Cumulative Start-Up Time Counter; 10.Circuit-Breaker Failure Protection - ABB REM 610 Technical Reference Manual

REM 610
4.1.4.9.
4.1.4.10.
34
Motor Protection Relay
Technical Reference Manual
Note!
The unbalance element will be blocked during the tripping of the phase reversal
element.

Cumulative start-up time counter

The cumulative start-up time counter detects too frequent start-up attempts, which
cause overheating of the motor.
The start-up time of every motor start up is added to a register, 66 value. When the
register's value exceeds the set restart disable value, 66, any attempt to restart the
motor will be disabled.
The time to the next possible motor start up depends on the countdown rate of the
start-up time counter, 66 COOL /∆t, i.e. the rate at which the register's value
decreases. For instance, if the motor manufacturer allows a maximum of three 60 s'
motor start ups in four hours, 66 should be set to 2 x 60 s + margin = 121 s and 66
COOL/∆t to 60 s/4 h = 15 s/h; see the figure below.
66 value
[s]
150
Start 3
120
90
Start 2
60
30
Start 1
0
Fig. 4.1.4.9.-1 Cumulative start-up time counter operation
Note!
The register's value will decrease during motor start up as well.
Note!
If the emergency start has been activated, a motor start up will be allowed even
though the register's value exceeds the set restart disable value.
Circuit-breaker failure protection
The circuit-breaker failure protection (CBFAIL) detects situations where the circuit
breaker remains closed although the circuit breaker should have operated.
If a trip signal generated via output PO1 is still active and the current has not been
cut off on expiration of the CBFAIL set operate time (Trip Fail), the CBFAIL will
generate a trip signal via output PO2.
Next start possible
Restart disable activated > 66 (121 s)
1MRS 755537
t