In order to properly cook most food, it is frequently necessary to heat the food uniformly. When cooking a dish in microwave ovens, the ovens frequently overcook some portion of the dish while undercooking other portions due to non-uniform energy distribution.
When cooking with microwave ovens, food is placed in a microwave cavity in which microwaves injected into the cavity rebound from the walls of the cavity. This causes cold spots where the microwaves cancel one another and hot spots where the microwaves re-enforce one another. The location of the hot and cold spots differs between ovens. Furthermore, the location of the hot and cold spots changes with the nature of objects placed within microwave ovens so the change in the type of food placed in the ovens or the container holding the food will shift the hot and cold spots. Even if the person doing the cooking knows where hot spots are for a given portion of food within a given dish or container, this knowledge will not necessarily help once the food or container are changed. In order to cook food in a microwave oven one must absorb microwaves reflecting within the oven and therefore different foods having different dimensions will absorb some microwaves and not others.
Because of the aforementioned difficulties, commercially available microwave ovens usually have instructions suggesting that the food be turned at certain intervals. In order to avoid the inconvenience of manually turning food, some microwave ovens are currently available with built-in turntables to slowly rotate the food being cooked. However, there are numerous microwave ovens already being used which do not have turntables and many microwave ovens currently being manufactured which do not have turntables. Consequently, there is a great need for turntables which can be purchased as accessories so as to increase the usefulness of those microwave ovens already in existence and those now being manufactured which do not have built-in turntables.
In order to operate a turntable within a microwave oven, power must be delivered conveniently and safely to the turntable. According to prior art practices, this can be accomplished by a drive shaft which extends through a wall of the oven or perhaps by wires which extend through a wall of the oven. Retrofitting microwave ovens with drive shafts or wires for turntables is not advisable since microwaves could quite possibly leak through the openings for the drive shafts or wires and endanger people near the ovens. Consequently, there is a need for a self-contained power source which can fit into a microwave oven in order to drive a turntable within the oven without having to connect that turntable in some manner to an outside power supply.