VARIABLE SPEED DRIVE

摘要

An eddy current drive (711) has an electromagnet (15, 17) and an armature (19). Either one of the electromagnet or the armature is coupled to a motor shaft (31) so as to rotate therewith, while the other is coupled to a load portion (21). The motor can rotate at a continuous speed, while the speed of the load portion can vary by varying the energization of the electromagnet, so as to vary the coupling between the electromagnet and the armature. In one embodiment, the electromagnet is energized by way of inductive coils (217, 219). The coils provide a rotary coupling. In another embodiment, an electrical generator (713) is provided. The rotation of the motor shaft (31) generates electrical current that is used to energize the electromagnet. The amount of the electrical current that is provided to the electromagnet can be varied to vary the output speed of the load portion.