70 Program features
WARNING: The motor needs to be rated to absorb the thermal energy
generated by flux braking.
Settings
Parameter 97.05 Flux braking (page 362).
DC magnetization
The drive has different magnetization functions for different phases of motor
start/rotation/stop: pre-magnetization, DC hold, post-magnetization and pre-heating
(motor heating).
Pre-magnetization
Pre-magnetization refers to DC magnetization of the motor before start. Depending
on the selected start mode (21.01 Start mode or 21.19 Scalar start mode), pre-
magnetization can be applied to guarantee the highest possible breakaway torque,
up to 200% of the nominal torque of the motor. By adjusting the pre-magnetization
time (21.02 Magnetization time), it is possible to synchronize the motor start and, for
example, the release of a mechanical brake.
Settings
Parameters 21.01 Start mode, 21.19 Scalar start mode, 21.02 Magnetization time
DC hold
The function makes it possible to lock the rotor at (near) zero speed in the middle of
normal operation. DC hold is activated by parameter 21.08 DC current control. When
both the reference and motor speed drop below a certain level (parameter 21.09 DC
hold speed), the drive will stop generating sinusoidal current and start to inject DC
into the motor. The current is set by parameter 21.10 DC current reference. When the