Siemens MICROMASTER 420, Operating Instructions Manual

Page: 123 / 190

Issue 07/04 3 Functions
MICROMASTER 420 Operating Instructions
6SE6400-5AA00-0BP0
123
The DC brake can therefore support a braking operation from approx. < 10 Hz or
prevents / minimizes the increase in the DC link voltage for regenerative braking.
This is realized because energy is directly absorbed in the motor. The essential
advantage and the main application of the DC brake is the fact that a holding
torque can be generated at standstill (0 Hz). For instance, this is important for
applications where after positioning, any motion in the mechanical system / product
itself can result in waste.
DC braking is especially used for:
Centrifuges
Saws
Grinding machines
Conveyor belts
Sequence
➀
1. Enabled using P1233
2. DC braking is activated with the OFF1 or OFF3 command (refer to Fig. 3-51)
3. The inverter pulses are inhibited for the duration of the de-magnetizing time
P0347.
4. The required braking current P1233 is then impressed for the selected braking
time P1232. The status is displayed using signal r0053 bit 00.
The inverter pulses are inhibited after the braking time has expired.
0 t
OFF1/OFF3
ON
t
1
t

f

P1233
1
tt
P0347
OFF2
DC braking
OFF2
DC braking active
r0053
Bit00
Fig. 3-51 DC braking after OFF1 / OFF3