[BC] Cyberpower brand UPS

[Gary Peterson]

Even utility power can be nasty, as far as THD is concerned.  At some radio
studios, on the 6th floor, of a ten story building, I once hooked a HP
distortion analyzer to the secondary of a 6.3 V filament transformer.  When
the primary was plugged into a wall outlet, I measured around 10% THD on the
60 Hz AC.  This was in the early 80s, before switching power supplies became
very common.  The elevators used motor-generator sets to provide the DC.  I
used the same transformer to look at the AC with an oscilloscope.  There was
a very noticeable "spike" on the rising waveform, after zero-crossing.  I
never did figure out what was causing this anomaly.  The stations moved to
another location before any PCs, microprocessors or UPSes became part of the
inventory, rendering the measured THD moot.

BTW, I am a chicken.  I wouldn't have the guts to plug the input of a
distortion analyzer or oscilloscope directly into and AC outlet. That's why
I used a filament transformer.  And, while I think of it, I have found
outlets, that were wired by licensed electricians, with the hot and neutral
swapped.

Gary, KØCX     

" Check it out for yourself.  The power company provides power at  
generally under 1% THD, and always under 3%.  It isn't that the power  
company is generating this distortion, but power supplies hung on the  
line are doing it.
--chip "