A: INVT products support AC input or DC input. When the front-end rectifier provides a DC bus, you can connect the + and - terminals of VFD to the DC bus. When the production process requires multiple motors to work together,can adopt the DC common bus solution, some of the motors work in the electric state, and some work in the brake state. At this time, the feedback energy can be directly used in the electric mode motor, can save energy. Common DC bus solution don't need the input circuit breaker of each inverter, can save the costs. It is recommended to add a fuse protection between the bus and the motor.