Parameterisable Motor Functions; Dc Braking - Lenze i950 Commissioning Manual

13.5

Parameterisable motor functions

13.5.1

DC braking

The control modes for asynchronous motors provide the opportunity to use the "DC‑braking"
function (DC-injection braking) for braking. In this case, the motor control injects a DC current
the amplitude of which is adjustable.
Preconditions
Using the "DC braking" function, the motor control injects a DC current, the amplitude of
which is adjustable in the 0x2B80
trol is adapted to the corresponding motor. For setting and optimising the current controller,
see Current controller.
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Details
The function 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 option is useful if
the system is not provided with a brake resistor required for absorbing the braking
•
energy. This method requires that a sufficient 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 deceleration ramp
via "DC braking" is sufficient for auxiliary drives and unburdens the brake chopper.
a fan drive is to be braked in the V/f characteristic operation.
•
2. "DC braking" 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 function cannot be executed anymore. An alternative is provided
by the guided shutdown with a minor deceleration via the "DC braking" function.
Parameter
Address Name / setting range / [default setting]
0x2B80 Current for DC-injection braking
0.00 ... [0.00] ... 500.00 A
parameter. To this end, it is necessary that the current con-
Info
Braking current for DC-injection braking
Configuring the motor control
Parameterisable motor functions
DC braking
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