Re: 220v/50hz power rig

[Kevin Loch <kloch () opnsys com>]

Most UPS's pass line voltage straight through
unless it disappears or goes out of range. It's
more efficient and results in less wear and tear
than running Ac->DC->AC all the time.  You can
usually tell when they are generating power by 
the neat buzzing noises they make.

So they all have an ocsillator for when they need
to generate power, but otherwise 
what goes in is what comes out (voltage and especially
frequency).

A 240V/50Hz ups will probably generate the desired
240V/50Hz signal only when in battery only mode
(or plugged into a 50Hz line source).  Check the
specs to be sure.

KL

Sean Donelan wrote:
> Actually, its not being clever, its being cheap.  If you use
> the input frequency to drive the output frequency, you don't
> need an extra crystal oscillator.  Its cheaper, and results
> in fewer customer service calls about the clock running fast or
> slow.  It also means, you can't just take a 50/Hz european UPS
> and plug it into an US plug at 220vac, and expect to still get
> 50/Hz out of it.  When you plug it into the US grid, you'll get
> 60/Hz out.