AVR (boost/trim) differences between UPS models

[marting]

Hi all,

We have various models of APC UPSes deployed at one of our sites and I'm seeing an interesting difference in the performance of the Automatic Voltage Regulation functionality between different line-interactive UPS models.

Last night - due to an increase in voltage from the utility, we had multiple UPSes kick into AVR mode (Event message: "UPS: Compensating for a high input voltage.").

While in this state:

• On a Smart-UPS 750, the output voltage dropped to ~ 110 - 112.5V
• On a Smart-UPS 3000 X, the output voltage stayed at 119.9 - 120V the whole time

Looking at the event logs on the UPSes, it doesn't look like either of them kicked over to battery so I'm assuming the AVR feature is trimming the voltage.

Question: both of these UPSes list AVR as a feature but the performance is significantly different.  Is there a way to tell from spec sheets, etc. what level of AVR exists on any given UPS model?

[Teken]

Generally speaking, the AVR is defined by upper and lower voltage limit defined under the Configuration -> Power Settings. The *Sensitivity* that is chosen from (Normal, Reduced, Low) will define when the UPS will transfer to battery power - I have appended a screen shot from the users manual.