Multilin 139 series - Setting RTD Trip;Alarm Temperatures

sensor temperature reaches 130°C the main relay trips shutting down the motor.
The relay cannot be reset until
the RTD temperature falls below the trip value.
Different alarm and trip temperatures can be factory preset upon request The
nominal factory settings are
recommended for use with class 8 winding insulation
or class F insulation with class B temperature use. It
is possible to change the
alarm and trip temperatures in the field
if required. To make these changes a
200 ohm potentiometer
is connected across terminals A, B, C as shown in Figure
3-4 to simulate the RTO sensor
The potentiometer
is varied until a voltmeter across terminals 0 and E reads the
desired alarm or trip temperature. The preset alarm or trip temperature trimpot
in the relay
as shown in Figure2-3 is then adjusted until the auxiliary relay {alarm)
or main relay (trip) just picks up. There
is a short time delay after the threshold
temperature
is reached before the relay is activated. Care should be taken to
ensure the settings of the RTD calibration trimpots are not altered .
• " FIGURE
3-4 SETTING RTD TRIP/ALARM TEMPERATURES
RTD OPTION TERMINALS
E
D
0-2V DC
METER
c
B
A
2000HM
POTENTIOMETER
27
Courtesy of NationalSwitchgear.com