ABB ACS 800 Series, Firmware Manual

Page: 67 / 340

Program features
67
Flux braking
The drive can provide greater deceleration by raising the level of magnetisation in
the motor. By increasing the motor flux, the energy generated by the motor during
braking can be converted to motor thermal energy. This feature is useful in motor
power ranges below 15 kW.
The drive monitors the motor status continuously, also during the Flux braking.
Therefore, Flux braking can be used both for stopping the motor and for changing
the speed. The other benefits of Flux braking are:
• The braking starts immediately after a stop command is given. The function does
not need to wait for the flux reduction before it can start the braking.
• The cooling of the motor is efficient. The stator current of the motor increases
during the Flux braking, not the rotor current. The stator cools much more
efficiently than the rotor.
Settings
Parameter 26.02 .
Flux braking
No Flux braking
t (s)
Motor
Flux braking
No Flux braking
f (Hz)
T
Br
T
N
20
40
60
(%)
T
N
= 100 Nm
T
Br
= Braking Torque
Speed
50 HZ / 60 Hz
120
80
40
0
5 10 20 30 40 50
1
2
3
4
5
120
80
40
0
5 10 20 30 40 50
1
2
3
4
5
f (Hz)
Braking Torque (%)
f (Hz)
Flux braking
No Flux braking
1
2
3
4
5
2.2 kW
15 kW
37 kW
75 kW
250 kW
Rated Motor Power