Primary windings voltage

Thread Starter

Drmario5237

Joined Oct 14, 2018
65
Hello on a transformer if you have two different sources of voltage feeding the primary coil does those voltages add up since it's in series and not parallel. Same with ampage. Does the amps add up or if you feed two different voltage/amprages into the primary coil does it short out. Thanks
 

MaxHeadRoom

Joined Jul 18, 2013
28,702
The (k)Va rating of the transformer stays the same.
When connecting primary (or secondary) winding's series or parallel, they have to be phased correctly, Especially if in parallel.!
Max.
 

drc_567

Joined Dec 29, 2008
1,156
... not completely understanding your question .... a sketch or graphic would help.
... Related ... Say you want to arrange two transformers side by side where the primary windings are hooked up in parallel, each one going to to a mains connection, and then the secondary windings are in series, so as to yield increased, additive, output voltage. The catch is that the larger power transformers have a winding polarity, so that the series connection on the secondary winding may be additive, as planned, but could also be subtractive, giving a decreased total voltage. The way to be sure is to remove any secondary load and use a voltmeter to verify that the total secondary voltage is additive. If the sum voltage is not what it should be then reverse the secondary connection of one of the transformers and test again.
... The transformer polarity is only a consideration on large VI rated transformers. It seems that the small hobby-use transformers have something called bi-filar winding and are not distinguished with the polarity characteristic.
 
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