[time-nuts] [volt-nuts] Safe power-up. was (Solartron 7075 ...)

ws at Yahoo warrensjmail-one at yahoo.com
Mon Oct 10 18:00:41 EDT 2011


Power factor correction power supplies has not been a BIG problem with my 
OLD recycled equipment.
I tried to Cover that case in my end note,
With switchers, turn the variact to normal and use the other safety features 
and a big enough light bulb to keep from blowing it all up if something is 
wrong.

ws

*****************

Poul-Henning Kamp phk at phk.freebsd.dk

>In message "WarrenS" writes:
>
>I don't plug ANYTHING new to me, directly into the line the first time I 
>try
>it.
>(especially if it had a blown fuse)
>
>Here is the solution that I use for a universal, general purpose, tester 
>for
>Old (and new) equipment.

That procedure is fine for linear power-supplies, but not resonably
modern switch-modes.  In particular, anything that has PFC correction
is not going to respond too well to variable voltage like that.
-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20

***************
>
> I don't plug ANYTHING new to me, directly into the line the first time I 
> try
> it.
> (especially if it had a blown fuse)
>
> Here is the solution that I use for a universal, general purpose, tester 
> for
> Old (and new) equipment.
> This is a great tool that can be used for trouble things that draw too 
> much
> current, has shorts, for reforming caps, Testing line voltage sensitivity
> etc, etc.
>
> First time powered up test equipment is powered from:
>
> 1) A line voltage rate light bulb in series, starting with a low wattage 
> and
> working  your way up.
> The light bulb acts Nonlinear variable dropping resistor, which act like a
> current limit and will limit the max current to a safe value but still 
> have
> minimum effect at lower currents due to it's Hi TC.
>
> 2) The voltage to the Light bulb comes which from adjustable variact.
> The voltage rise and the Time at each voltage setting is a learned 
> function
> and depends on what is being tested.
> If you're in a hurry, set it to the nominal line output and flip the 
> switch.
> The rest of the stuff will still provide protection.
>
> 3) The Variact is plugged into a KillAwatt meter
> Used to constantly monitor the power, If it shows too much power is being
> used, ... Well don't let it do that..
>
> 4) The Kill-a-W is plugged into a solatron 1 to 1 line regulating
> transformer.
> My Line regulating Solitron has the very desirable built in characteristic
> that it goes into a saturation mode that limits the max output power if
> overloaded
> If not overloaded, it outputs a constant voltage.
>
> 5) Have a few resetable and/or  standard  fuses in there to be over safe.
>
> The proper use of the variact's output voltage has a learning curve, 
> because
> equipment with switchers behave differently than things with linearly
> supplies
>
> ws
>
> *****************





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