The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Forum Software Upgrade coming soon...
by Ruben Rocha
9 minutes 41 seconds ago
ESA Arc flash course
by frank
38 minutes 45 seconds ago
Re: Fabricating Guards out of Lexan?
by frank
Yesterday at 04:11 PM
Would ELV branch circuits be a good idea?
by gfretwell
Yesterday at 01:26 PM
Why cables look like they do
by Texas_Ranger
Yesterday at 12:33 PM
New in the Gallery:
Desk-mounted "power-board"
Top Posters (30 Days)
HotLine1 21
Webmaster 20
Trumpy 12
ghost307 12
frank 12
Who's Online
3 registered (Webmaster, Ruben Rocha, sparkyinak), 0 Guests and 197 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#134914 - 12/06/02 07:10 PM How do I do it Safely?
electure Offline


Member

Registered: 12/24/00
Posts: 4229
Loc: Fullerton, CA USA
I work with a couple of manufacturing companies that have home bases out of the US.
We've added 480x380,etc. transformers and odd buck/boost transformers (autotransformers) to spots as needed for the occasional odd voltage (here 277/480Y, 120/208Y are our nominal voltages).
I now have been "elected" to find a way to supply 100 volt power.
Does anyone have a source for this?
I only need about 30KVA, but I'm at a loss for the 100v 60Hz power, as the transformer doesn't seem to be available here in the US, and the manufacturer, in Japan, hasn't responded.
Thanks..S


[This message has been edited by electure (edited 12-07-2002).]

Top
Test Equipment:

Large Selection of Test Equipment For Electrical, HVAC, Test & Measurement
Large Selection of Test Equipment For Electrical, HVAC, Test & Measurement

#134915 - 12/06/02 09:36 PM Re: How do I do it Safely?
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
Must the 100 volts be one 2-wire circuit? At 30kVA, that is 300 amperes. Safely designed maybe, but not cheaply.

Could the 100-volt load be split into 3 parts? That could reduce material costs some.

What is the acceptable voltage range for the nominal 100-volt equipment? Is a ~104-volt nominal acceptable?





[This message has been edited by Bjarney (edited 12-07-2002).]

Top
#134916 - 12/11/02 04:22 PM Re: How do I do it Safely?
electure Offline


Member

Registered: 12/24/00
Posts: 4229
Loc: Fullerton, CA USA
Yes, Bjarney, a voltage of 104 is acceptable, and a 3Ø system would be fine!
The circuits will be be used for industrial process equipment. We're supposed to install a few of the branch circuits now, and the bulk of the capacity is to be used for future expansion. (I've not even seenany of the equipment.)

[This message has been edited by electure (edited 12-11-2002).]

Top
#134917 - 12/11/02 10:17 PM Re: How do I do it Safely?
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
At http://www.federalpacific.com/literature/drytrans/FPTS-RTB-0701.pdf page 12, you could possibly use a 120:16V 5kVA {SB16N5F} transformer. that would buck 120V to 104V at 313 amperes. Else, if the “30kVA” feed was 4-wire wye, you could use three 2kVA {SB16N2F} transformers, each connected on a per-phase basis.

For 2-wire 120-to-104 volts connect 120V and 104V neutrals paralleled to H2/H4, with the 120V “hot” to H1/H3 and X1/X3, and 104V “hot” to X2/X4.

Use one 2kVA transformer for each 208Y/120V phase terminal.

Top
#134918 - 12/20/02 07:07 PM Re: How do I do it Safely?
electure Offline


Member

Registered: 12/24/00
Posts: 4229
Loc: Fullerton, CA USA
Bjarney,
Thanks! I hadn't even thought about bucking this one down with autotransformers. Now they'll have their 104/180Y panel.
Now what colors am I going to use for that one? (Only kidding, but heck I've about run out!)
Thx...S




[This message has been edited by electure (edited 12-20-2002).]

Top
#134919 - 12/20/02 08:13 PM Re: How do I do it Safely?
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
Been thinking about phase colors...how about puce, salmon and burnt sienna with a putty neutral?

Top


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals