4-22
469 Motor Management Relay
GE Power Management
4.4 S3 DIGITAL INPUTS
4 SETPOINT PROGRAMMING
4
4.4.17 DIGITAL INPUT FUNCTION: TACHOMETER
a) FUNCTION
Once the tachometer function is chosen for one of the assignable digital inputs, the setpoint messages shown
here will follow the assignment message. The period of time between each switch closure measured and con-
verted to an RPM value based on one closure per revolution. A trip and alarm may be configured such that the
motor or load must be at a certain speed within a set period of time from the initiation of motor starting. The
tachometer trip and alarm are ignored while the motor is stopped. The RPM value may be viewed in
A2 METERING\SPEED\TACHOMETER
.
b) EXAMPLE
An inductive proximity probe or hall effect gear tooth sensor may be used to sense the key on the motor. The
probe could be powered from the +24 V from the input switch power supply. The NPN transistor output could
be taken to one of the assignable switch inputs configured as a tachometer.
RATED SPEED:
3600 RPM
Range: 100 to 7200 RPM, step: 1
TACHOMETER
ALARM: Off
Range: Off, Latched, Unlatched
ASSIGN ALARM RELAYS:
Alarm
Range:
Alarm, Alarm & Auxiliary2, Alarm & Aux2 & Aux3,
Alarm & Auxiliary3, Auxiliary2, Aux2 & Aux3, Auxiliary3
TACHOMETER ALARM
SPEED: 10% Rated
Range: 5 to 100%, step: 1
TACHOMETER ALARM
DELAY: 1 s
Range: 1 to 250 sec., step:1
TACHOMETER ALARM
EVENTS: Off
Range: On, Off
TACHOMETER
TRIP: Off
Range: Off, Latched, Unlatched
ASSIGN TRIP RELAYS:
Trip
Range:
Trip, Trip & Auxiliary2, Trip & Aux2 & Aux3,
Trip & Auxiliary3
TACHOMETER TRIP
SPEED: 10% Rated
Range: 5 to 95%, step: 1
TACHOMETER TRIP
DELAY: 1 s
Range: 1 to 250 sec., step: 1
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
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ESCAPE
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ESCAPE
MESSAGE
ESCAPE