Operating Instructions ACU
In the following settings, the starting current impression is used for the starting behavior:
ï€ Configuration 30 = 1xx (V/f control of asynchronous motor),
Operation Mode 620 =2, 4, 12 or 14
ï€ Configuration 30 = 4xx (FOR of an asynchronous motor)
ï€ Configuration 30 = 6xx (PSM: sensor-less, field-oriented control - DMR), synchronous
motor
13.1.1.2 Frequency Limit
The Starting Current 623 is impressed in configurations 1xx, 4xx and 6xx for control of the relevant
configuration until the Frequency Limit 624 is reached. Permanent operating points below the
frequency limit are only permissible if forced-ventilated motors are used.
The transition to the control method of the selected Configuration 30 takes place above the
frequency limit.
The Frequency Limit 624 is set automatically during guided motor commissioning in the field-
oriented configurations 4xx and 6xx. In V/f control configuration 1xx, parameter Frequency Limit
624 is not changed during guided motor commissioning.
13.1.1.3 Brake release time
In order to protect the motor holding brake against damage, the motor may only start after the
brake has been released. Startup to reference speed is effected only after the Brake Release Time
625 has elapsed. The time should be set such that it is at least as long as the time required for
releasing the holding brake. By using negative values for the parameter, release of the brake is
delayed. This can be done in order to prevent loads from falling down, for example.
13.1.2 Flux formation
Field-oriented control in the configurations 2xx and 4xx are based on separate regulation of the flux-
forming and torque-forming current components. Upon startup, the machine is magnetized and a
current is impressed first. With parameter Current during Flux-Formation 781, the magnetization
current I
sd
is set. With parameter Max. Flux-Formation Time 780 the maximum current impression
time is set.
The current impression is done until the reference value of the rated magnetizing current is reached
or the Max. Flux-Formation Time 780 is exceeded.
Current during flux formation
The factory setting of parameter Max. Flux-Formation Time 780 depends on parameter
Configuration 30:
1)
Configurations 1xx
2)
Configurations 2xx/4xx
3)
Configurations 6xx