Maintenance Bypass Mode; Figure; Figure 5 - 5 Path Of Current Through The Ups In Maintenance Bypass Mode - Powerware 9320 Installation And Operation Manual

5.2.4 Maintenance Bypass Mode

An internal maintenance switch (IA1) is used to safely supply utility power to the system
output during periods of maintenance or repairs. Before this switch is used, the system
should be transferred to bypass. This switch has two positions: "O" (OFF) and "l" (ON).
When switched to "l" (ON), the bypass source supplies the commercial AC power to the
load directly.
While on internal (static) bypass, when a user rotates the maintenance switch from the
"O" (OFF) to the "l" (ON) position, the load is wrapped around the UPS, and power is
removed from the entire upper portion of the UPS allowing service work to be completed
on the UPS safely.
Figure 5–5 shows the path of electrical power through the UPS system when operating
in Maintenance Bypass mode.
CAUTION:
The critical load is not protected when the UPS is in the Maintenance Bypass mode.
DANGER:
LETHAL VOLTAGE PRESENT: This unit should not be operated with the cabinet
doors open or protective panels removed. Do not make any assumptions about the
electrical state of any cabinet in the UPS system.
Input Filter
Battery
Battery
Breaker
Figure 5–5. Path of Current through the UPS in Maintenance Bypass
Mode (UPS Module 3 in 9320-C03 systems only)
5-10
Maintenance Bypass Mode
K4
Static Switch
Rectifier
K1
F1
Breaker Contactors
Closed
Open
Powerware 9320 (10 kVA and 20 kVA) Installation and Operation
yp
IA1
Booster Inverter
K2
Battery
Charger
UPS Module 1
Switches
Main Power
Trickle Current
Energized
De-Energized
IA2
UPS Module 2
UPS Module 3
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