Author Topic: Transformer - Dual Primary Parallel connection  (Read 1449 times)

0 Members and 1 Guest are viewing this topic.

Offline anishkgtTopic starter

  • Frequent Contributor
  • **
  • Posts: 769
  • Country: qa
    • George Hobby
Transformer - Dual Primary Parallel connection
« on: December 06, 2016, 09:40:45 pm »
Just ordered one of these PCB Transformer from Block
http://www.farnell.com/datasheets/1821919.pdf?_ga=1.149693054.998134959.1479939742

Is it required to connect the dual primary pins in parallel when using 120VAC ? I can see TRIAD suggests to do so. What are the advantages and disadvantage of doing so ?

My schematic is here, I was plaing to using jumpers to choose between 115 & 230VAC.
 

Offline helius

  • Super Contributor
  • ***
  • Posts: 3632
  • Country: us
Re: Transformer - Dual Primary Parallel connection
« Reply #1 on: December 06, 2016, 09:59:06 pm »
The advantage to it is that the transformer can handle as much power with 120V as with 240V, by drawing twice the primary current. This is limited by core saturation, of course, but a dual-voltage transformer should be designed to handle it.
The disadvantages are the more complicated voltage switch arrangement required, and the risk that the primaries could get wired with incorrect phasing.
 

Offline anishkgtTopic starter

  • Frequent Contributor
  • **
  • Posts: 769
  • Country: qa
    • George Hobby
Re: Transformer - Dual Primary Parallel connection
« Reply #2 on: December 06, 2016, 10:05:24 pm »
Wanted to know if the wiring correct. The block brand  does not have it mentioned l so a bit confused.


Sent from my iPhone using Tapatalk
 

Offline Benta

  • Super Contributor
  • ***
  • Posts: 5840
  • Country: de
Re: Transformer - Dual Primary Parallel connection
« Reply #3 on: December 06, 2016, 10:36:59 pm »
If the transformer "polarity dots" on your schematic are right, then your wiring of the primaries is correct.

Transformers nowadays are highly optimized with regards to copper and iron content.
The reason for wiring the primaries in parallel at 120 V is to reduce copper losses due to resistance (=heat) when the transformer is fully loaded.

Saturation current has nothing to do with this.

 

Offline Seekonk

  • Super Contributor
  • ***
  • Posts: 1938
  • Country: us
Re: Transformer - Dual Primary Parallel connection
« Reply #4 on: December 06, 2016, 10:51:23 pm »
You can use a small wattage lamp in series with primary power for your first.  If you wired either the primary or secondary out of phase, it will save your transformer.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf