Siemens SINAMICS G130 Operating Instructions Manual page 409

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If DC braking is withdrawn, the drive returns to its selected operating mode.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):
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.
● For U/f control:
With the "Flying restart" function activated, the converter frequency is synchronized with
the motor frequency, and the drive will then return to U/f mode. If the "Flying restart"
function is not activated, the drive can only be restarted from standstill without
overcurrent fault.
DC braking as a fault response
Activation via p0491 = 4, p2101 = 6 (armature short-circuit, internal/DC braking)
If DC braking is activated as a fault response, the motor is initially braked in field-oriented
mode along the braking ramp up to the threshold set in p1234 (speed at the start of DC
braking). The slope of the ramp is identical with that of the OFF1 ramp (parameterized using
p1082, p1121). Subsequently, the pulses are disabled for the period in p0347
(demagnetizing time) in order to demagnetize the motor. DC braking will start for the duration
set in p1233 (DC braking duration).
● If an encoder is present, braking will continue until the speed drops to below standstill
threshold p1226.
● If no encoder is present, only the period in p1233 is effective.
Activation via p1231 = 5 (DC braking for OFF1/OFF3)
DC braking is activated with OFF1 or OFF3
● If the motor speed ≥ p1234, the motor is braked down to p1234. As soon as the motor
speed is < p1234, the pulses are disabled and the motor is demagnetized.
● If the motor speed at OFF1/OFF3 is already < p1234, the pulses are immediately
inhibited and the motor is demagnetized.
DC braking is activated for the period set in p1233 (DC braking duration), then switched off.
When OFF1/OFF3 is prematurely canceled, then normal operation is resumed.
DC braking as emergency braking of a fault response remains active.
Function diagram
FP 7017
Inverter chassis units
Operating Instructions, 07/2016, A5E00331449A
Technology functions - DC braking
Functions, monitoring, and protective functions
9.2 Drive functions
409