Re: ups installation question

"w_tom" <w_tom1@xxxxxxxxxxx> wrote in message
news:432A21B4.8E312FCE@xxxxxxxxxxxxxx
> The restart of equipment after a blackout does not create a
> voltage surge. It creates a heavy load on generator (current
> surge) which means electronic appliances power up slowly. It
> means electric consumers see voltage slowly rise. Electronics
> prefer a slow power up which is why we install a current
> inrush limiter inside electronics; so power-on is slower just
> like power restoration from a blackout.

I assume this is addressed to me. I was not clear in my statement,
please allow me to elaborate. I was refering not to the user end restart,
but with the power suppliers end. The standard operating proceedures for
most small generators that I am aware of (60 Kw and less) require that all
circuits be dropped at the generator and then the equiptment be restarted.
After a short warm up the engine has stablized, the generator is engaged and
then circuits are brought back online one at a time and with each the
generator load is managed and stablized. This is a best practices sequence.
If however this is not done, the restart can produce wide power fluctuations
and unless interveining measures have been taken can send spikes down the
line that are harmful to end user hardware.

> Meanwhile powerup from a blackout is harmful to devices that
> don't like slow power up such as electric motors. Power up is
> not harmful to electronics but can stress electric motors.

True, but then most such items are more robust and and as such suffer
little harm. Low voltage in electronic devices can create excess heat which
over a long persiod of time could cause damage.

> Many assume damage was created by a 'power on' surge rather
> than first learn about a destructive transient that created
> the blackout. A transient that would pass unimpeded through a
> plug-in UPS. This problem is why 'whole house' protectors are
> installed; a solution beyond the scope of this discussion.
>
> Kevin Childers wrote:
> > "w_tom" <w_tom1@xxxxxxxxxxx> wrote in message
> > news:432A0E74.46BC1B5B@xxxxxxxxxxxxxx
> >> 2C) UPS is only for data protection - not hardware
> >> protection. Power failures don't cause hardware damage -
> >> except in myths and speculation.
> >
> > As far as I know, the germ of truth in this might come
> > from systems run on small local power grids where small
> > outages are followed by a sudden restart of equiptment that
> > can create a surge.
> > ...


.

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