Multiple up-tower lifting appliances on wind turbines

A nacelle-mounted multiple-appliance lift system, the lift system comprising:

• a first lifting appliance mounted in a nacelle of a wind turbine on both at least two main bearing housing securements and at least two gearbox pillow blocks;
• and,
• a second lifting appliance mounted in the nacelle of the wind turbine on both the at least two main bearing housing securements and the at least two gearbox pillow blocks,
• the first and second lifting appliances sharing both the at least two main bearing housing securements and the at least two gearbox pillow blocks,
• wherein the first and second lifting appliances are mounted on a common support mounted on both the at least two main bearing housing securements and the at least two gearbox pillow blocks, the common support bearing weight of both the first and second lifting appliances,
• wherein the common support comprises:
• at least two pillow block bridges secured to the at least two gearbox pillow blocks and spaced apart transversely in the nacelle;
• at least two main bearing supports secured to the at least two main bearing housing securements and spaced apart transversely in the nacelle;
• at least two longitudinal beams extending between and supported on the at least two main bearing supports and the at least two gearbox pillow blocks;
• at least two longitudinally spaced apart transverse beams secured to and connecting the at least two longitudinal beams, the at least two transverse beams situated longitudinally between the at least two pillow block bridges and the at least two main bearing supports;
• and,
• at least two support bases for supporting the lifting appliances, each of the at least two support bases mounted on at least one of the longitudinal beams or at least one of the transverse beams.