3 SETUP AND USE
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GE Power Management
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3.13 Rapid Trip / Mechanical Jam Setpoints
These setpoints are found in SETPOINTS mode, page 1 and are used to protect the driven mechanical system from
jams. If used, this feature is active only after the motor has successfully started, and will cause relay activation in
the event of a stall while the motor is running.
A current surge of 150% to 450% of motor full load for from 0.5 to 125.0 seconds during motor operation, depending
on the setpoints chosen, will cause the relay assigned to the Rapid Trip / Mechanical Jam function to become active.
To disable the Rapid Trip / Mechanical Jam function the "RAPID TRIP/MECH. JAM TRIP LEVEL" setpoint should be
set to "OFF". The "RAPID TRIP TIME DELAY" setpoint will then be disregarded by the relay.
Note: This feature is not recommended for use with systems that experience overloads as part of normal
operation.
3.14 Short Circuit Setpoints
The Short Circuit protective function provides overriding protection for any large phase current. Complete protection
from phase-to-phase and phase-to-ground faults is provided with this feature. This feature is active at all times,
including during motor starts, unless the "SHORT CIRCUIT TRIP LEVEL" is set to OFF. The setpoints are in
SETPOINTS mode, page 1.
The phase current short circuit trip level can be set from 4 to 12 times motor full load current. The trip can be
instantaneous or can be delayed by up to 20.5 seconds to facilitate coordination with system switchgear. If this
feature is not desired the "SHORT CIRCUIT TRIP LEVEL" setpoint should be set to "OFF". If this is done the relay
will disregard the "SHORT CIRCUIT TIME DELAY" setpoint.
3.15 Immediate Overload Alarm Level Setpoint
The Immediate Overload Alarm Level setpoint is found in SETPOINTS mode, page 1. It is adjustable from 1.01
XFLC to 1.50 XFLC. An output relay activation will occur immediately when the average phase current goes over the
setpoint value. This function can never cause latched (manual reset) relay operation.
3.16 Stator RTD Setpoints
The 169 relay has 6 sets of 4 terminals available for the connection of RTDs to monitor the temperature of the stator
windings. If fewer than 6 RTDs are to be used they should be connected to the lowest numbered RTD connections
on the rear of the relay. The stator RTD setpoints are found in SETPOINTS mode, page 2. The "# OF STATOR
RTDS USED" setpoint should be chosen to represent the number of RTDs actually connected to the motor stator
windings. Thus if 3 RTDs are connected to the stator, the "# OF STATOR RTDS USED" setpoint should be set to 3,
and the 3 RTDs should be connected to the terminals for RTD1, RTD2, and RTD3 (terminals #1-12).
There are individual trip and alarm setpoints for each RTD. A relay activation will occur when any one of the RTD
temperatures goes over its corresponding setpoint value. The maximum stator RTD temperature at any time will be
used for relay thermal calculations.
When the relay is in ACTUAL VALUES mode the temperature readings from all of the RTDs may be displayed. If no
connection has been made to any RTD terminals the display for that RTD will be "noRTD". If the "# OF STATOR
RTDS USED" setpoint is stored as 3, only the maximum temperature from RTD1, RTD2, and RTD3 will be used for
motor temperature calculations. Thus, in this case, RTD4, RTD5, and RTD6 may be used for any other RTD
temperature monitoring function desired.
If a stator RTD becomes open circuited during use, the ACTUAL VALUES display for that RTD will be "noRTD".
Readings from the disconnected RTD will then be ignored. The 169 relay will enter TRIP/ALARM mode to warn the
user of the faulty RTD if the "No Sensor Alarm" is enabled (SETPOINTS, page 5). After a stator RTD temperature
trip or alarm setpoint is exceeded the 169 relay will not allow the active output relays to be reset until the
temperature has fallen 4 C below the exceeded setpoint.
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