PDA

View Full Version : how sensitive are step-downs



reppy007
04-22-2012, 10:09 PM
I cant be the only one that has seen this happen,so Ill give you the short version of the story as I remember it,and see if others have had similar situations.Years ago we had a tropical storm blow in which was called Allison,it produced more rain then any hurricane I have ever seen...a day or two after the storm we were sent up to the northern portion of our area to get lights on.this one area was a little hilly and there happened to be a few urd loops that were fed by step down transformers.19.9/7200.....being hilly meant that there also were some low areas and there was no shortage of live-fronts....keep in mind that there was still plenty of water in the area and in those low areas.....well believe it or not there were guys shooting the step/downs,and what was happening is that they were burning them up left and right,due to faults on those loops or the high water,and the usual bad wire under the red hoods....it took alot of yelling to finally teach these guys that shooting them and replacing them wasnt the right solution..........its been my experiences ,and there are a few that the step down transformers are really sensitive,seems like more than the usual transformers to me,whats you guys take on this one?

rob8210
04-23-2012, 05:48 PM
We had a few step downs that would barely last a year, but that was almost 20 years ago and they were overhead. Welcome back, Reppy, where have you been hiding?

Pootnaigle
04-23-2012, 07:20 PM
Ummmmmmmm as the voltages increase and the windings decrease a Fault iza a real prollem on any transformer. So if you are relying on fuses to clear the circuit , It may take a long time in lectric time. If however the circuit is protected by a recloser it shoud take only a few cycles to clear, Minimumizing the amount of time a transformer is exposed to a fault. Them faults wreak havoc on a translater of any kind

reppy007
04-23-2012, 08:54 PM
Ummmmmmmm as the voltages increase and the windings decrease a Fault iza a real prollem on any transformer. So if you are relying on fuses to clear the circuit , It may take a long time in lectric time. If however the circuit is protected by a recloser it shoud take only a few cycles to clear, Minimumizing the amount of time a transformer is exposed to a fault. Them faults wreak havoc on a translater of any kind

Thanks Poot,I did think of the windings but at times they seemed extra sensitive,and would burn up at times that i wouldnt have thought that they would,even seen a few that had coppered out barrels on the load side,and seen a fair share with coppered out barrels on the line side,and you might not believe that ive seen just a few with both sides coppered out..........which makes me wonder what that engineer that designed that foolish nightmare is doing today.You never know what those people can dream up next.