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4–44
Courtesy of NationalSwitchgear.com
to use this option. When ordering a motor with RTDs, the 100 Ω platinum DIN 43730 type is
the preferred choice for optimum sensitivity and linearity. Other RTDs that can be selected
are 100 Ω nickel, 120 Ω nickel and 10 Ω copper.
•
RTD 1-3 APPLICATION: RTDs can be located in the stator windings or the bearings.
Specify the location of each RTD in this setpoint. The application name selected here
will be displayed as part of the alarm and trip message. If a particular RTD input is not
used, this setpoint should be set to off.
•
RTD 1-3 TYPE: This setpoint must be programmed to the type of RTD for each of the
RTDs connected. The factory default is 100 Ω platinum but 100 Ω nickel, 120 Ω nickel,
or 10 Ω copper can also be connected to each input.
•
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
RTD 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
Fahrenheit or vice versa, setpoints
and
3\RTD 1-3 TRIP
S4: PROTECTION\ TEMPERATURE\RTD 1-3\RTD 1-3 ALARM
will automatically be scaled to 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
any unused RTD terminals.
S1:239 SETUP\PREFERENCES\TEMPERATURE DISPLAY
is changed from Celsius to
S4: PROTECTION\TEMPERATURE\RTD 1-
239 MOTOR PROTECTION RELAY – INSTRUCTION MANUAL
CHAPTER 4: PROGRAMMING
.
S1: 239
S4:
and
S4:
should be set to off for
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