JOHNSON CONTROLS
226
FORM 201.23-NM2
ISSUE DATE: 09/25/2020
SECTION 8 - MICROPANEL
X indicates the system and YYYYYYY indicates the
system is in a “FAULT” condition and will restart or
“LOCKOUT” and will not restart until the operator
clears the fault using the keypad.
Motor Current Overload (Software) Fault
The Motor Current Overload will compare the highest
of the 3 phases of motor current per compressor to the
compressor’s 105% FLA ADJUST (overload) potenti-
ometer setting on the VSD Logic Board. If the current
exceeds the setting continuously for 20 seconds, the
compressor will trip.
This safety will lock out a system on the 1st fault and
shut down with a controlled ramped shutdown. The
fault will be an individual system/compressor fault for
all systems. A sample Status display fault is shown be-
low:
SYS X YYYYYYYY MOTOR CURRENT OVERLOAD
X indicates the system and YYYYYYY indicates the
system is in a “LOCKOUT” condition and will not re-
start until the operator clears the fault using the keypad.
Motor Current Overload (Hardware) Fault
The Motor Current Overload will compare the highest
of the 3 phases of motor current per compressor to the
compressor’s overload ADJUST potentiometer setting.
If the current exceeds the setting continuously for 30
seconds, all compressors will fault and shut down im-
mediately.
The fault will be a unit fault and will lock out all sys-
tems on the first fault. A sample Status display fault is
shown below:
UNIT YYYYYYYY
MOTOR CURRENT OVERLOAD
YYYYYYYY indicates the unit is in a "Lockout" con-
dition and will not restart until the operator clears the
fault using the keypad.
IGBT Gate Driver (Hardware) Fault
The unit’s phase bank assembly(s) contains one IGBT
gate driver control board per compressor. These boards
monitor the saturation voltage drop across each of the
six IGBT’s while gated on. If the IGBT’s saturation
voltage exceeds the prescribed limit, the gate driver
will make the determination that a short circuit is pres-
ent. This in turn will cause the system to trip. During
normal operation, the voltage drop across a saturated
IGBT is low. When a short or shoot occurs, the ex-
tremely high current causes the voltage across the de-
vice to increase. When the electronic hardware on the
IGBT Gate Driver Board senses the current rise, it im-
mediately turns off all IGBT’s in the module and the
system will shut down immediately.
Additionally, if the IGBT’s Gate Driver board’s power
supply voltage falls below the permissible limit, this
same fault will be generated.
This is an auto-restart safety that will lock out on the
3rd fault in 90 minutes. The fault will be a system fault
for all units. Following is the Status display fault mes-
sages for all systems.
SYS X YYYYYYYY GATE DRIVER
X indicates the system and YYYYYYY indicates the
system is in a “FAULT” condition and will restart or
“LOCKOUT” and will not restart until the operator
clears the fault using the keypad.
High Baseplate Temperature (Software) Fault
Each phase bank assembly contains one liquid cooled
heatsink to cool both the inverter power modules and
the converter SCR/Diode modules. Each compressor’s
inverter power module (6 IGBT’s and Gate Driver
Board) contains an internal temperature sensor (5K
ohm at 25°C) to monitor the baseplate temperature.
On two compressor chillers, the outputs from System 1
and System 2 sensors are each compared in software to
a limit of 218°F. If either sensor exceeds this limit, the
unit will fault and shut down with a controlled ramped
shutdown.
On 3 compressor chillers, the baseplate temperatures
on compressors 1 and 3 are OR’d together and the
highest of the two temperatures is compared in soft-
ware to a limit of 232°F. Compressor #2 will have its
individual power module sensor compared in software
to a limit of 232°F. If the limit is exceeded by either of
the 2 inputs, the unit will fault and shut down with a
controlled ramped shutdown.
3 compressor chillers operate at higher
baseplate temperature compared to 2 or
4 compressor chillers.
Summary of Contents for YCIV Series
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