creating 3 phase from 2 xfmers

[padyakbud]

I just had a talk with an old excellent electrical engineering friend.  He just came from a job in the province and was perplexed on what he saw.  He saw a small generating plant producing 3 phase power from 2 phases.  What was explained to him was that one of the transformers was bad and will be repaired in the next coming weeks but temporary they were producing somehow 3 phase power from the remaining 2 working transformers.

The question is how is this possible?  As far as I know, you cannot magically create a revolving phase shifting voltage/current from just 2 phases.  And you need the revolving phase to drive 3 phase motors.  Any explanation or is there any new technology or theory that would make this possible?  Links to any reading material is highly appreciated.

Thanks in advance,

Perplexed Bud

[graSS]

That is what you call the OPEN-DELTA CONNECTION...     


Open Delta Connection:
The open delta transformer connection can be made with only two transformers instead of three . This connection is often used when the amount of three phase power needed is not excessive, such as a small business. It should be noted that the output power of an open delta connection is only 87% of the rated power of the two transformers. For example, assume two transformers, each having a capacity of 25 kVA, are connected in an open delta connection. The total output power of this connection is 43.5 kVA (50 kVA x 0.87 = 43.5 kVA).



Ito ang advantage minsan ng delta connection kasi pwde pa rin makapagoutput ng 3phase kng sakaling masira ang isang trnasformer but w/ less power output.            You can Google for more...

[brian_po]

ito yung conection ng open delta.. using 2 transformer..


connect mo lng yung 2[primary] tapos yung 2[secondary]

minsan ko na din nagamit to nung ng paandar ako ng chiller na 3phase 110V 60Hz

[padyakbud]

To Brian_po & graSS Ü,

Thank you for the information!  I will research more on it ... 

[ty-rap]

ito yung conection ng open delta.. using 2 transformer..


connect mo lng yung 2[primary] tapos yung 2[secondary]

minsan ko na din nagamit to nung ng paandar ako ng chiller na 3phase 110V 60Hz

     tama ang connection ni brian....yan ang open delta conn.   derecho ang isang linya sa LOAD...kahit na anong voltahe pa meron ito...

[graSS]

To Brian_po & graSS Ü,

Thank you for the information!  I will research more on it ... 

your welcome po! dami pa yan sa net egoogle mo lng... kng gus2 mo makita sa actual application hanap ka ng poste na may dalawang transformer na magkatabi.. Pwde mo edrawing ang connection nyan. Usually open delta connection yan pag magkatabi.     

[brian_po]

To Brian_po & graSS Ü,

Thank you for the information!  I will research more on it ... 

k lng pow..

meron pa iba jan.. delta to delta or delta to wye.. depends sa pag gagamitan!!
tama si sir grass i tanong mo nlng kay uncle google dami info..

[tony v.]

may problem sa open delta dahil ang load ay hindi balanse kaya minsan ang output voltage ay unbalanced din... practical lang ito kung ang load mo ay specific lang sa isang machine at hindi pabago-bago ang current... ok din ito dahil imbes na tatlong transformer dalawa na lang ang ikakabit ng electric company to save money.

[luis]

Open Delta-this connetion can be used in an emergency in case one of the transformers in a delta-delta bank fails.

[link_toyou]

Hi to All,

   Tanong po ako kasi wala me idea regarding delta connection,. kung unstable po ang output po nito, pwede po kaya shang eh regulate..thanks

[moklo]

ito yung conection ng open delta.. using 2 transformer..


connect mo lng yung 2[primary] tapos yung 2[secondary]

minsan ko na din nagamit to nung ng paandar ako ng chiller na 3phase 110V 60Hz

You can not use this open delta conn when you drive a 3 phase motor. Unbalance kasi voltage niya. \

Let say Line to Line Voltage = 10V

So.

L1-L2 = 10V
L2-L3 = 10V
L3-L1 = 20V