Options; System; Backfeed Protection - ABB DPA UPScale ST40 User Manual

8 Options

8.1 System

8.1.1 Backfeed protection

The UPS backfeed protection prevents any hazardous voltage or energy from being present on the
UPS input AC terminals after interruption of the input AC power.
The backfeed protection is implemented in the DPA UPScale ST by internal backfeed protection
contactors (K1 and K2) as shown in the wiring diagram below.
Mains backfeed contactor
K1
(option)
Bypass backfeed contactor
K2
(option)
Order Number
04-0727
04-0728
04-0729
04-0730
04-3229
Modifications reserved
Page 67/79
Fig 8.1.1-1: Backfeed protection
In the event of an AC failure, prevents the occurrence of any
hazardous voltage at the rectifier mains terminal due to
backfeed from the power modules sourced by the battery
In the event of an AC failure, prevents the occurrence of any
hazard voltage at the bypass input terminal due to backfeed
from the power modules sourced by the battery
Backfeed protection ST40
Backfeed protection ST60
Backfeed protection ST80
Backfeed protection ST120
Backfeed protection ST200