Technical data

Drive functions
7.2 Basic functions
Function Manual
192 Function Manual, 06/2012, 6SL3097-4AB10-0BP4
For the function with contactor feedback signal, you will need to wire the feedback inputs of
both command data sets (CDS = 2) p1235[0..1].
The external armature short-circuit is only supported for rotary-type permanent-magnet
synchronous motors (p0300 = 2xx).
DC brake (induction motors)
The DC brake is activated by setting parameter p1231 = 4 (internal armature short-circuit/DC
brake). It can be triggered via an input signal p1230 (signal = 1) or a fault response:
Activation of DC brake with BI p1230
If the DC brake is activated with the digital input signal, the pulses will first be inhibited for
the motor demagnetization time p0347 in order to demagnetize the motor. Next, braking
current p1232 is injected into the DC brake for as long as the signal = 1 at the binector input,
in order to decelerate the motor or hold it at standstill.
When the DC brake is released, the drive will return to its initial operating mode (it is only at
this point that the motor is remagnetized).
In this mode, parameter p1234 (speed at the start of DC braking) is ignored.
DC brake as a fault response
If the DC brake is activated as a fault response, the motor will first be decelerated in field-
oriented mode along the OFF1 ramp (defined using p1082, p1121) until it reaches the speed
at the start of DC braking (p1234). If the fault in response to which braking has been
triggered is an encoder fault, braking will not be controlled (p1234 is ignored). Next, the
pulses will be inhibited for the motor demagnetization time p0347 in order to demagnetize
the motor. DC braking will then commence for the DC braking duration set in p1233. If an
encoder signal is available (neither encoder fault nor encoderless operation), the DC brake
will remain active for the set duration p1233 but will be deactivated at the latest when the
standstill threshold p1226 is undershot.
NOTICE
In encoderless operation or with strong field weakening in particular, when the rotor is
rotating, there is no guarantee of controlled operation being restored once the DC brake
function has been deactivated. In such cases, the drive will shut down with a fault message
with OFF2 response.