Previous in Forum: ISOLATION OF PT   Next in Forum: Reactors in Power Factor Corrector
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
4 comments
Rate Comments: Nested
Sadanand
Participant

Join Date: Aug 2007
Posts: 1

Single Phase Power Supply

08/18/2009 4:03 AM

i have 415 vac 50 hz supply ( 70 kva) from mains .

i want to make a device which provides 220vac single phase supply

for spot weld m/c ( which may take 100 amp current)using abovesaid input.

how can i do that ?
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#1

Re: single phase supply

08/18/2009 4:28 AM

Phase, neutral and earth. If in doubt, consult a qualified electrician locally.

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
hentoyk
Power-User
Engineering Fields - Electrical Engineering - Hentoyk Philippines - Member - BRUTUS Saudi Arabia - Member - Brutus United Arab Emirates - Member - Brutus

Join Date: Aug 2009
Location: Gulf Region, IIEE_CRCSA
Posts: 113
Good Answers: 2
#2

Re: single phase supply

08/18/2009 7:23 AM

You can not get 220V out of 415V but 240V. If your welding machine nameplate rating voltage range is 220-240V then line to neutral scheme will works(415V divide by sq. root of 3 = 240V in any phase-to-neutral. Suppose your machine rated only or marked 220V, Other option is to use autotransformer (415/380/220)with ample capacity to carry your machine load. Consult your local manufacturer/dealer and electrical engineer/s (if any).

__________________
 If there is a will... there is a way... No pain / No gain.
Register to Reply
Simon Wan
Guru

Join Date: Apr 2007
Posts: 577
Good Answers: 10
#3

Re: Single Phase Power Supply

08/21/2009 8:30 PM

What you can do, is to use a step down transformer to convert from 3 phase to single phase voltage.

So what will be your step down transformer capacity? It a very simple calculation.

You have 415V at 70KVA. …. From your mains

You need single phase 240 at 100 amps…

Your step down transformer will be …..100 Amps x 240V x 1.732 = 41.568 Kva …. So you get a 45KVA or 50KVA step down transformer

Reverse back the calculation to the transformer primary calculation will be ….45KVA/(415/1.732) is only 62.6 KVA from your mains ….. Or….

For 50 KVA will be about 69.56 KVA from your mains.

__________________
 Management is just like a bunch of Monkey sitting on a tall tree. Some climb to the highest branch and some at the lowest branch. The highest Monkey look down and see a lot of happy faces but the lower Monkey looks up and see nothing but all the....
Register to Reply
hentoyk
Power-User
Engineering Fields - Electrical Engineering - Hentoyk Philippines - Member - BRUTUS Saudi Arabia - Member - Brutus United Arab Emirates - Member - Brutus

Join Date: Aug 2009
Location: Gulf Region, IIEE_CRCSA
Posts: 113
Good Answers: 2
#4
In reply to #3

Re: Single Phase Power Supply

08/22/2009 1:42 AM

of course you understand the principle of tranformers... you are really an engineer, because you know how to get single supply out of three phase... congrats!

__________________
 If there is a will... there is a way... No pain / No gain.
Register to Reply
Register to Reply
Have a Different Question?
4 comments
Copy to Clipboard

Users who posted comments:

hentoyk (2); PWSlack (1); Simon Wan (1)

Previous in Forum: ISOLATION OF PT   Next in Forum: Reactors in Power Factor Corrector

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Electrical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (156 right now)
Show Members
Advertisement