Service Manual
Chapter 7 - Troubleshooting
Fault Identification
7 - 9
3x3 UPS Troubleshooting
Issue 2 - November 2001
7.5 - Fault Identification
The following table lists all alarm conditions shown on the Operator panel LCD, the cause of the alarm,
what checks should be carried out and possible solutions.
The activation of any alarm condition will illuminate the Red ALARM LED on the OPERATOR PANEL.
Table 7-1
General Fault Identification Check List
LCD MESSAGE
CAUSE
CHECKS
SOLUTIONS
INVERTER OFF
The inverter is OFF.
Check for other active alarm
messages.
If no other alarm indications are
seen:
At the initial inverter start up an
overload has been detected
(>125%).
Check the output current on each
phase.
Attempt to re-start the Inverter.
Reduce the load to acceptable level.
Re start Inverter via the Operator
Panel.
INVERTER OVERLOAD Continuos Overload on UPS
Output (between 100% and
125%).
Check the output current of each
phase.
Reduce the load to acceptable level.
Re-start Inverter via the Operator
Panel.
STATIC SWITCH
LOCKED
High Transient Loads on UPS
Output.
During initial closure of the
Bypass Static Switch an over
Load Current is detected. After 3
attempts the Bypass Static Switch
will be blocked.
Check Output Load and Restart
UPS.
Reduce the load to acceptable level.
Re start UPS.
BATTERY FAILURE
The automatic Battery Test has
failed.
Check condition of Battery.
Check Battery fuses (F1-4).
Replace defective battery
(see paragraph 6.3 on page6-8)
Replace Battery fuses.
BATTERY
PRE-ALARM
This indication warns that the
battery is approaching its
end-of-discharge voltage.
This alarm is Normally seen
during an extended Mains
Failure.
Confirm the alarm is genuine by
measuring the battery voltage.
If the alarm is not genuine replace
the Auxiliary DC-DC Converter.
STATIC SWITCH
FAILURE
Upon closing the Internal Static
Switch one or more phases are
missing at the UPS Output.
Check SCR of Bypass.
Check Bypass external connections.
Replace the faulty devices as
necessary.
MANUAL BYPASS ON
Manual bypass MCB (I3) is
closed.
Check the status of the MCB.
If the indicated circuit breaker status
does not agree with the actual
position then carry out a check of the
auxiliary contact monitoring circuit
and rectify as required.
MAINS OUT OF LIMITS The Mains input voltage (supply
to I1) is out of tolerance.
Check the status of the MAINS
INPUT MCB I1.
Check that the input voltage is
present, and within tolerances
(+/-10% of nominal).
If the MAINS INPUT MCB I1 has
opened, secure load to the bypass
supply and shutdown the UPS.
Check the input rectifier/converter
devices for fault before attempting to
restart unit.
Reconnect the Mains Supply to
module.
BYPASS LINE OUT OF
LIMITS
The Bypass input voltage (supply
to I2) is out of tolerance.
This condition is detected by the
Inverter Driver & Feedback Board
(Voltage detection or phase
rotation detector circuits are
active).
Check the status of the RESERVE
INPUT MCB I2.
Check that the Bypass (reserve)
input voltage is within tolerances
(+/-10% of nominal).
Check the phase rotation of the
Bypass supply.
If the RESERVE INPUT MCB I2 has
opened, secure load to the bypass
supply and shutdown the UPS.
Check the bypass devices for fault
before attempting to restart unit.
Reconnect the Mains Supply to
module.
If the alarm continues replace the
Inverter Driver and Feedback Board
(P/N OSDE0071).