Electrician Talk banner
21 - 40 of 80 Posts

·
Registered
Residential, lite comm., Industrial
Joined
·
147 Posts
Discussion Starter · #21 ·
It is a normal metal building on a concrete slab. standard construction
This is the pole transformers that you are mentioning?? From the utilities??
If yes.
The Center tap does it have a bare conductor to the shell with a taped conductor/that circular runs behind the pole transformer to attach to a lower common wire, per transformer?
HOLD UP, no center taps. yes, these are the pole transformers/ POCO xfmrs. 480V 3 phase. the secondary of the pots has ONLY 2 connections. #1 is to the other 2 pots and then ground #2 is to the 3 hot wires to the mill
 

·
Registered
Residential, lite comm., Industrial
Joined
·
147 Posts
Discussion Starter · #22 ·
GUYS .... READ THE ORIGINAL POST OR THIS ONE : utility feed to the mill is 3 hot wires, no ground , no neutral

WHAT IS THE COMMON NAME FOR THIS CONFIGURATION ???
 

·
Band Member
DIYer Extrodinaire
Joined
·
7,705 Posts
GUYS .... READ THE ORIGINAL POST OR THIS ONE : utility feed to the mill is 3 hot wires, no ground , no neutral

WHAT IS THE COMMON NAME FOR THIS CONFIGURATION ???
It's Delta. Re-read posts #2 and most important #7
 
  • Like
Reactions: SWDweller

·
Registered
Residential, lite comm., Industrial
Joined
·
147 Posts
Discussion Starter · #25 ·
I appreciate the interest. Yes it is rare, that is because it is at least as old as 1960, that is why I dont know what to call it. I guess i should say im looking for someone who is already retired, they might be old enough to have heard the common name for it
 

·
Registered
Electrical Contractor
Joined
·
2,779 Posts
the secondary of the pots has ONLY 2 connections. #1 is to the other 2 pots and then ground #2 is to the 3 hot wires to the mill
Grounded Wye. What do I win?
 
  • Like
Reactions: 460 Delta

·
Band Member
DIYer Extrodinaire
Joined
·
7,705 Posts
@Dennis Alwon or another moderator please close this thread. it isnt working
What's not working is your description and/or understanding of a transformer.

I get the feeling, you think the secondary is 'floating' because it's a Delta primary.

That set up is common as dirt ....

Slope Organism Rectangle Font Triangle


If what you have is different, then tell us what it is !
 

·
Registered
Residential, lite comm., Industrial
Joined
·
147 Posts
Discussion Starter · #32 ·
What's not working is your description and/or understanding of a transformer.

I get the feeling, you think the secondary is 'floating' because it's a Delta primary.

That set up is common as dirt ....

View attachment 158450

If what you have is different, then tell us what it is !
I dont know what the primary is and it doesn matter, or what the secondary is and I dont care. the secondary has 3 hot wires going to the mill................ no ground............. no neutral........ just 3 hot wires .......... that is it
 

·
Registered
Residential, lite comm., Industrial
Joined
·
147 Posts
Discussion Starter · #33 ·
I dont know what the primary is and it doesn matter, or what the secondary is and I dont care. the secondary has 3 hot wires going to the mill................ no ground............. no neutral........ just 3 hot wires .......... that is it
what is the common trade name for that configuration ?
 

·
Registered
Retired EC and Fuel distribution contractor
Joined
·
1,713 Posts
what is the common trade name for that configuration ?
As far as I know there is no "common trade name for that configuration", probably because it's not so common. I've lived a somewhat sheltered electrical life, but until your post I had never heard of this being done the way you say. I don't doubt you, I just don't believe there is an answer to your question.
 

·
Registered
Residential, lite comm., Industrial
Joined
·
147 Posts
Discussion Starter · #35 ·
As far as I know there is no "common trade name for that configuration", probably because it's not so common. I've lived a somewhat sheltered electrical life, but until your post I had never heard of this being done the way you say. I don't doubt you, I just don't believe there is an answer to your question.
[/
you may well be right. one of the replies i got said they thought it used to be delta secondary, (which makes sense) and the only pots the poco had on hand when it burned up had to be connected wye (not sure why).
however i am currently looking for a post that i saw a day or 2 ago (i had been stalking this site for 3 days before i joined today) and he called a service "floating delta".... if i can find him, i will ask him. i am not exactly well exposed myself, thus the question
 

·
Registered
industrial E,I&C
Joined
·
3,620 Posts
You can have a ungrounded whe as long as no wires on the secondary side are connected to ground. If the secondary is connected to ground what you have is dangerous.
 

·
Registered
Residential, lite comm., Industrial
Joined
·
147 Posts
Discussion Starter · #37 ·
You can have a ungrounded whe as long as no wires on the secondary side are connected to ground. If the secondary is connected to ground what you have is dangerous.
i dont know if the secondary is grounded at the pots. i saw it weeks ago and im working from memory and not looking at much else but the 3 hot wires to the mill
 

·
Registered
Ready Mix concrete plant electrician
Joined
·
2,477 Posts
It is a normal metal building on a concrete slab. standard construction

HOLD UP, no center taps. yes, these are the pole transformers/ POCO xfmrs. 480V 3 phase. the secondary of the pots has ONLY 2 connections. #1 is to the other 2 pots and then ground #2 is to the 3 hot wires to the mill
All right A-R slow down, what is causing some confusion is this small statement about the connections. If the Star center is grounded like you say, then a phase ground at say a motor JB will cause a breaker/fuse to trip.
you are probably correct, i dont know. and there are no alarms or lights as you said. i have already had the call where a motor shorted to ground and the supervisor says "the supply is bad, i get 0V phase to ground." Luckily i remembered there is such an animal at a mill i used to work for : 1 phase to ground, no problem. but fix it before the 2nd phase shorts or you will trip the main
If you have a grounded xformer bank outside, whether it be a grounded phase, or a center tap, or a Star center, and a phase to ground in a motor, you will clear a fuse or a breaker. This is regardless of the fact that you only have 3 phase wires coming into the building. The current will find a path back to the xformer bank one way or another if indeed it's grounded as you say.
 

·
Registered
Residential, lite comm., Industrial
Joined
·
147 Posts
Discussion Starter · #39 ·
All right A-R slow down, what is causing some confusion is this small statement about the connections. If the Star center is grounded like you say, then a phase ground at say a motor JB will cause a breaker/fuse to trip.

If you have a grounded xformer bank outside, whether it be a grounded phase, or a center tap, or a Star center, and a phase to ground in a motor, you will clear a fuse or a breaker. This is regardless of the fact that you only have 3 phase wires coming into the building. The current will find a path back to the xformer bank one way or another if indeed it's grounded as you say.
Agreed. I have already experienced a single phase ground in the system. How or why it works was not the question
 
21 - 40 of 80 Posts
Top