wet-rated varieties. Types Many styles of ceiling fans have been developed over the years in response to several different factors such as growing energy-consumption consciousness and changes in decorating styles. The advent and evolution of new technologies have also played a major role in ceiling fan development. Following is a list of major ceiling fan styles and their defining characteristics: Cast-iron ceiling fans. These account for almost all ceiling fans made since their invention in 1882 through the mid-1960s. A cast-iron housing encases a very heavy-duty motor, usually of the shaded-pole variety. These motors are lubricated by means of a thrust bearing submerged in an oil-bath and must be oiled periodically, usually once or twice per year. Because these fans are so sturdily built, and due to their utter lack of electronic components, it is not uncommon to see cast-iron fans aged eighty years or more running strong and still in use today. The Hunter 'Original''' (manufactured by the Hunter Fan Co.) is by far the most recognizable example of a cast-iron ceiling fan today. It has enjoyed the longest production run of any fan in history, dating from 1906 to the present day. The Hunter Original employed a shaded-pole motor from its inception until 1984 (the 36" Original remained shaded pole before it was replaced with the 42" Original in 1985), at which point it was changed to a much more efficient permanent split-capacitor motor. Though the fan's physical appearance remains virtually unchanged, the motor was downgraded in 2002 when production was shipped to Taiwan; the motor, though still oil-lubricated, was switched to a "skeletal" design, as discussed below, with a shortened main shaft that inadvertently caused reliability issues. In 2015, this motor design was revised, and once again employs a full-length main shaft; the key element to the longevity of the pre-2002 motors. 20 pole Induction "Pancake" motor ceiling fans. These fans with highly efficient cast aluminum housings, were invented in 1957 by Crompton-Greaves, Ltd of India and were first imported into the United States in 1973 by Encon Industries. This Crompton-Greaves motor was developed through a joint venture with Crompton-Parkinson of England and took 20 years to perfect. It is considered the most energy-efficient motor ever manufactured for ceiling fans (apart from the DC motor) since it consumes less energy than a household incandescent light bulb. Stack-motor ceiling fans. In the late 1970s, due to rising energy