Re: Power supply softstarts

It needs to be a box that just gets turned on. I don't want knobs
to turn and the associated weight.

The fact I am using servos has nothing to do with it, the softstart
is for the inrush on the primary of the transformer.

For the record I am in the UK on 240v

Graham




--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@y...>
wrote:

> How about a 110volt 10 amp variac on the primary? Strat the power

supply at a low setting then gradually increase it. They can be had
pretty inexpensively. With servos, I dont think this is an issue.

>
> Ron
>
> Graham Stabler <eexgs@n...> wrote:
>
>
>
> I am building a 6 axis system with linear servo motors and have
> bought a pair of 500VA transformers which should provide 50v and
> sufficient amps for peak acceleration. I have also got a 100,000uF
> capacitor for smoothing although I may increase this.
>
> On my previous homebrew power supply I added a softstart that
> charged the output capacitors via a resister until they were up to
> voltage. The prevents a nasty thud on turning on the supply.
> However I have a feeling that with the two transformers in this
> supply in parallel I may have more of a problem with the

transformer

> inrush current which does more than make a thud!
>
> What is the "best" way to produce a soft start on the primary of

my

> powersupply. Should I just use a contactor, timer and power
> resister to provide a current limited supply to the transformer on
> power up?
>
> Thanks in advance for any help
>
> Graham
>
>
>
>
>
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