Assembly tasks intersect in manufacturing, fastening and joining, and fabrication work. That becomes clearer when you consider that utility-scale turbines are so large they must be manufactured in sections or modules and then assembled close to the job site. Modular turbine designs are also necessary because all roadways have weight restrictions. A fully assembled nacelle of 2.5-MW nameplate could easily exceed any allowable highway load limit.
To get our arms around the assembly subject, let’s start in the shop. The advanced technology in wind turbines depends a lot on conventional manufacturing techniques, such as welding, often used to assemble a tower. One welding-machine manufacturer recently called on a linear motion and assembly-technology company to help build custom welding machines for the wind industry. Such welding equipment builds 45-m long turbine-tower sections. Typically, a machine rolls a metal plate into a cylinder called a can that measures some 9-ft long by 8 to 15-ft dia. Another machine then welds along longitudinal seams to complete the can and then circumferentially to join cans.
“Can” welders are usually suspended from a guide rail for outside welding. Most of the machine is stationary while a weld head moves short distances on two and three axes, both along and across the seam. A linear control actuator at the end of a horizontal arm determines the motion of the weld head.
Assembling gearboxes give some scale to the tasks. The physical sizes of a gearbox and carrier components range from 4-ft cubes to one 12 ft on a side. When assembling hydraulic equipment to gearboxes and cylinders, color coding fittings help prevent assembly errors on a shop floor, and potentially catastrophic failures on a system in service.
Even a simple pin can assist assemblies. One in particular is a semi-permanent quick locking device that speeds assembly work by replacing other labor intensive fastening combinations such as a clevis pin and cotter pin, a pin and retaining ring, or a nut and bolt.
Filed Under: Turbines