Powertronix Quasar Service Manual page 90

Test Procedures
Primary and Secondary DC Bus Voltage Check (refer to Figure 7 7)
1.
2.
3.
The UPS is now safe to carry out further investigation.
Note: The half DC bus level can also be monitored if required by connecting the
Figure 7-7 DC Bus Voltage check
Check Secondary DC
bus between Fuse F3
& F2
765V DC
7 - 14
Remove the UPS top cover.
With a DVM check the secondary DC bus across F3 and F2 has fallen less than 20V dc.
With a DVM check the primary DC bus across F1 and F4 has fallen less than 20V dc.
DVM across the +ve or ve fuse and the DC common (neutral) bus bar as
shown in Figure 7 7.
F3
To Check Half Secondary DC bus Voltage check for 382V DC between Fuse
F3 and Neutral Bus. (a similar check can be carried out from F2)
Service Manual
F2
3x3 UPS
Issue 2 - November 2001