Siemens SINAMICS S120 Function Manual page 192

Basic functions
6.8 Armature short-circuit brake, internal voltage protection, DC brake
External armature short-circuit braking
The external armature short-circuit is activated via p1231 = 1 (with contactor feedback
signal) or p1231 = 2 (without contactor feedback signal). It is initiated when the pulses are
canceled.
This function controls an external contactor via output terminals, which then short-circuits the
motor through resistors when the pulses are canceled. Armature short-circuit braking has the
advantage with respect to a mechanical brake that at the start of braking (at a high speed),
the braking effect is initially high. However, at lower speeds, the braking effect is significantly
decreases - this is the reason that we recommend a combination with a mechanical brake.
A prerequisite for the use of the external armature short-circuit is:
● One of the following motor types was parameterized:
In case of incorrect parameterization (e.g. induction motor and external armature short-circuit
selected), an error 7906 "Armature short-circuit / DC brake parameterization error" is
generated.
1
r0046.4
p1230
(0)
≥1
(r0046.19 = 1)
r0046.20
Figure 6-3 External armature short-circuit braking with/without contactor feedback signal
Internal voltage protection (booksize)
The internal voltage protection is activated with p1231 = 3. It is initiated when the pulses are
canceled.
The internal voltage protection is used to protect the drive group when the pulses are
cancelled. This is realized by short-circuiting a half bridge in the power unit (Motor Module).
192
– Rotating permanent-magnet synchronous motor (p0300 = 2xx)
– Linear permanent-magnet synchronous motor (p0300 = 4xx)
p1231 = 1
p1235
r0002 = 19
r1239.0
p1236 = 200 ms
T
0
=1
p1237 = 200 ms
0 T
1
DI
DO
+24 V
F07905
&
A07904
&
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
2000 µs
M
~
3
p1231 = 1
p1231 = 2
Drive Functions