# 3 phase AC output transformer 30 degrees to 120 degrees how?

Discussion in 'General Electronics Discussion' started by Danny Daviss, Mar 17, 2013.

1. ### Danny Daviss

67
0
Mar 16, 2013
The 3 Phases are 30 degrees apart before the output transformer

The output transformer turns 30 degrees into 120 degrees AC, but how does it do this please?

Its for 3 Phase UPS systems

2. ### Harald KappModeratorModerator

11,533
2,656
Nov 17, 2011
What circuit are you talking about?
How do you know these pahse differences? Did you measure them? Where do they come from?

I very much doubt that what you describe really happens. A transformer can rotate the phase from input to output. However, it will do so for all phases in the same way. Therefore, signals that are 30° apart on the input side of the transformer will still be 30° apart on the output side - even if they are 180° phase shifted between input and output.

3. ### Danny Daviss

67
0
Mar 16, 2013
Its a UPS 3 phase system

The phase difference are 30 degrees apart before the output transformer

Yes I understand that too

4. ### Danny Daviss

67
0
Mar 16, 2013
Its 3 phase , 120 AC , 120 degrees is the output of the unit

When you measure with an oscilloscope before the output transformer the 3 phase waveforms on a 3 channel oscilloscope are 30 degrees apart. When measuring the 3 phases after the output transformer, the 3 phase are 120 degrees apart.

How does that work?