Using conventional crane and trolley motion controls, the load suspended on the hook will pendulum due to travel acceleration or deceleration. The operator, controlling a critical or easily damaged load must anticipate the motion of the load while it is swinging dangerously from side to side. With an inexperienced operator, the risks to people, product, and equipment is significant. A 5-ton load swinging into a piece of equipment can cause damage easily cost tens of thousands of dollars. The risk to personnel between the swinging load and fixed machinery is unimaginable.
Even with an experienced operator, productivity is dramatically reduced (up to 25%) because of the requirement to slow the travel speed in anticipation of the swinging and also waiting for the load to stop swinging to lower the load. With a swinging load, the crane operator must always divide their attention between maneuvering the crane and performing actions to reduce sway. Even then, the potential for injury exists for someone inadvertently walking into the path of a swinging load.
Magnetek Sway Control System
Sway Control Systems (SCS) improve productivity by allowing the crane operator to concentrate on load engagement and disengagement rather than focusing on minimizing load swing. An SCS also enhances the accuracy of load placement and reduces material damage caused by incidental contact of swinging loads.
Magnetek’s sway control system custom software is embedded in the current IMPULSE Series 4 variable frequency drives for new or existing crane control systems without the need for external programmable logic controllers or costly height measurement devices.
Manual adjustments due to swinging loads in travel motions account for as much as 25% of the operating cycle. “Utilizing sway control on overhead or gantry cranes can reduce operator fatigue and the need for extensive operator training.”A crane with sway control allows an operator to use full speed commands for all movements, meaning shorter cycle times. Field tests have demonstrated that sway control improves productivity by 25-50%. Properly designed and adjusted sway control systems can minimize load sway by 85-95%, decreasing the risk of damage and personal injury.
Sway control is able to increase throughput in automated handling systems by allowing higher operating speeds and faster acceleration and deceleration rates than would be possible with a manually controlled system. A fully automated system controls the load, prevents dangerous sway at every phase, and stops the load precisely at the target, every time.
Closed loop systems are best utilized on high-cycle outdoor systems such as container cranes that are subject to external influences like wind, justifying the higher initial cost and maintenance expense.
Open loop systems have an economic advantage over mechanical means or closed loop systems with feedback and are best applied in industrial applications where wind and external influences may be of less significance.
For more information about sway control contact your local CRANE 1 office.