3 phase transformer single phase supply - Page 2 - Electrician Talk - Professional Electrical Contractors Forum
 Electrician Talk - Professional Electrical Contractors Forum 3 phase transformer single phase supply
 Register Articles Rewards Search Today's Posts Mark Forums Read

06-12-2016, 10:28 AM   #21
Band Member

Join Date: Mar 2015
Location: Eastern Ontario
Posts: 6,140
Rewards Points: 1,860

Quote:
 Originally Posted by Ultrafault My boss asked me a question, and I could not satisfactorily explain what would happen if you hooked a three phase transformer to a single phase supply. For the sake of this conversation we assumed the transformer would be delta 240 to wye 480 as the suggestion was for step up. I told him it would be horribly inefficent but to be honest I was only using supposition. Could some of you guys enlighten me about the physics of this situation? Could you use this setup as a single phase transformer? What output could you expect at the secondary conductors? Would a delta delta transformer provide you with different results?
If you connected 240V to H1 H3 , you would need to ground H2
The result on Wye or Delta would be the same, because the vectors are 180˚ apart. You would have 480V on X2 to X0 , and 240 on both X1 and X3 to X0
Although in Delta secondary you would have 480V on X1 to X3 and 240V on X2 to X1 and X3

Made a quick drawing to show it better.

The thing to remember is that the "wye" output is NOT a Y ... ie they are not 120˚ vectors, so they simply add up.

**edit** added dwg ... note, two H1's on primary ... one should be H3
Attached Thumbnails

__________________
_____________________________________
Your Mother was a hamster, and your father smells of Elderberries. ... Now go away, or I shall taunt you a second time
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by emtnut; 06-12-2016 at 10:34 AM.

 Join the #1 Electrician Forum Today - It's Totally Free! ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

 Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

06-12-2016, 12:10 PM   #22
Senior Member

Join Date: Oct 2012
Location: Alberta Rockies
Posts: 2,789
Rewards Points: 3,932

Quote:
 Originally Posted by emtnut If you connected 240V to H1 H3 , you would need to ground H2 The result on Wye or Delta would be the same, because the vectors are 180˚ apart. You would have 480V on X2 to X0 , and 240 on both X1 and X3 to X0 Although in Delta secondary you would have 480V on X1 to X3 and 240V on X2 to X1 and X3 Made a quick drawing to show it better. The thing to remember is that the "wye" output is NOT a Y ... ie they are not 120˚ vectors, so they simply add up. **edit** added dwg ... note, two H1's on primary ... one should be H3
Since it is a step up transformer, wouldn't the 240 vac go onto X1 and X3, and the 480 would be on the high side?
This might do in a bind, but I'm thinking the correct transformer should be installed as soon as possible....

06-12-2016, 12:18 PM   #23
Band Member

Join Date: Mar 2015
Location: Eastern Ontario
Posts: 6,140
Rewards Points: 1,860

Quote:
 Originally Posted by glen1971 Since it is a step up transformer, wouldn't the 240 vac go onto X1 and X3, and the 480 would be on the high side? This might do in a bind, but I'm thinking the correct transformer should be installed as soon as possible....

Yes, it should ! I was still on my first coffee
__________________
_____________________________________
Your Mother was a hamster, and your father smells of Elderberries. ... Now go away, or I shall taunt you a second time
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

06-12-2016, 12:35 PM   #24
Bilge Rat

Join Date: Aug 2007
Posts: 6,722
Rewards Points: 3,052

Quote:
 Originally Posted by emtnut If you connected 240V to H1 H3 , you would need to ground H2 The result on Wye or Delta would be the same, because the vectors are 180˚ apart. You would have 480V on X2 to X0 , and 240 on both X1 and X3 to X0 Although in Delta secondary you would have 480V on X1 to X3 and 240V on X2 to X1 and X3 Made a quick drawing to show it better. The thing to remember is that the "wye" output is NOT a Y ... ie they are not 120˚ vectors, so they simply add up. **edit** added dwg ... note, two H1's on primary ... one should be H3
The X windings on a 240∆ - 277/480Y transformer are 277 volts, not 480. 480 is derived from the Y connected 277 volt windings having 120º of phase shift.

06-12-2016, 12:47 PM   #25
Band Member

Join Date: Mar 2015
Location: Eastern Ontario
Posts: 6,140
Rewards Points: 1,860

Quote:
 Originally Posted by micromind The X windings on a 240∆ - 277/480Y transformer are 277 volts, not 480. 480 is derived from the Y connected 277 volt windings having 120º of phase shift.
Yep !

So you would have 277V , and 138.5V for that tx .... think that's what you said in your earlier post
__________________
_____________________________________
Your Mother was a hamster, and your father smells of Elderberries. ... Now go away, or I shall taunt you a second time
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

 The Following User Says Thank You to emtnut For This Useful Post: micromind (06-12-2016)

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post mr_electrician Services and Service Equipment 4 05-25-2016 06:29 AM te12co2w PLCs, VFDs, Motors and Controls 62 03-14-2016 11:47 AM TechieBecky Canadian Electrical Forum 16 02-19-2016 04:46 AM CEC09 Canadian Electrical Forum 3 02-10-2016 03:35 AM just the cowboy General Electrical Discussion 2 01-21-2016 11:36 AM

All times are GMT -4. The time now is 07:51 PM.