Application Examples For Closed-Loop Motor Control; Electrically Braking The Motor; Electrical Braking - Siemens SINAMICS G120C Operating Instructions Manual

Advanced commissioning
8.21 Electrically braking the motor
8.20.4

Application examples for closed-loop motor control

Additional information for setting the closed-loop motor control in certain applications is
provided in the Internet:
•
support.industry.siemens.com/cs/de/en/view/103156155)
•
support.industry.siemens.com/cs/ww/en/view/77491582)
8.21

Electrically braking the motor

8.21.1

Electrical braking

Overview
Braking with the motor in generator operation
If the motor brakes the connected load electrically, it converts the kinetic energy of the motor
into electrical energy. The electrical energy E released when braking the load is proportional
to the moment of inertia J of the motor and load and to the square of the speed n. The motor
attempts to transfer the energy on to the converter.
Main features of the braking functions
DC braking
DC braking prevents the motor from transferring the braking en‐
ergy to the converter. The converter impresses a DC current into
the motor, which brakes the motor. The motor converts the brak‐
ing energy E of the load into heat.
• Advantage:The motor brakes the load without the converter
having to process regenerative power.
• Disadvantages:Significant increase in the motor temperature;
no defined braking characteristics; no constant braking torque;
no braking torque at standstill; braking energy E is lost as heat;
does not function when the power fails
Compound braking
One version of DC braking. The converter brakes the motor with a
defined ramp-down time and superimposes a DC current on the
output current.
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Engineering and commissioning series lifting equipment/cranes
Commissioning a compressor with closed-loop pressure control
Operating Instructions, 02/2023, FW V4.7 SP14, A5E34263257B AK
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SINAMICS G120C Converters