[Amps] Step-start Calculation Problem:

[R.Measures]

On Nov 20, 2004, at 6:50 AM, Bill Turner wrote:

> 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)
>
> _________________________________________________________
>
> 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.
>
The filter stores c. 4500J @9900v.
> --
> Bill W6WRT
>
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org