformer with a waveform analyzer to determine if it is being affected by harmonics.
 


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