6 Drives control
6.4 Braking
DC1 variable frequency drive 12/13 MN04020003Z-EN www.eaton.com 115
6.4 Braking
Various braking functions can be configured:
• DC braking,
• Generative braking (brake chopper),
• Mechanical braking (actuation).
The brake functions allow you to reduce undesired coasting and long
coasting times. Mechanical braking also ensures safe operating states.
6.4.1 DC-braking
With DC braking, the variable frequency drive supplies the three-phase stator
winding of the three-phase motor with DC current. This generates a
stationary magnetic field which induces a voltage in the rotor while the rotor
is in motion. As the electrical resistance of the rotor is very low, even small
induction can generate high rotor currents and thus a strong braking effect.
As the speed slows down, the frequency of the induced voltage and with it
the inductive resistance drops. The resistive load becomes more effective
and increases the braking effect.
￫
DC braking is not suitable for holding loads or for intermediate
braking. Nor for intermediate braking.
NOTICE
DC braking will cause increased motor heating. Accordingly,
make sure to configure a braking torque that is as low as
possible using the voltage amplification (P-11) and braking
duration (P-32) parameters.
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