Two-in-one drive is regenerative

ABB Automation - formerly ABB Industrial Systems - has launched a regenerative AC drive combining accurate speed control, Direct Torque Control (DTC) and line braking. The ACS 611 drive is aimed at applications such as cranes, centrifuges and winding machines with ratings up to 55 kW.

The drive incorporates two inverters in one frame. An active inverter replaces the usual diode rectifier on the incoming AC power, cutting harmonics and ensuring the delivery of an almost sinusoidal supply. The extra inverter also offers full four-quadrant operation and a two-way flow of energy, allowing the drive to divert excess energy from a braking motor back into the electrical supply.

The drive is said to switch between maximum motoring and maximum generating power in less than 5ms, allowing it to adapt to dynamic changes in the motor load. This means that the ACS 611 can achieve large energy savings in applications where energy from a braking motor is fed back into the electrical network.

In addition, if there is a drop in the line voltage, the drive will quickly adapt to maintain a stable DC voltage for ride-through performance. By re-directing unused electrical energy, the ACS 611 also eliminates the need for large braking resistors, which take up valuable space and waste considerable amounts of energy. This, in turn, reduces the drives` ventilation and cooling requirements and cuts plant costs further.

The ACS 611 is available in six power ratings in the range 11-55kW, all using the same frame size. There is an extensive collection of application macros for cranes, motion control and winding machines.