Dc Braking - Siemens SINAMICS G120D Operating Instructions Manual

8.17.2

DC braking

Overview
DC braking is used for applications where the motor must be actively braked, but where the
converter is neither capable of energy recovery nor does it have a braking resistor.
Typical applications for DC braking include:
• Centrifuges
• Saws
• Grinding machines
• Conveyor belts
DC braking is not permissible in applications involving suspended loads, e.g. lifting equipment/
cranes and vertical conveyors.
Requirement
The DC braking function is possible only for induction motors.
NOTICE
Motor overheating as a result of DC braking
The motor will overheat if you use DC braking too frequently or use it for too long. This may
damage the motor.
• Monitor the motor temperature.
• Allow the motor to adequately cool down between braking operations.
• If necessary, select another motor braking method.
Function description
With DC braking, a constant braking current flows through the motor. As long as the motor is
rotating, the DC current generates a braking torque.
The following configurations are available for DC braking:
• DC braking initiated by a control command
• DC braking when falling below a starting speed
• DC braking when the motor is switched off
Converter with the control units CU240D-2
Operating Instructions, 10/2020, FW V4.7 SP13, A5E34262100B AH
Advanced commissioning
8.17 Electrically braking the motor
251