We have ordered a 6 KVA Liebert UPS for an Inova
600 that we have on order. The Liebert rep asked for
the load specs. When I informed him that Varian specs the
Inova console at a 0.925 LEADING power factor(*) he nearly
freaked. He had never seen a load with a leading power factor,
and was uncomfortable because the inverter on the UPS is
designed for a 0.7 to 1.0 lagging power factor, typical of
an inductive load. A leading power factor is typical of a capacitive
load, likely the result of conventional linear (non-switching) power supplies
in the Inova console. Since linear power supplies are still the standard
in much high-end electronic equipment, I would think the UPS manufacturers
would allow for this.
The question is, has anyone noticed problems with a Liebert (or other) UPS
resulting from a leading power factor?
Thanks in advance
-Kirk
* power factor is the cosine of the phase angle between the current
and voltage in an AC circuit
Kirk Marat, Ph. D., NMR Facility Manager
Dept. of Chemistry
University of Manitoba
Winnipeg, MB, R3T 2N2, CANADA
ph. (204) 474-6259 FAX: (204) 474-7608
kirk_marat_at_umanitoba.ca
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Received on Wed Nov 13 2002 - 17:29:37 MST