Siemens SINAMICS V20 Series - Page 72

Commissioning
5.6 Function commissioning
SINAMICS V20 Inverter
72 Operating Instructions, 07/2012, A5E03728167
Compound braking
For compound braking (enabled using P1236), DC braking is superimposed with
regenerative braking (where the inverter regenerates into the DC-link supply as it brakes
along a ramp). Effective braking is obtained without having to use additional components by
optimizing the ramp-down time (P1121 for OFF1 or when braking from f1 to f2, P1135 for
OFF3) and using compound braking P1236.
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Setting parameters
Parameter Function Setting
P1236[0...2] Compound braking current [%] This parameter defines DC level superimposed on AC
waveform after exceeding DC-link voltage threshold of
compound braking. The value is entered in [%] relative to
rated motor current (P0305).
Range: 0 ... 250 (factory default: 0)
P1254 Auto detect Vdc switch-on levels This parameter enables / disables auto-detection of switch-on
levels for Vdc_max controller.
= 0: Disabled
= 1: Enabled (factory default)
It is recommended to set P1254 = 1 (auto detection of Vdc
switch-on levels enabled). Note that auto detection only works
when the inverter has been in standby for over 20s.
WARNING
For compound braking, regenerative braking is superimposed on the DC braking (braking
along a ramp). This means that components of the kinetic energy of the motor and motor
load are converted into thermal energy in the motor. This can cause the motor to overheat if
this power loss is too high or if the brake operation takes too long!