Maintenance
Copyright © 2007-2018 Eaton Corporation. All Rights Reserved.
IPN 997-00012-03 B2 Issue B2 July 2018
125
Problem
Possible Cause
Required Action
String Fail Alarm
The Battery Mid-point
Monitoring system has detected
a voltage imbalance in one of
the battery strings.
See Battery Mid-point Monitoring in the
dc power system Installation and
Operation Guide.
A Battery Mid-point Monitoring
sense wire is disconnected.
Check the sense wires.
I/O board Power/Comms
OK LED is off
I/O board is not powered or
faulty.
Check connection to YH3 on I/O board.
See Connections on page
Replace I/O board if faulty.
I/O board Power/Comms
OK LED is flashing.
I/O board is responding to an
Identify
command from the
SC300.
None, this is normal operation. See
LVD Status LED(s) (on I/O
board) are on.
LVD contactor is energized.
None, this is normal operation.
LVD Status LED(s) are off
(I/O board Power On LED is
on).
LVD contactor is de-energized. None, this is normal operation.
LVD Status LED(s) flashing. The contactor is in the wrong
state (SC300 internal state does
not match signal from contactor
auxiliary switch).
Check the electrical and mechanical
operation of the contactor and auxiliary
switch.
Check all wiring and connectors. See
Connections on page 5.
LVD Type
setting is incorrect.
Check
LVD Type
setting.
LVD contactor(s) not
operating.
LVD settings incorrect.
Check LVD is enabled and set to correct
values. See details on page
Check that the LVD manual control is set
to AUTO. See details on page 49.
Check that the contactor is correctly
configured and mapped to the I/O
board. See details on page 53.
Contactor is disconnected.
Check the control and dc power cables
are connected. See details on page
System has no dc output
(rectifiers are on).
Load fuse or disconnect device
open.
Check for open fuse or disconnect device.
LVD contactor has disconnected
the load.
Use the web to check LVD is enabled and
set to correct values. (LVD status LED on
the I/O board is on when contactor is
energized.)
Check that the I/O board is connected
(Power LED is on).
Check that the LVD control and power
cables connections on page 5.
Check the connections from the load bus
to the LVD.
System has no battery input Battery disconnect device or
fuse open.
Check for open battery disconnect device
or fuse.
LVD has disconnected the
battery because ac supply is off
and the battery is fully
None. The battery will be automatically
reconnected when the ac supply is
restored.
