230/460 Open Delta
- Thread starter Npstewart
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electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Whether a delta system is derived from an open or closed delta has nothing to do with how or if the system is grounded or the arrangement of a neutral. An open delta uses two transformers instead of three. A high leg has a center tap on one of the transformers which is what you have but again it could be open or closed. I have never run into a high leg 480 system.
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
You've got it right. Yes, pretty rare and even more rare for a PoCo to supply a new a new one. I've had a few over the years and oddly enough, I just encountered one the other day.
The conventional notation would be 480/240V 3? 4W and perhaps append Open Delta where indicating transformer configuration.
PS: Is anyone else having problems with editing their post. In IE and Chrome I edit my post and click Save Changes. The litter spinner shows, but nothing else happens. I've been having to click Go Advanced to save changes. Currently I'm attempting to change the ? after 3 to the phase character. I was pretty sure I put in the proper character on initial post... but now no matter what I try I can't change it to "?" in Chrome...
PPS: Apparently it's not working in Chrome either. Chrome is currently sitting there with the spinner rotating in advanced mode even though the post actually went through (without correcting either phase symbol).
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mivey
Senior Member
Well of course there is. The nominal is different.
For example from http://www.portlandgeneral.com/business/builders_developers/docs/Services.pdf
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mivey
Senior Member
Yes. Very irritating. Also a lot of old posts have lost things like degree symbols.
Also your post disappears after a preview. What a pain!!!:rant:
Ditto for that and other symbols. I hate it.:rant:
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
Thanks for the heads up. Next time on a job with one I'll remind the crew that this is virtual and really does not exist.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
The bigger question is, do you NEED some small amount of 240V single phase for something? Keep in mind, this will NOT be 120/240V single phase, it is ONLY 240V from phase to neutral. That means your 240V load will not be connected line-to-line, but line-to-grounded neutral, and if anything else inside of it is assuming line to neutral will be 120V, it will fry.
In my opinion its going to be oddball enough to cause some future electrician, i.e. one who believes it doesn't exist, to make some sort of disastrous mistake.
In my opinion its going to be oddball enough to cause some future electrician, i.e. one who believes it doesn't exist, to make some sort of disastrous mistake.
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I hate to burst everyone's bubble but I found out this morning that the voltage to the building is actually 240-3 open delta, not 480/240, the electrician made a mistake. The rep from the power company says that this voltage does exist but he said you will not find that in FP&L territory anywhere. FP&L is the poco company for most of Florida.
Also, I have one 240v-3 phase load, and I had a hard time wrapping my head around that this couldnt be serviced with a phase to phase connection. I wonder if this could be connected with the neutral and a phase?
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Either you are saying something incorrectly here, or you should leave this to professionals. Phase to neutral would be SINGLE phase, not 3phase.
I meant 240-1. Sorry for the confusion in your presence.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Ok, didn't mean to offend, but realize that this is a site FOR electricians, not to be used IN LIEU of electricians.
If you really do have a 240V open delta service, there is no neutral. So there is no valid phase-to-neutral voltage, it would float and may go very high, damaging your equipment. Your voltage phase-to-phase is 240V, that's what you would use.
- Location
- Connecticut
- Occupation
- Engineer
No offense, but according the forum FAQs,
This site is designed for:
- Contractors
- Electricians
- Engineers
- Inspectors
- Instructors
- Other electrically related individuals
This thread was started under the conditions that the voltage was 480-3 delta, not 240-3. It wasnt until this morning that I found out it was 240-3. So my original question which you responded to was more theoretical, if the voltage was actually 480-3, delta, how would you hook up the 240-1 load. I am visiting this forum while I am at work so between the hours of 8-5 on weekdays, I dont always have the luxury of thinking everything through prior to posting.
Not sure how you think I am using this forum "in lieu of" electricians. I find that when people say "I didnt mean to be _______....", that they actually did mean to be what ever goes in the blank.
None of the above requires an additional response.
Not sure how you think I am using this forum "in lieu of" electricians. I find that when people say "I didnt mean to be _______....", that they actually did mean to be what ever goes in the blank.
None of the above requires an additional response.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
I know what you mean. In my experience, when someone starts a remark off with something like "I don't mean to sound racist..." it's usually followed something extremely racist.
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