Emergency Restart; Resetting The 169 Relay - GE 169 Instruction Manual

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GE Power Management
3 SETUP AND USE
LEARNED START CAPACITY - An OVERLOAD TRIP caused by the exhaustion of motor thermal capacity will cause
a lock-out. A relay reset will not be allowed until the memory has discharged to 15% thermal capacity used. At this
point the relay can be reset.
If the Start Inhibit feature is enabled (SETPOINTS, page 5) a motor start will not be allowed until the thermal memory
has discharged sufficiently to make the start possible. The 169 relay uses the "LEARNED Start Capacity required"
(ACTUAL VALUES, page 6) to determine if a start is possible. If sufficient thermal capacity is available for a start,
the start will be successful. Thus the START INHIBIT lock-out time is adjusted to allow for optimum motor usage. To
override a START INHIBIT or OVERLOAD TRIP lock-out condition the Emergency Restart feature can be used. If
the Start Inhibit feature is disabled the OVERLOAD TRIP lock-out time will not be adjusted by the learned starting
capacity value and will represent the time for the thermal memory to discharge to 15% thermal capacity used. Thus
the lockout time will equal 85% of the STOPPED COOL TIME when Start Inhibit is disabled. When Start Inhibit is
enabled the OVERLOAD TRIP lock-out time will represent the time for the thermal memory to discharge to the
"LEARNED Start Capacity required" value.
If the "ENABLE AUTO-RESET OF START TRIPS?" setpoint is enabled then the relay will automatically reset once
the lockout time has elapsed.
Before the 169 Plus relay has learned the actual Start Capacity required by the motor this value will default to 40%.

3.21 Emergency Restart

When production or safety considerations become more important than motor protection requirements it may be
necessary to restart a faulted motor. Momentarily shorting together the Emergency Restart terminals will discharge
the thermal memory to 0% so that the relay can be reset after an OVERLOAD TRIP. In this way the lock-out is
avoided. The Emergency Restart feature will also reduce the relay's starts/hour counter by one each time to
terminals are shorted together, so that a STARTS/HOUR TRIP can be defeated.
When RTD input to thermal memory (SETPOINTS, page 5) is enabled and the Emergency Restart feature is used,
thermal capacity will be reduced to 0% only for as long as the Emergency Restart terminals are held shorted (note:
it may take up to 11 seconds for the "Thermal Capacity Used" display to change to 0%). When the Emergency
Restart terminals are opened again the thermal capacity will change to what is used according to the maximum
stator RTD temperature and Figure 3-4. Thus, momentarily shorting the Emergency Restart terminals with RTD
input to thermal memory enabled may not reduce the thermal capacity used to 0% when the motor is hot.
Shorting the Emergency Restart terminals together will have no effect unless the motor is stopped. Thus having
these terminals permanently shorted together will cause the memory to be cleared when the motor stops. This will
allow for an immediate restart after an OVERLOAD TRIP.
Caution is recommended in the use of this feature since the 169 relay's thermal protective functions will be
overridden and it is possible to damage the motor if Emergency Restart is used.

3.22 Resetting The 169 Relay

Resetting the 169 relay after a trip must be done manually by pressing the RESET key, or by shorting together the
External Reset terminals. Alarm functions can cause latched (manual reset) or unlatched (automatic reset) output
relay operation depending on the RELAY ALARM LATCHCODE (SETPOINTS mode, page 5). A latched relay will
stay activated until the RESET key is pressed or the External Reset feature is used.
If a trip/alarm condition persists (e.g. a high RTD temperature), or if the relay has locked out the motor, pressing the
RESET key will cause the flash message,
RESET NOT POSSIBLE -
Condition still present.
to be displayed. However, shorting the Emergency Restart terminals together will reduce the lock-out time, allowing
the relay to be reset immediately.
Note: If RTD input to thermal memory is enabled (SETPOINTS, page 5) the lock-out time may not be reduced
to 0 minutes since the thermal capacity available is dependent on the RTD bias curve (Figure 3-4) and the
maximum stator RTD temperature (see section 3.21).
If the External Reset terminals are permanently shorted together the relay will be reset immediately when motor
conditions allow (e.g. when the lock-out time runs out). The 169 relay cannot be reset after a Differential Input Trip or
Spare Input Trip until the contacts connected across the Differential or Spare Input terminals have been opened.
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