I must appologize. I did miss speak in my original statement. This bank does have three (3) transformers. They are all single single bushing on the primary. Two are 480v on the low side and the third is 240v on the low side.
Thanks!
Well no, this connection would actually have, 480v, 240v and 120v. There is a open delta at 480v per leg. and then the "upper" part of the A is a 240v delta circuit with the cross-bar of the A being made by the 120/240v transformer. Though the cross-bar is only connected to one of the center...
For the cross-bar of the "A", one end of the winding is connected to the center tap of a 480 bank, but the other side of the winding is only brought out to connect to load, it does not connect to any other windings. Though I'm told that if you were able to place a volt meter between the open...
At a neighboring utility we discovered a very unique connection on a three phase O/H bank. The coneection was open wye-open delta one two single bushing pots. The secondary had 480v L-L with one leg split to get 240v. The oddity came where the one leg was slipt was get 240, the utility also...
After meeting with the transit authority here is the information that we have. The DC line and rails are isolated from ground, essentially "floating". The only DC connection to ground is on 3 driven ground rods that are bonded to DC equipment housings. The AC system has it own grounding grid...
Our utility has been asked by the public transit system to bond our grounded system neutral, which is an AC system, to their grounding grid with serves as a ground for both of their AC and DC equipment. What are the concerns for stray DC current flowing though our AC system?
