ABB REM 610 Technical Reference Manual page 116

REM 610
116
Motor Protection Relay
Technical Reference Manual
Example 1
Start-up current of the motor
Start-up time of the motor
One hot start allowed
Ambient temperature
At an ambient temperature of 40°C the internal FLC equals the FLC of the motor.
Thus, the start-up current of the motor is 6.2 x the internal FLC.
The safe stall time setting is calculated or selected from the trip curves at prior load
1 x FLC. In the figure below, a safe stall time of 30 seconds is selected, permitting
a start-up time slightly longer than the one stated by the motor manufacturer; see the
figure below.
t/s
50
40
30
20
10
5
4
3
2
1.05
1
1 2 3
Fig. 5.1.2.2.-1 Selected safe stall time 30 s
Example 2
Start-up current of the motor
Start-up time of the motor
One hot start allowed
Ambient temperature
At an ambient temperature of 20°C the internal FLC is 1.09 x FLC of the motor.
Thus, the start-up current of the motor is 6.2/1.09 = 5.69 x the internal FLC.
6.2 x FLC
11 s
40°C
t
6x
[s]
120
60
30
20
15
10
5
2.5
4 5 6 8 10
I/I
n
6.2 x FLC
11 s
20°C
1MRS 752263-MUM