Figure 1.2 Single Line Diagram-Bypass Operation: Load Fed Through Static Bypass Line - Mitsubishi Electric 9900B Series Owner Technical Manual

MITSUBISHI
ELECTRIC
In the event of a UPS module failure during Parallel Operation, the critical load power will be
continuously supplied and shared by all other UPS units.
CAUTION: For protection, the Bypass Input circuit breaker (MCCB) of the UPS
B) Bypass Operation: Load Power supplied through UPS internal static bypass line.
Figure 1.2 Single Line Diagram - Bypass Operation: Load Fed Through Static Bypass Line
CB
Bypass
Input
User
supplied
MCCB
CB
AC
input
User
supplied
MCCB
Referring to Figure 1.2: The Internal Bypass line is a hard-wired line through 52S, which
supplies the critical load with unconditioned bypass input power. Upon switching to the Internal
Bypass line, the Static Transfer Switch (STS) line through CB3 supplies the power immediately.
Then the Internal Bypass line through 52S supplies the power. In the event of switching to the
Bypass line, the power to the critical load will be uninterrupted. The purpose of this Internal
Bypass line is to route power to the critical load while the UPS module (converter and inverter)
is de-energized, and during startup before the system is operating on the UPS module.
Each UPS internal static bypass line will equally share the power supplied to the critical load
whenever the system is in Parallel Operation.
MITSUBISHI ELECTRIC 9900B SERIES UPS
9900B SERIES UPS
OWNERS / TECHNICAL MANUAL
and cables are field supplied and field installed (see WARNING 4
on page 1-5).
UPS Module
CONVERTER /
CHARGER
CB1
Battery
CB2
Cabinet
External
BATTERY
52S
CB3
Static Transfer
Switch
INVERTER
52C
Power Flow
Not in Use
Page Number:
1-9
Output