Dc Braking - Siemens SINAMICS G150 Operating Instructions Manual

Functions, Monitoring, and Protective Functions
9.2 Drive Functions
9.2.9.4

DC braking

Description
DC braking is only available for induction motors. It is used preferably when braking in a
hazardous situation, if controlled braking via the drive is no longer possible (for example, in
the event of a power failure, an EMERGENCY OFF, etc.) or if no regenerative infeed is
used. .
DC braking is activated via p1231 = 4 or via p1231 = 14. It can be initiated via an input signal
p1230 (signal = 1) or a fault response.
Activation of DC braking via input signal
p1231 = 4 (internal armature short-circuit/DC braking)
If DC braking is activated by the digital input signal, the first step is that the pulses are
blocked for the duration of the demagnetization time (p0347) of the motor in order to
demagnetize the motor - the parameter p1234 (speed at the start of DC braking) is ignored.
Then the braking current (p1232) is applied as long as the input is initiated in order to brake
the motor or hold it at standstill.
p1231 = 14 (DC braking below the starting speed)
DC braking is initiated, if during operation a 1-signal is pending at the binector input p1230
and the actual speed is below the starting speed (p1234).
After the preceding demagnetization (p0347) of the motor for the period set in p1233, the
braking current p1232 is applied and subsequently switched off automatically.
Cancellation of the input signal for DC braking
If DC braking is withdrawn, the drive returns to its selected operating mode.
The following applies:
● With vector control (closed-loop controlled with or without encoder):
● In V/f mode:
450
The drive is synchronized with the motor frequency if the "Flying restart" function is
activated, and then returns to closed-loop controlled mode. If the "Flying restart" function
is not active, the drive can only be restarted from standstill without overcurrent fault.
With the "Flying restart" function activated, the converter frequency is synchronized with
the motor frequency, and the drive will then return to V/f mode. If the "Flying restart"
function is not activated, the drive can only be restarted from standstill without
overcurrent fault.
Converter cabinet units
Operating Instructions, 03/2012, A5E03263466A