User`s manual

apfiff09 marine vacon • 153
24-
6
7.7.2 Closed loop settings
P2.7.2.1 Magnetizing current at start ID627
Defines the current that is applied to the motor when the start command is given in
closed loop control. At start this parameter is used together with Magnetizing time at
start to decrease the time when the motor is able to produce nominal torque. In closed
loop control output frequency is not forced to zero while magnetization current is applied
to motor.
P2.7.2.2 Magnetizing time at start ID628
Defines the time for how long magnetization current is applied to motor at start.
Magnetizing current at start is used to shorten the time when flux is at nominal level.
This will improve the torque performance at start. The time needed depends on the
motor size, value varying between 100 ms to 3 second. The bigger the motor the more
time it needs. Set this time so that the rotor flux is more than 90 % before speed is
released (Start Zero Speed Time ID615) or mechanical brake is released.
P2.7.2.3 Flux reference ID1250
Reference value for rotor flux. Rotor flux can be reduced by changing the magnetization
current. This, however, also affects the motor model making the torque calculations a
little less accurate. When using this parameter the motor model can compensate the
effect of the different magnetization current in torque calculations.



 













 




Flux
Flux
Fn 2xFn
50 %
25 %
75 %
Output frequency
P2.7.2.4 Flux Off Delay ID1402
The Flux off delay function will keep the motor magnetized after a stop command thus
making the next start faster because flux is already available in the motor. The function
is used e.g. in a system where several repeated starts are made in short cycles. The flux
level can be adjusted by parameter Stop State Flux .
0 = Flux is not maintained in the motor
>0 = Flux off delay in seconds.
-1 = Flux is maintained indefinitely in the motor