leitmotif
Member
OK so here is what I know
Have Fed Pacific 15KVA transformer
Hi side delta with corner ground.
Hi side nominal 480.
Hi side windings are tapped.
Low side 120 208 wye 4 conductor. Volt readings taken on cord cap - 4 pole. Phases are arbitrarily numbered 1 thru 3 and ground is ground.
Phase to phase 1 to 2 211.8
1 to 3 211.9
2 to 3 211.6 all 211 plus or minus 0.1
Phase to ground
1 84.4
2 127
3 183
I have not read the high side voltages but from experience know they are pretty close in other portions of system and am ASSUMING they are here too.
I DID check continuity from ground pin of cord cap to frame of transformer. It was a good reading but I did not record it.
However all that tells me is that the ground conductor is good AND it is connected to transformer mounting bracket. I have no idea if it is tied in to the main system ground.
I have not opened it up and do not intend to do so until I have an idea of what to look for and not do some explore hunt n peck operation. Also boss says it is working do not fix what aint broke. At this time we do not intend to feed any single phase loads from this.
It supplys only a single motor load.
Seems to me that with phase to phase values all consistant that
all the tap settings are the same
the star point connection is good
Went in to Tierney transformer and asked them about this. They are puzzled but think that maybe the ground connection is bad.
IF I am lucky the contractor pulled in a ground conductor (FAT CHANCE) so all I can rely on is conduit grounding.
I feel a little better that a transformer mfr is puzzled
but,,
do you guys have any ideas of what to look for??
Dan Bentler
Have Fed Pacific 15KVA transformer
Hi side delta with corner ground.
Hi side nominal 480.
Hi side windings are tapped.
Low side 120 208 wye 4 conductor. Volt readings taken on cord cap - 4 pole. Phases are arbitrarily numbered 1 thru 3 and ground is ground.
Phase to phase 1 to 2 211.8
1 to 3 211.9
2 to 3 211.6 all 211 plus or minus 0.1
Phase to ground
1 84.4
2 127
3 183
I have not read the high side voltages but from experience know they are pretty close in other portions of system and am ASSUMING they are here too.
I DID check continuity from ground pin of cord cap to frame of transformer. It was a good reading but I did not record it.
However all that tells me is that the ground conductor is good AND it is connected to transformer mounting bracket. I have no idea if it is tied in to the main system ground.
I have not opened it up and do not intend to do so until I have an idea of what to look for and not do some explore hunt n peck operation. Also boss says it is working do not fix what aint broke. At this time we do not intend to feed any single phase loads from this.
It supplys only a single motor load.
Seems to me that with phase to phase values all consistant that
all the tap settings are the same
the star point connection is good
Went in to Tierney transformer and asked them about this. They are puzzled but think that maybe the ground connection is bad.
IF I am lucky the contractor pulled in a ground conductor (FAT CHANCE) so all I can rely on is conduit grounding.
I feel a little better that a transformer mfr is puzzled
but,,
do you guys have any ideas of what to look for??
Dan Bentler
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