text: <s>[INST] Power Flex 700 , VFD failure due input short circuit Summary: VFD failure rate is high. What are possible reason. If failure due to DC bus voltage( 745 V), how can I lower DC bus voltage.We are using Power Flex 700 VFD in crane hoisting application. we have enabled torque proving mode. We are facing problem that failure rate of these drive is very high. On average every 9-12 month VFD power input side ( Rectifier) get shorted and fuse blown up. Our observation is while crane tools lowering DC bus voltage is reaching around 745 Volt. I would like to know. 1. Is due to this DC bus voltage , VFD failure rate is high. 2. How can I control DC bus voltage to lower level. Thanks, Shashi [/INST] 745V bus voltage is normal for a 480V input. If your input voltage is not 480, then yes, 745 bus voltage might not be correct. It would help if you gave specifics - exact drive model number, motor nameplate data, line voltage, design of system - that is, do you have a dynamic braking resistor, brake chopper module, line reactor, load reactor? Have you put a power monitor on the system? \\n </s>