Manual Bypass Mode_ Dual Input_ Parallel Units - Delta Modulon DPH series User Manual

3.2.11 Manual Bypass Mode_ Dual Input_ Parallel Units

In parallel mode, if one of the parallel UPSs needs maintenance, please first confirm that
the bypass AC source and each parallel UPS's STS module are normal. After confirmation,
please follow the procedures below to manually switch each of the parallel UPSs to manual
bypass mode.
1
Press each LCD's ON/ OFF button (
up to ask you if you want to power off the inverter. Please select 'YES'.
2 Turn on each Delta or non-Delta external maintenance bypass cabinet's Manual Bypass
Breaker or Switch (Q3).
3
Turn off each UPS's Bypass Switch (Q0).
4
Turn off each Delta or non-Delta external maintenance bypass cabinet's Input Breaker
or Switch (Q1), Bypass Breaker or Switch (Q2) and Output Breaker or Switch (Q4).
5 Turn off each external battery cabinet's breaker (Q5).
In manual bypass mode, all power inside the parallel UPSs is completely cut off and
maintenance personnel can perform maintenance safely. The connected critical loads will
be supplied by the manual bypass. During manual bypass mode, all parallel UPSs' tri-color
LEDs and LCDs are off. Please see Figure 3-28 for the path of electrical power through the
parallel UPSs in manual bypass mode.
Modulon DPH Series
WARNING:
1. In manual bypass mode, make sure that all of the breakers or switches (except
each Delta or non-Delta external maintenance bypass cabinet's Manual Bypass
Breaker or Switch (Q3)) are in the OFF position before working on any of the
parallel UPSs' internal circuits. This avoids electric shock.
2. After the power inside all parallel UPSs is completely cut off, there is no high
voltage in the parallel UPSs but in every Delta or non-Delta external maintenance
bypass cabinet. Do not touch any Delta or non-Delta external maintenance
bypass cabinet during UPS maintenance process to avoid electric shock.
3. During manual bypass mode, each parallel UPS's input power is completely cut
off and the connected critical loads are not protected.
For parallel UPSs, if you want to turn off one of the parallel UPSs for
maintenance, please make sure the total connected critical loads will not exceed the
remaining parallel units' total capacity.
) once and the 'POWER OFF?' screen will pop
3-28