Dynamic Braking - Siemens MICROMASTER 440 Parameter Manual

Issue 01/06
3.27

Dynamic braking

P1237 Dynamic braking
CStat: CUT
P-Group: FUNC
Dynamic braking absorbs the braking energy. This parameter activates the function "Dynamic braking" and
defines the rated duty cycle of the braking resistor (chopper resistor). Dynamic braking is active when the
function is enabled and DC-link voltage exeeds the dynamic braking switch-on level, see below.
If a motor is quickly ramped down by the inverter or a big load is dropped by a lifting application, the motor
works in regenerating mode and saves energy back to the inverter. In this case the DC-link voltage of the
inverter raises. If that voltage gets too high (overvaltage , F0002), the inverter pulses are disabled and the
motor coasts to standstill. With dynamic braking the regenerative energy is fed by the chopper to the
external braking resistor and converted into heat. So it is possible to brake down the drive in a controlled
way.
Dynamic braking switch-on level
If P1254 = 0 :
V
DC , Chopper
otherwise :
V
DC , Chopper
Possible Settings:
0 Disabled
1 5 % duty cycle
2 10 % duty cycle
3 20 % duty cycle
4 50 % duty cycle
5 100 % duty cycle
Dependency:
This function is not available for for MM440 PX (FSFX and FSGX).
If used with DC braking enabled as well compound braking will take priority.
DC braking
P1233 > 0
?
yes
DC braking
enabled
Notice:
Initially the brake will operate at a high duty cycle dependant on the DC link level until the thermal limit is
approached. The duty cycle specified by this parameter will then be imposed. The resistor should be able to
operate at this level indefinitely without overheating.
~
MICROMASTER 440 Parameter List
6SE6400-5BB00-0BP0
Datatype: U16
Active: Immediately
= ⋅ ⋅ =
. 1 13 2 V . 1 13
mains
= ⋅
. 0 98 r 1242
Compound
no
braking
P1236 > 0
?
yes
Compound braking
enabled
Chopper resistor
MM4 B+
=
Chopper
control
~
Unit: -
QuickComm.: No
⋅ ⋅
2 P 0210
Dynamic
no
braking
P1237 > 0
?
yes
Dynamic braking
enabled
B-
=
~
Parameter Description
Level
Min: 0
2
Def: 0
Max: 5
no
disabled
147