564 Appendix A - ACS380 in crane applications
When the Conical motor control function is enabled and the start command is given,
the motor flux ramps up over the normal level (100%) to the start flux level (
76.22
)
during a flux ramp-up time (
76.25
). The ramp-up time makes sure that the brake
opens faster and there is minimal roll-back that can cause a load dip. The start flux
level is kept as the reference for a hold time (
76.24
) to make sure that there is enough
time for the brake to open.
After the start flux hold time is over, the normal flux level (100%) is activated for
normal running. The flux ramps down from the start flux level to the normal level
(100%) during a flux ramp-down time (
76.26
).
When the stop command is given, the drive decelerates the motor. When the motor
speed (
01.01
)
decreases below the zero speed limit (
21.06
), the motor starts to use
the stop flux level (
76.23
) as the flux reference. The flux ramps down from the normal
level (100%) to the stop flux level during the ramp-down time. When the actual motor
flux reaches the stop flux level, the brake closes.
Timing diagram
This diagram shows brake opening and closing as well as the normal running flux
levels.
Speed (rpm)
t (s)
t (s)
01.01
76.24
76.26
100% flux
76.25
76.22
Flux ref (%)
(
76.27
)
Start
command
76.23
Rotor
released
ACS380 FW.book Page 564 Friday, May 4, 2018 4:18 PM
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