[sdiy] transformer question

[epeasant at telusplanet.net]

>just a thought:
>
>wouldn't be usefull a circuit where transformer is powered up via, say, 1k

>resistors in series with primary windings, and with the load disconnected on

>secondary side, so only rectifier and capacitors are connected. When
>capacitors get charged to full working voltage, a relay shorts those 1k
>resistors and connects the load to the power supply.
>Have anybody tried this?
>
I have seen this used in a number of industrial power supplies, it is called
step-start here. The load is always connected but there are resistors to limit
the inrush current that are shorted out with a contactor after about 1/2 a second.


When I designed a DC motor power supply once I had peaks of over 100 amps inrush
on a 1 amp supply, a step start circuit cured this very nicely.

Take care,
Doug

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The Electronic Peasant

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