Siemens CU230P-2 HVAC Parameter Manual page 295

p3856[0...n] Compound braking current / Compound I_brake
PM240 Access level: 3
Can be changed: U, T
Min
0.00 [%]
Description: Compound braking current is used to define the amount of DC current that is produced on stopping the motor dur-
ing V/f operation to further increase the DC brake function.
The compound brake is a superimposition of the DC brake function with the regenerative brake (net braking along
the ramp) after OFF1 or OFF3. This permits braking with controlled motor frequency and minimum power input into
the motor. Effective braking without using additional hardware components is obtained by optimizing the ramp
down time and the compound brake.
Dependency: The compound braking current is only activated if the DC link voltage exceeds the threshold value in r1282.
The compound brake does not operate:
- when the DC brake is active (refer to p1230, r1239)
- as long as the motor is not magnetized (e.g. for flying restart)
- for vector control (p1300 >= 20)
- for synchronous motors (p0300 = 2xx)
Caution: Generally, increasing the braking current improves the braking effect when stopping the motor. However, if the
value is set too high, then the drive can be tripped (shut down) as a result of overcurrent.
Recommendation: p3856 < 100 % * (r0209 - r0331) / p0305 / 2
The compound brake generates a current in the motor with a ripple manifesting the rotational frequency. The higher
the braking current is set, the higher the resulting ripple, especially when the Vdc(max) control is simultaneously
active (refer to to p1280).
Note: The parameter value is entered relative to the rated motor current (p0305). The compound brake is deactivated with
p3856 = 0%.
r3859.0 CO/BO: Status word compound brake / ZSW compound brake
PM240 Access level: 3
Unit: -
Description: Status display of the compound brake.
Bit field: Bit Signal name
00 Compound brake
Dependency: Refer to: p3856
p3880 BI: ESM activation / ESM activation
Access level: 3
Can be changed: U, T
Min
-
Description: Sets the signal source to activate emergency operation (ESM = Essential Service Mode) via digital inputs.
Permissible values:
p0722.x for high-active switch-in signals
p0723.x for low-active switch-in signals
Where x = 0, 1, 2, 3, 4, 5, 11 or 12
© Siemens AG 2009 All Rights Reserved
SINAMICS G120 Control Units CU230P-2 Parameter Manual (LH9), 11/2009
Calculated: -
Scaling: PERCENT
Max
250.00 [%]
Calculated: -
Scaling: -
1 signal
Active
Calculated: -
Scaling: -
Max
-
Parameters
List of Parameters
Data type: FloatingPoint32
Data set: DDS, p0180
Factory setting
0.00 [%]
Data type: Unsigned32
Data set: -
0 signal
Inactive
Data type: U32 / Binary
Data set: -
Factory setting
0
FP
-
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