GE 239 Instruction Manual page 80

TEMPERATURE
°C
-40
-30
-20
-10
0
10
20
30
40
4–44
Courtesy of NationalSwitchgear.com
• RTD 1-3 TRIP and RTD 1-3 ALARM: Alarm and trip settings for stator RTDs depend on
the motor stator insulation type. Class B insulation rating is the factory default with
alarm and trip levels of 110°C and 130°C respectively. Higher temperatures can be
selected for other insulation classes. Consult the motor manufacturer for suitable
settings if higher temperature insulation is installed in the motor. Bearing temperature
settings are empirically set. Default settings are 75°C alarm and 90°C trip. The alarm/
trip will occur immediately after the input becomes equal to or exceeds the
temperature setting. Once a motor is running for several hours the actual
temperature can be monitored and the settings reduced. Over time a bearing problem
such as a loss of lubricant will show up as an increased temperature. Consequently, a
setting close to the actual operating temperature is desirable providing it does not
generate nuisance alarms from ambient temperature changes or load variations.
Temperature display units are set as either Celsius or Fahrenheit depending on the
selection of the setpoint
temperature readings from all of the RTDs may be displayed. If RTD application is set
to , the display for that RTD will be "no RTD". When the setpoint
OFF
SETUP\PREFERENCES\TEMPERATURE DISPLAY
or vice versa, setpoints
S4: PROTECTION\TEMPERATURE\RTD 1-3\RTD 1-3 TRIP
PROTECTION\ TEMPERATURE\RTD 1-3\RTD 1-3 ALARM
the proper setting.
RTD Sensor Failure
• RTD SENSOR FAILURE ALARM: If an RTD becomes open circuited during use, the
ACTUAL VALUES display for that RTD will be "no RTD". Readings from the disconnected
RTD will then be ignored for overtemperature protection. The 239 relay will generate
an alarm to warn of the faulty RTD if this setpoint is enabled. Setpoints
PROTECTION\TEMPERATURE\RTD 1-3\RTD 1-3 TRIP
PROTECTION\TEMPERATURE\RTD 1-3\RTD 1-3 ALARM
unused RTD terminals.
Table 4–3: RTD Resistance VS. Temperature (Sheet 1 of 2)
100 Ω
PLATINUM
°F
-40 84.27 Ω
-22 88.22 Ω
92.16 Ω
-4
14 96.09 Ω
32 100.0 Ω
50 103.9 Ω
107.8 Ω
68
86 111.7 Ω
104 115.5 Ω
S1:239 SETUP\PREFERENCES\TEMPERATURE DISPLAY
is changed from Celsius to Fahrenheit
and
100 Ω 120 Ω NICKEL
NICKEL
79.13 Ω 92.76 Ω
84.15 Ω 99.41 Ω
89.23 Ω 106.41 Ω
94.58 Ω 113.0 Ω
100.0 Ω 120.0 Ω
105.6 Ω 127.2 Ω
111.2 Ω 134.5 Ω
117.1 Ω 142.1 Ω
123.0 Ω 149.8 Ω
239 MOTOR PROTECTION RELAY – INSTRUCTION MANUAL
CHAPTER 4: PROGRAMMING
. RTD
S1: 239
and
S4:
will automatically be scaled to
S4:
S4:
should be set to off for any
10 Ω
COPPER
7.490 Ω
7.876 Ω
8.263 Ω
8.649 Ω
9.035 Ω
9.421 Ω
9.807 Ω
10.19 Ω
10.58 Ω