AUG 23, 2013
Arcomet, a construction crane manufacturing and rental company, has chosen a Control Techniques crane control system for its new generation of rapid assembly cranes: the T33, A33, A40 and A45 Eco City cranes. The system, which includes Unidrive SP and Commander SK variable speed drives, has delivered market-leading levels of flexibility, safety, comfort and energy savings.
The Control Techniques solution, which was implemented in collaboration with Arcomet’s engineering department, involved fitting each rapid assembly crane with three electric motors and three drives: a lifting motor controlled by a 15 kW Unidrive SP, an aligning motor controlled by a 7.5 kW Unidrive SP and a turning motor controlled by a 4 kW SKC Commander.
The system allows: faultless deployment at the touch of a button, precise positioning with millimeter accuracy, sway dampening, optimum use of load curves by working at maximum speed for any given weight, automatic compensation for supply current variations, remote control, and power restrictions at 20 kVA on the A30 and A40 ranges to allow easy start up via generator or mains network. The speed adjustment feature also uses variable rotation speed motors to achieve considerable energy savings.
Additional achievements in improving the operation of the cranes that have been made include: quiet start up with high torque without current spikes, smooth movement, intelligent and precise positioning with counter steering during lifting and aligning movements, and controlled lifting and aligning functions.
Rapid assembly cranes are usually used in the construction of houses, flats and office buildings. They are often installed on small building sites with restricted assembly space and they have limited power. Therefore, they must be compact and they must be able to be assembled and dismantled by as few people as possible.
Raf Smeets, a senior engineer at Arcomet, says: “With our new concept we are market leaders, thanks to the productive collaboration with Control Techniques. The increased functionality is highly appreciated by building contractors.”
Hans Vandevoort, who has recently purchased an A40 Eco City for his company, says: “We made our choice by giving priority to quality and reliability. The A40 Eco City stands out because of its flexibility. In particular, the crane driver appreciates being able to counter steer, a clever function enabling him to set down the load quickly and correctly without any sway. This function simulates the former repetitive starting and stopping controls. The braking effect of the damping winding device on the motor ensures that the crane driver feels in perfect control of the movement of the load at all times.”
Smeets adds: “We want to continue the development of our drive system and so we are thinking of introducing the option of reducing the operation of the crane from 400 V to 230 V in order to operate at even lower powers. We are also looking into the possibility of transferring our concept to tower cranes. We are leaving it up to Control Techniques to look into all this.”