How many Amp do I need for the transformer

[FLlearner]

Greeting to the forum,

I had ask to design the power supplied for a system. I have 480VAC input and 24VDC output transformer for all instruments such as motors, VFDs,E-stop, Photoeye's.....My question is how much Current(Amp) do I need for the transformer to disconnect the system? Any input would appriciated.

 

[Skogsgurra]

Not an easy question.

First. What do you mean by "disconnect the system"?

Second. We cannot guess how many of all these devices you have or what their supply needs are. No, we cannot. Really. Most of us are not that smart.

Third. Once you got all those data collected. Then you also have an answer to your question.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[FLlearner]

ok So I have to know how much current draw by each divice, the total devices? Then I would know the total current to supply the system?

 

[Skogsgurra]

Yes. And perhaps add some safety margin, too.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[itsmoked]

And remember transformers don't put out DC.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[rsteves]

Transformers convert AC to AC. They are quite efficient so typical calculations assume power in = power out.
In other words: Volts_in*Amps_in = Volts_out*Amps_out.
Rearranging gives: Amps_in = Amps_out*Volts_out/Volts_in

Assuming your output is 24V AC (not DC), once you determine the total current your equipment will draw (Amps_out), multiply that by 24/480 to get the current required to the input side of the transformer. And as Skogsgurra said, add a safety margin.

Rob Steves - Zaber Technologies Inc -

http://www.zaber.com

 

[itsmoked]

If you really want DC then find an appropriate Power Supply switcher or otherwise and then size your transformer to run it.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com