Re: [CAD_CAM_EDM_DRO] Re: Power supply softstarts

Dave,

I was having a problem with a hard-start -- whenever the computer commanded
the power supply to turn on, it would blow the circuit breaker. Since the
computer was on the same circuit, it was a suicide circuit.

I resolved the problem by changing the capacitors through a 10 ohm
resistor, and shorting out the resistor shortly (a few power cycles) after
powering the transformer.

-- Carl


At 05:39 PM 4/4/2005, you wrote:

> >
> > http://www.thermometrics.com/assets/images/cl.pdf
> >
> > To test this out, you can just rob a bunch out of some old computer
>power
> > supplies, paralleling them (most likely) until you get what you
>want.
> >
>
>Another addition is a potential relay. Many air conditioners have a
>potential relay so as to allow the compressor to use a starting
>capacitor. once the realy gets to something like 80% of line voltage,
>it then changes state and you get across the line voltage.
>
>The problem with thermistors is they have different resistances
>depending on the chip temperature. for a brown-out, they would not
>properly protect the circuit although at such time the caps would be
>at least partially charged.
>
>Another option, and one I'm only tossing out as an idea, is to use
>some sort of semi-conductor and just PWM it until it reaches some
>high percentage of the expected power supply voltage.
>
>Dave