I need to find a voltage transformer 100/110 Volts 30VA. Does anyone knows any manufacturer for this kind of transformers?

 

Responding to G. Laloumis' Feb 16, 11:57pm query... almost any transformer having a 10:1 pri/sec ratio can be used!

1) As an example, a 120V/12V filament transformer could be used! (An aside for those who don't know... at one time TV electronics consisted
of electron tube or valves.)

2) Call the primary winding ends A-B and the secondary winding ends C-D. Connect B to C. Then apply 100V between A-B. If the voltage measured
between A-D is 110V the winding voltages are said to be "additive!"

3) If the voltage measures 90V the winding voltages are said to be "subtractive!" Then, simply connect B to D.

4) Now caveat #1.
The above should not be used unless the primary and secondary winding insulation are suitable for the resultant voltage to ground (earth)!

5) Caveat #2.
Because of leakage effects there will be a slight difference between the theoretical voltage-ratio, and the transformer's turns-ratio.

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])

 

Two additional comments to my response to G. Laloumis' query... the configuration is like an autotransformer having positive and negative
features:

6) The transformer's capacity need only be about 3 VA.

7) The primary and secondary circuits are not isolated.

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])

 

These two transformers will be used as interposing transformers and they will be connected to a resistor of 1000 ohm and an input of a "PLC" in parallel. They wiil be used for the synchronization of a power unit to a national power net. I believe this changes a little the results.

 

Responding to Anonymous' Feb 21, 11:37pm comments:

Obviously you know more about the original query than was described. Please clarify.

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])