wtdoor67
06-13-2010, 09:27 PM
This is a rehash but I'll put it up again.
The system was a 3 phase grounded 7200 volt Delta. The problem was at an irrigation bank. It was a Delta/Wye hookup. Voltage was 277/480. Our serviceman (not the sharpest) was sent out. Sortofa non-climber. The complaint was periodically the pump would kick off as the breaker was tripping. The customer had a very competent electrician check things and his verdict was it was on the power co's part.
Our non-climbing (sort of) serviceman went, glanced up the pole and because one pot appeared to have a lot of oil on it, pronounced it bad. In the local warehouse we didn't have a replacement pot of this size. I think it was a 75 KVA. It was evening and upon negotiating with the rancher it was decided he could wait until the following day as we'd change it first thing the following morning. A warehouse man was sent early the next morn. to pick up a pot and meet our 3 man crew at the location somewhere near after 0700, which was when we started.
The truckey, myself and the foreman drove to the location. I climbed the pole and noticed all the copper crimpit connections to the ground wire were baked out pretty good. I felt the pots with my bare hand. They were all normal feeling. Earlier voltmeter readings did show a pretty bad imbalance in readings. I commented to the foreman that I thought the oily pot wasn't bad, but we put up the new one anyway. Still the same readings.
The nearest ranch house was visited and I climbed the transformer pole. I jerked the pot off and with a couple of hot clamps and a piece of #6 jumped it over to the other hot phase. It was about 106 volts with a pretty normal 120 or so volts on the original phase. I told the foreman that it had to be a problem between here and the sub. I said probably that cap bank about a half a mile away. Another trouble call came and I was sent alone about 40 miles away and the foreman and trucky were left to deal with this problem. I think the serviceman had called in sick or something. How handy.
I went North and for about 3 plus hours I heard the foreman calling the meter relay boss in Casper and visiting the regulators and so on. All sorts of things were tried.
Finally the cap bank was visited and it was discovered a fuse was blown on the cap bank. The remaining fuse was opened and magically the voltage was balanced at the 277/480 bank. Eventually we changed the bad cap.
The system was a 3 phase grounded 7200 volt Delta. The problem was at an irrigation bank. It was a Delta/Wye hookup. Voltage was 277/480. Our serviceman (not the sharpest) was sent out. Sortofa non-climber. The complaint was periodically the pump would kick off as the breaker was tripping. The customer had a very competent electrician check things and his verdict was it was on the power co's part.
Our non-climbing (sort of) serviceman went, glanced up the pole and because one pot appeared to have a lot of oil on it, pronounced it bad. In the local warehouse we didn't have a replacement pot of this size. I think it was a 75 KVA. It was evening and upon negotiating with the rancher it was decided he could wait until the following day as we'd change it first thing the following morning. A warehouse man was sent early the next morn. to pick up a pot and meet our 3 man crew at the location somewhere near after 0700, which was when we started.
The truckey, myself and the foreman drove to the location. I climbed the pole and noticed all the copper crimpit connections to the ground wire were baked out pretty good. I felt the pots with my bare hand. They were all normal feeling. Earlier voltmeter readings did show a pretty bad imbalance in readings. I commented to the foreman that I thought the oily pot wasn't bad, but we put up the new one anyway. Still the same readings.
The nearest ranch house was visited and I climbed the transformer pole. I jerked the pot off and with a couple of hot clamps and a piece of #6 jumped it over to the other hot phase. It was about 106 volts with a pretty normal 120 or so volts on the original phase. I told the foreman that it had to be a problem between here and the sub. I said probably that cap bank about a half a mile away. Another trouble call came and I was sent alone about 40 miles away and the foreman and trucky were left to deal with this problem. I think the serviceman had called in sick or something. How handy.
I went North and for about 3 plus hours I heard the foreman calling the meter relay boss in Casper and visiting the regulators and so on. All sorts of things were tried.
Finally the cap bank was visited and it was discovered a fuse was blown on the cap bank. The remaining fuse was opened and magically the voltage was balanced at the 277/480 bank. Eventually we changed the bad cap.