
4: Operating Procedures
42
TS_619_00 PW9000DPA S2 User Manual 13/3/17
4.1.3 General warnings
4.2
Operating instructions
Under normal operating conditions all the UPS modules are running and operating in the on-inverter mode.
This chapter contains the following procedures:
• How to start the UPS system from a fully powered-down condition
(See paragraph 4.3)
.
• How to start the UPS system when it is initially operating on the maintenance bypass
(See paragraph 4.4)
.
• How to transfer the load to the maintenance bypass and stop the system
(See paragraph 4.5)
.
• How to shut down the entire UPS system
(See paragraph 4.6)
.
• Operating in ‘on bypass’ mode
(See paragraph 4.7)
.
4.3
How to start the UPS system from a fully powered-down condition
You should familiarise yourself with the operation of the external maintenance bypass circuit operation before using this
procedure.
Initial conditions:
This procedure assumes the following initial conditions:
• The UPS maintenance bypass switch is open.
• The UPS system input supply isolated.
• The external UPS system output isolator is open.
WARNING:
The procedures given below must be performed by a trained operator.
WARNING:
When the UPS system is operating on
BYPASS
or via the
MAINTENANCE
BYPASS
SWITCH
, the
load supply is unprotected if the bypass mains supply fails. It is essential that the load user is informed of this
possibility before you select these operating modes.
WARNING:
When the UPS is shut down, power is still applied to the UPS modules and the cabinet input/
bypass terminals unless the input/bypass mains is isolated at the mains switchgear panel. In a single cabinet
installation it is not permissible to turn off the external input/bypass mains supply when the load is connected
via the internal maintenance bypass switch (IA1) as this will also disconnect the load power.
IMPORTANT NOTE
In the following procedures, all references to the ‘Maintenance Bypass Switch’ apply to the internal
maintenance bypass switch (IA1) in the case of a single cabinet if it is not connected to an external
maintenance bypass facility.
If an external maintenance bypass facility is installed (standard in a parallel-cabinet system) all
references to the ‘Maintenance Bypass Switch’ apply to the maintenance bypass switch in the
external facility.
CAUTION: In a multi-cabinet system ALWAYS use the external maintenance bypass facility. DO NOT operate
the internal cabinet maintenance bypass switches (IA1).
Key Point:
In order to reduce the possible effects of any high inrush currents that might occur when the load is
initially turned on, we recommend that you power-up the load when the UPS system is operating on
maintenance bypass, as described in this procedure.