Circuit Bypass Mode; System Protection Features; Operating The Ups (Cont'd) - Toshiba 1500 Plus Series Operation Manual

5.0 Operating the UPS
5.1 Operation Modes
5.1.3 Circuit-bypass mode
Power
input plug
Fuse
IEC-320
Power flow in circuit-bypass mode.
If the UPS unit is severely overloaded or develops an internal fault, the power flow
is automatically switched from the unit's main circuit to the bypass circuit mode.
Power flow through the bypass is shown in the above illustrations. This change-
over occurs automatically in approximately 4 milliseconds. The switching period
is not long enough to cause interruptions to occur in most UPS equipment loads.
The energy flow must be transferred manually from the UPS's bypass
circuit back to the inverter circuit after first correcting the fault. Toggle the
STOP/RUN switch (on the unit's front panel) first to STOP and then back to RUN.
This procedure resets the UPS and transfers back to inverter. During circuit-
bypass mode the AC-Input LED is ON, the On-Line LED is OFF, and the Fault
LED may be ON or OFF.(See Section 9.2 Panel Layout).
5.2

System Protection Features

The schematic shown below depicts the electrical locations of the protection devices on
the UPS.
Input
Overcurrent
Abnormal
Fuse
Input
Input
Transformer
Bypass circuit
UPS
main
circuit
Input
Transformer
+
UPS batteries
-
Rectifier/
Charger/
Chopper
+
Batteries
Low Battery
Overheating
Level
5 - 2
*Isolation only
for 1500 plus
series (600VA)
Output
Transformer
Inverter
Current Limit Overvoltage/
Overload Undervoltage
UPS
receptacles
(rear panel)
IEC-320
= power flow
*Isolation only
for 1500 plus
series (600VA)
Output
Output
Output
Transformer