loss of phase... what if question

[Electric-Light]

Of course I mean you line up the direction of rotation and ensure both sides are in phase when directly paralleled.

The question is if you then slip in a 1:1 transformer in between the generators. The transformer introduces a slight phase shift, doesn't it? Would that then cause it to "bind" ?

 

[GoldDigger]

Of course I mean you line up the direction of rotation and ensure both sides are in phase when directly paralleled.

The question is if you then slip in a 1:1 transformer in between the generators. The transformer introduces a slight phase shift, doesn't it? Would that then cause it to "bind" ?

A single phase transformer will not introduce any phase shift in the resistive component of the current (which is all that matters). A three phase transformer that is wye-wye or delta-delta and does not include odd features like zig-zag windings will not introduce any phase shift either.
The magnetizing current will be supplied equally by the two alternators.

 

[Electric-Light]

A single phase transformer will not introduce any phase shift in the resistive component of the current (which is all that matters). A three phase transformer that is wye-wye or delta-delta and does not include odd features like zig-zag windings will not introduce any phase shift either.
The magnetizing current will be supplied equally by the two alternators.

Fine then... let's do 1:1 delta-wye transformer

 

[Phil Corso]

Electric Light...

Caveat:

DON'T DO IT!

Phil

 

[winnie]

Fine then... let's do 1:1 delta-wye transformer

In that case, I think you would introduce a problem

The two sides of this transformer would necessarily have a minimum of a 30 degree phase difference. If your alternators were synchronized without the transformer, then they would not be synchronized as connected _through_ the transformer.

My guess (it would depend on the specifics of the machines being connected) is that this phase difference is small enough that the system would run, but large enough that you would see large curents circulating between the two alternators, and that one alternator would act as a motor driving the shaft, and the other would act as a heavily loaded generator.

-Jon

 

[mivey]

You would need to be careful about the phase rotation; one will be spinning clockwise and the other counterclockwise. Which means that you can't simply connect (directly or via a transformer) phase A to A, B to B and C to C. You would need to adjust the phase angle, and swap a pair of phases. But if everything is aligned, excitation adjusted, etc., then you should be able to parallel the two alternators.

-Jon

Lot of ifs. Those ifs keep the synch gear folks in business. I suspect the heat would get the better of this setup.

 

[mivey]

I don't have to look it up. I already know how phase angle displacements are depicted.

OK. Wasn't sure you were familiar with clock diagrams and such with they way you said AN wasn't used and that the primary side wasn't generally the reference. I guess you meant that in a different light. Pardon the interruption. Carry on.