Table 100: Safety shutdown messages
Message Description
VSD – PHASE A
MOTOR DCCT
The motor current in each phase of the VSD is measured at the beginning of
the run command. The motor current at this time should measure very low.
This low value will be used as the zero current value for the rest of this run time.
The motor current is then monitored for the next 1.5 seconds to ensure that
a minimum amount of current is flowing to the motor. If at the end of the 1.5
second time a minimum of 25 amps peak is not detected, then this shutdown is
generated. When the condition clears, the chiller can be started after the clear
faults button is pressed.
VSD – PHASE B
MOTOR DCCT
See VSD – PHASE A MOTOR DCCT.
VSD – PHASE C
MOTOR DCCT
See VSD – PHASE A MOTOR DCCT.
VSD – PHASE
LOCKED LOOP
The VSD must be able to determine the input voltage frequency from the input
voltage measurement. If the input voltage frequency is not stable enough for
the VSD to make this determination, then this shutdown is generated. When
this condition clears, the chiller can be started after the clear faults button is
pressed.
VSD –
PRECHARGE
LOCKOUT
If the unit fails to complete pre-charge (due to VSD – PRECHARGE – LOW DC
BUS VOLTAGE or VSD – PRECHARGE – HIGH DC BUS VOLTAGE), the VSD shall
time 10 seconds before clearing the fault and allowing another pre-charge to
start. The unit’s fan(s) and water pump(s) shall remain energized during this
time. The VSD shall allow up to three consecutive pre-charge-related faults to
occur. After the third consecutive pre-charge-related fault, this shutdown is
generated. When the condition clears, the chiller can be started after the clear
faults button is pressed.
VSD –
RECTIFIER
PROGRAM FAULT
The VSD software contains a verification process to ensure that the correct
set of software is installed in the VSD logic board for the application. When
this condition clears, the chiller can be started after the clear faults button is
pressed.
VSD shutdown
– REQUESTING
FAULT DATA
The VSD has shut down the chiller and the control center has not yet received
the cause of the fault from the VSD, via the serial communications link. The
VSD shuts down the chiller by opening the Motor Controller VSD Stop contacts
(located on the VSD Logic Board and connected between TB6-16 and TB6-53 in
the control center). The Microboard in the control center then sends a request
for the cause of the fault to the VSD Logic Board over the serial link. Since
serial communications are initiated every 2 seconds, this message is typically
displayed for a few seconds and then replaced with one of the other VSD fault
messages.
YMC
2
Mod B with OptiView Control Center
126
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