Cabinet designed crane drive lifts productivity and safety
08 February 2011
A compact AC drive with built-in crane control functions has been introduced by ABB for side-by-side installation within crane cabinets.
The low voltage AC drive, ACS850 with crane control program, can be preconfigured for use in stand-alone cranes. Typical applications include new and retrofit tower cranes in hoist, trolley and slew motions and industrial cranes in hoist, trolley and long travel motions.
Working in conjunction with the drive’s motor control platform, direct torque control (DTC), the crane control program provides smooth speed and torque control of the crane. Operating time is minimised and lifting capacity optimised through the crane control program’s load speed control, which maximizes the hoist speed for a given load.
The crane control program provides several application safety functions. For instance, the integrated mechanical brake control logic uses torque memory and pre-magnetising to build up the torque in the motor before opening or closing the brake. This avoids any sudden dropping or jerking movements.
The program’s slow down function limits the crane speed to a preset level when the crane is inside defined zones. The upper and lower end limit logic enables sensors to be connected directly to the drive to stop the crane safely when it reaches the end position of its travel.
The ready-made crane control program can interface with analog, digital or fieldbus systems, enabling a wide range of connectivity for start, stop and reference change signals. The program includes four different user sets for customising the parameter settings for multiple configurations. Each user set includes two different control places and an overriding emergency control place.
A crane load analyser shows the crane drive load profile. The crane user can select a signal to be monitored by the peak value logger. Six different maintenance counters can also be selected and configured to generate an alarm when the counter reaches a pre-defined limit.
The crane control program is available, built-in to the ACS850. The drive is rated from 1.1 to 500 kilowatts, 380 to 500 volts with IP20 protection class. With the smallest frame size only 93 mm wide, side-by-side cabinet mounting is straightforward.
The drive’s safety functions comply with European Union Machinery Directive 2006/42/EC.
A certified safe torque-off (STO) safety feature is built into the drive, which removes the torque from the motor shaft.
The drive features coated boards which protect the electronics and circuitry from humidity, thereby increasing the drive’s reliability.
A removable memory unit stores complete drive settings, including all user settings and motor data. If the drive needs to be replaced or updated, it can be done quickly without any special tools or knowledge.
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