Multiple up-tower lifting appliances on wind turbines

1. 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 situated on top of, secured to and connecting the at least two longitudinal beams, the at least two longitudinal beams supporting the at least two transverse beams from below the at least two transverse 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.

2. The lift system of claim 1 , further comprising a third lifting appliance mounted in the nacelle on at least one of the main bearing housing securements, at least one of the gearbox pillow blocks, a dedicated mounting platform, a bedplate, a torque arm, a generator housing or any combination thereof.

3. The lift system of claim 1 , further comprising a third lifting appliance mounted on at least one of the gearbox pillow blocks.

4. The lift system of claim 1 , wherein the common support comprises:

a first pair of vertically oriented pillow block bridges secured to the gearbox pillow blocks and spaced apart transversely in the nacelle;

a first transverse beam secured to and connecting the first pair of the transversely spaced apart pillow block bridges;

at least one first support base for supporting at least one of the lifting appliances, the at least one first support base mounted on the first transverse beam;

a second pair of vertically oriented pillow block bridges secured to the gearbox pillow blocks and spaced apart transversely in the nacelle;

a second transverse beam secured to and connecting the second pair of the transversely spaced apart pillow block bridges; and,

at least one second support base for supporting at least one of the lifting appliances, the at least one second support base mounted on the second transverse beam.

5. The lift system of claim 4 , wherein the common support is mounted on the at least two gearbox pillow blocks and in at least two yaw drive pockets.

6. The lift system of claim 5 , further comprising at least two support pillars connected to the first or second transverse beam, the support pillars mounted in the yaw drive pockets.