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SECTION 32 - MOTOR MONITORING
FORM 160.54-M1
ISSUE DATE: 10/25/2019
JOHNSON CONTROLS
JCI COMPANY CONFIDENTIAL
32
Motor Winding Phase
TB1-1,2
A Temperature
TB1-4,5
B Temperature
TB1-7,8
C Temperature
• VSD THERMISTOR Enables and displays the 3
motor winding temperatures, as reported by the
thermistors via the VSD to Microboard serial
communications. The Motor Monitoring Board is
commanded to not read any of its winding sensor
inputs.
The enabled winding temperatures for phase A, B and
C, along with the Average Winding Temperature, are
displayed on the MOTOR DETAILS Screen. They
are displayed over the range of: RTD = 32.0 399.5°F;
Thermistors = 31.2 412.5°F. If the Winding Tempera-
ture Protection setpoint (On the MOTOR DETAILS
Screen) is set to DISABLED, no temperatures are dis-
played and the heading, text and data boxes do not ap-
pear. Individual winding temperatures can be disabled
using the Temperature Disable setpoint (on the MO-
TOR SETPOINTS Screen). When an individual tem-
perature is disabled, the temperature data boxes do not
appear. Any RTD that registers as an open is consid-
ered invalid and displays as XXX.X.
The Average Winding Temperature is the average of
all enabled and valid motor winding temperatures.
Any winding temperature that registers as open, out of
range or disabled is not used in the calculation. When
RTD’s are used for winding temperature measurement,
there are a maximum of 6 temperatures used to calcu-
late the average. When thermistors are used, there are a
maximum of 3 temperatures used to calculate the aver-
age. The text description and data box do not appear
when the Winding Temperature Protection setpoint is
set to disabled.
On the microboard, the winding temperatures are com-
pared to warning and safety shutdown thresholds. These
thresholds are entered using the Winding Setup setpoint
(on the MOTOR SETPOINTS Screen). The HIGH
WINDING TEMPERATURE SHUTDOWN safety
threshold is programmable over the range of 266 320°F
(default 311). The WINDING HOTSPOT ALLOW-
ANCE safety shutdown threshold is programmable over
the range of 0 18°F (default 0). The values programmed
for these safety thresholds are displayed in the respec-
tive data boxes on the MOTOR SETPOINTS Screen.
When any of the enabled winding temperatures ex-
ceeds [High Winding Temperature Shutdown threshold
minus 18°F] for at least 3 continuous seconds, Warn-
ing Motor High Winding Temperature is displayed.
This warning automatically clears when all winding
temperatures decrease below the warning threshold.
This warning not occur when the Winding Tempera-
ture Protection setpoint is set to disabled on the MO-
TOR DETAILS Screen. Also, it will not act on any
RTD input registering as an open RTD or any individ-
ual winding temperature sensor that has been disabled
with the Temperature Disable setpoint on the MOTOR
SETPOINTS Screen.
When either of the following conditions occur, a safety
shutdown is performed and Motor-High Winding Tem-
perature is displayed:
• Any of the enabled motor winding temperatures
exceeded the programmed High Winding Temper-
ature Shutdown Threshold plus the programmed
Winding Hotspot Allowance threshold for 3 con-
tinuous seconds.
-OR-
• The Average Winding Temperature has exceed-
ed the programmed High Winding Temperature
Shutdown threshold for 3 continuous seconds.
The chiller can be restarted after all winding tem-
peratures decrease to at least 18° F (10° C) below the
shutdown threshold and the COMPRESSOR Switch
is placed in the Stop-Reset position). This safety shut-
down will not occur when the Winding Temperature
Protection setpoint is set to disabled on the MOTOR
DETAILS Screen. Also, it will not act on any RTD
input registering as an open RTD or any individual
winding temperature sensor that has been disabled
with the Temperature Disable setpoint on the MOTOR
SETPOINTS Screen.
See
for RTD resistance/voltage
for Thermistor resis-
tance/voltage table.
