Once the yaw ring is installed, the nacelle main frame must be turned over in order to complete the yaw system assembly. Temporary legs are installed, and fixtures are added to the yaw ring.
The main frame is lifted, and one side is let down while the frame is rotated.
Here you can see the mounts for the yaw motors, and the bores for the yaw brake pistons.
Next, the frame is leveled and set on pads for the next phase of assembly.
The yaw reduction gearboxes are prepared and installed.
Spinning the reduction gear shaft rotates the housing to line up the mounting holes.
The mounting bolts are installed, run in, and torqued.
Once the yaw motors are installed, the system is ready for wiring.
Brake cylinder sleeves are installed in their bores, and the brake pistons are lubed before being placed in the sleeves.
The brake pads run directly on this machined surface on the yaw gear.
The tops of the brake assembly are bolted in, and torqued, then index marks are applied.
Next, the brake hydraulic tubing is installed, along with plastic cups to contain any fluid leakage through the vents.
Once assembled, the yaw drives and brakes are run and tested to ensure proper operation.
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