Siemens 440 - Manual (Page 147)

Issue 01/06 Parameter Description
MICROMASTER 440 Parameter List
6SE6400-5BB00-0BP0
147
3.27 Dynamic braking
P1237 Dynamic braking Min: 0
CStat: CUT Datatype: U16 Unit: - Def: 0
P-Group: FUNC Active: Immediately QuickComm.: No Max: 5
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.
0210 P 2 13 . 1 V 2 13 . 1 V mains Chopper , DC
⋅ ⋅ = ⋅ ⋅ =
If P1254 = 0 :
otherwise :
1242 r 98 . 0 V Chopper , DC
⋅ =
Dynamic braking switch-on level
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
no
DC braking
enabled
Compound
braking
P1236 > 0
?
Compound braking
enabled
Dynamic
braking
P1237 > 0
?
Dynamic braking
enabled
disabled
no no
yes yes
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.
Chopper resistor
Chopper
control
B-
=
~
~
B+
=
~
MM4
Level
2