6.7.1 Monitoring braking transistorGeneral• The function "monitoring braking transistor" is standard for housing P with brakingoption.• It must be wired according to the wiring diagrams.• This circuit offers a direct protection in case of a defective braking transistor.• If the braking transistor is defective, a relay opens the terminals K1 / K2.• Terminals K1 / K2 are integrated into the holding circuit of the coupling relay for theinput contactor, so the mains voltage is switched off in error case.• Regenerative operation is also secured by the internal fault disconnection.• Chapter => Wiring Diagrams contains examples of how to wire the integrated relayvia terminals K1 / K2.6.7.2 external braking resistor without temperature monitoringExternal braking resistors are available for air-cooled and liquid-cooled devices.ATTENTION Only "intrinsically safe" braking resistors are permissible for operationwithout temperature monitoring.An intrinsically safe braking resistor will melt internally like a fuse in case of overloaddue to overheating. There is no short circuit or earth fault. As a result, the drive con-verter changes to "Error! Overvoltage" with the next deceleration process (when thebraking resistor is required).+PAPBR U3Figure 23: Intrinsically safe braking resistor without temperature monitoringTechnical data and design of intrinsically safe brakingresistors.https://www.keb.de/fileadmin/media/Manuals/dr/ma_dr_safe-braking-re-sistors-20106652_en.pdf76eLecTrIcAL INSTALLATION
