DC braking

The "DC braking" function generates a braking torque by injecting a DC current into the motor. The function can be used to shorten the braking of a load with high mass inertia. Another application is holding the motor shaft before starting or while stopping.
 
NOTICE
Avoid long-time activation of the "DC braking" function with a high braking current or a high braking voltage!
Possible consequences: thermal motor overload
▶
Only use the "DC braking" function with applications in which the load is only occasionally stopped.
 
▶
Do not activate the "DC braking" function longer than necessary.
 
 
 
Preconditions
The "DC braking" function can only be activated if the inverter is enabled.
This function is not available for the SL-PSM motor control mode 0x2C00 (P300.00).
 
Details
The function can be used as follows:
1.
Automatically when the motor is started.
 
2.
Automatically when the motor is stopped.
 
3.
Manually (via the flexible I/O configuration).
 
The three options can also be combined, for instance automatic DC braking when starting and stopping the motor.
For further details and configuration examples, see the following subchapter:
Example: Automatic DC braking when starting the motor 
Example: Automatic DC braking when stopping the motor 
Activating DC braking manually 
Migration of Lenze Inverter Drives 8200/8400 
 
Parameter
Address
Name / setting range / [default setting]
Information
0x2B84:001
(P704.01)
DC braking: Current
(DC braking: Current)
0.0 ... [0.0] ... 200.0 %
Braking current for DC braking.
–
100 % = Rated motor current 0x6075 (P323.00)
 
0x2B84:002
(P704.02)
DC braking: Automatic hold time
(DC braking: Hold time autom.)
0.0 ... [0.0] ... 1000.0 s
Hold time for automatic DC braking.
–
The "Automatic DC braking" function is active for the time set here.
 
–
1000.0 = infinite
 
Note!
Do not set this parameter to the value "1000.0" (infinite) if the DC braking is used during the start. The "Infinite" setting can be used to lock the rotor for an indefinite time while a stop is active. However, ensure here that the longer DC braking does not cause a thermal overload of the motor!
0x2B84:003
(P704.03)
DC braking: Automatic operating threshold
(DC braking: Threshold autom.)
0.0 ... [0.0] ... 599.0 Hz
Operating threshold for automatic DC braking.
–
With the setting 0, the "Automatic DC braking" function is deactivated.
 
0x2B84:004
(P704.04)
DC braking: Demagnetization time
(DC braking: Demagnet. time)
0 ... [100] ... 150 %
–
From version 04.00
 
In the default setting, the DC braking is activated after the standard demagnetising time has elapsed. This parameter can be used to adapt the time.
–
100 % = Default demagnetization time 0x2B84:005 (P704.05)
 
Note!
A too short demagnetising time can cause an overcurrent error!
0x2B84:005
(P704.05)
DC braking: Default demagnetization time
(DC braking: Def. demag. time)
–
Read only: x ms
 
–
From version 04.00
 
Display of the standard demagnetising time as a setting help for the user.
–
This time is calculated by the inverter:
Demagnetising time = 7 * rotor time constant
 
0x2B84:006
(P704.06)
DC braking: Inverter disable
(DC braking: Inverter disable)
1 = behaviour in case of automatic DC braking as with the Lenze Inverter Drives 8200/8400.
The behaviour of the Lenze Inverter Drives 8200/8400 in case of automatic DC braking is different: In case of these inverters, after the auto DCB hold time has elapsed, the motor is deenergised (by means of pulse inhibit) until the setpoint exceeds th auto DCB operating threshold. In order to make a migration to the i500 inverter series easier, the setting "1" serves to activate the same behaviour in the i500.
0
Disabled
1
Activated
 

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