[Amps] Step-start Calculation Problem:

[Bill Turner]

On Fri, 19 Nov 2004 09:42:43 -0800, R.Measures wrote:

>Question:  A Hipersil transformer with a combined primary+secondary 
>winding ESR of 0.144?,, is connected to a FW rectifier/C-filter.  If 
>the transformer is connected to 240Vrms mains with  an ESR of 0.127?, 
>what is the maximum peak inrush current?  What would be a suitable 
>value of step-start R to limit the inrush current to 50A-rms?   (--  
>note -- assume that the Hipersil transformer has virtually zero core 
>loss)

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There is another factor which must be considered: The amount of
capacitance at the output of the full wave rectifier.  The
transformer/rectifier will try to charge it to full voltage in the
first half-cycle and that will cause the greatest part of the inrush
current.

--
Bill W6WRT