One prior art ceiling fan includes a pair of hanging fans, each comprising two or more fan blades. The two hanging fans are secured to a rotary disk, which is rotatably mounted on a central shaft secured to the ceiling. In operation, the two hanging fans are started to rotate when the switch is turned on. The reaction caused by the rotation of the two hanging fans forces the rotary disk to rotate about the central shaft. A conducting bushing is secured on the central shaft so that the bushing does not rotate when a support base, including conductors, is rotated with the disk. Electrical power is transmitted through the central axis to the conducting bushing, and then from the conducting bushing to the hanging fans through the conductors. A gear secured to the central axis engages a reduction gear mounted in a rotation retaining set secured on the rotary disk.
One significant disadvantage with that ceiling fan is that the rotation retaining set and support base, being mounted on the rotary disk, tend to cause the disk to wobble. Another disadvantage is that the entire hub of the fan rotates. Thus, a light mounted to the rotary disk would also rotate with the fans, and tend to create moving and disorienting light effects.