Lenze 8400 StateLine - Manual (Page 226)

5 Motor control (MCTRL)
5.11 Braking operation/brake energy management
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Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
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5.11 Braking operation/brake energy management
When braking electrical motors, the kinetic energy of the drive train is fed back regeneratively to the
DC bus. This energy results in a boost of the DC-bus voltage.
• Several different strategies can serve to avoid DC-bus overvoltages:
• Use of a brake resistor
• Stopping of the ramp function generator if brake chopper threshold exceeded (RFG_Stop)
• Use of the "inverter motor brake" function
(from version 04.00.00)
• Combination of the above named options
• In the case of inverters with a 3-phase supply, the following is also possible:
• Coupling of the inverters in a DC-bus connection
• Recovery of regenerative energy with a regenerative module

Stop!
If the connected brake resistor is smaller than required, the brake chopper can be
destroyed!
• Appropriate protective measures are described in subchapter " Avoiding thermal
overload of the brake resistor ". ( 234)
If no brake resistor or regenerative module is used, the overvoltage switch-off (" oU ") may
respond, e.g. in case of short deceleration times during feedback operation.  Error
messages of the operating system ( 444)