Lenze i950

13.5 Parameterisable motor funcons
13.5.1 DC braking
The control modes for asynchronous motors provide the opportunity to use the "DC‑br
aking"
funcon (DC-injecon braking) for braking. In this case, the motor control injects a DC current
the amplitude of which is adjustable.
Precondions
Using the "DC braking" funcon, the motor control injects a DC current, the amplitude of
which is adjustable in the 0x2B80 parameter. To this end, it is necessary that the current con-
trol is adapted to the corresponding motor. For seng and opmising the current controller,
see Current controller. ^ 267
Details
The funcon can be used as follows:
1.
"DC braking" can be parameterised via bit 6 in the Lenze control word 0x2830.
In this case, the motor system itself can be used as an energy converter.
This opon is useful if
•
the system is not provided with a brake resistor required for absorbing the braking
energy. This method requires that a sucient braking torque can be achieved with "DC
braking".
•
the power of the brake chopper to be transformed is limited and thus must be exclu-
sively used for the main drives of the DC network. The quality of the deceleraon ramp
via "DC braking" is sucient for auxiliary drives and unburdens the brake chopper.
•
a fan drive is to be braked in the V/f characterisc operaon.
2.
"DC br
aking" can be parameterised as a response to minor faults.
An example of a minor fault is the error of an encoder of an asynchronous machine. Due to
the error, the quick stop funcon cannot be executed anymore. An
alternave is provided
by the guided shutdown with a minor deceleraon via the "DC braking" funcon.
Parameter
Address Name / seng range / [default seng] Info
0x2B80 Current for DC-injecon braking
0.00 ... [0.00] ... 500.00 A
Braking current for DC-injecon braking
Conguring the motor control
P
arameterisable motor funcons
DC braking
251