# Transformer design?

Discussion in 'General Electronics Chat' started by Jaybee55, Jan 16, 2013.

1. ### Jaybee55 Thread Starter New Member

Jan 16, 2013
2
0
Hi guys,

ASCII art example

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240v is the AC mains supply. 35A max

I know that the AC adapter will have a voltage drop(I * R), which will reduce the voltage supplied to the load. How can I design this connection/the adapters in a way which will result in the minimum voltage drop across the adapters but yet able to squeeze enough power from it?

2. ### crutschow Expert

Mar 14, 2008
13,501
3,375
You question is confusing. What output voltage and current do you need?

What do you mean "minimum voltage drop across the adapters"? Do you mean minimum power loss?

3. ### ScottWang Moderator

Aug 23, 2012
4,933
777
About the adapters, adapter is convertor, whatever it is a dc-dc or ac-dc, they always has the conversion efficiency problems..

Assuming:
Input watt : W_in = 240V * I_in
conversion efficiency : 90% (lost 10% energy)
Back up for plenty current : 10~30%
Output watt W_out = 24V * 35A = 840W
W_out = W_in * 90% * (1+30%)
W_out = 240V * I_in * 90% * (1+30%)
You can calculate the I_in by your own.

4. ### Jaybee55 Thread Starter New Member

Jan 16, 2013
2
0
Sorry for the unclear post.

Here a picture of what i am trying to implement.

Current circuit:

What I hope to implement:

Legend:
Single phase AC
Yellow = Live AC
Blue = Neutral AC
Red = +15v
Black = gnd

I have never deal with adding anything in series to a load, how will it affect the circuit? What kind of device/transformer should i be using to minimize the effect of the additional circuit?