NOVELTY - The accessory has a wrap spring (56) between two rotary clutch portions. An actuator input is moved along the rotary axis of one clutch portion to drivingly engage the same clutch portion such that the spring uncoils against the interior clutch surface of the same clutch portion and transmit rotary power between clutch portions. The axial end face (180) of the wire forming one end (140) of the spring contacts the abutment surface of the other clutch portion to transmit the rotary power from the spring to the other clutch portion.    USE - Driven accessory for use in motor vehicle, as well as hybrid vehicle or electric vehicle. Can be used in driving engine accessory e.g. fan, alternator, generator, starter-alternator or starter-generator for producing electricity, water pump, power steering pump, hydraulic pump, vacuum pump, or air compressor, blower, supercharger, power take-off, or any accessory driven by other power sources such as electrically-powered or fluid-powered motors.    ADVANTAGE - The wrap spring is kept engaged with the interior clutch surface to continue transmitting rotary power through the clutch assembly, omitting need for the coil assembly to be powered without halting transmission of rotary power. Since the clutch assembly can be operated with very little power and can be cycled quickly, the accessory portion can be operated in pulse-width modulated manner. The clutch assembly can also be operated in pulsed manner such that the accessory, such as the air conditioning compressor, can be operated at the same time with relatively low displacement, reducing power consumption and maximizing duration of the accessory operation for given state of battery charge in an electric or hybrid vehicle.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method of operating a driven accessory.    DESCRIPTION OF DRAWING(S) - The drawing shows the enlarged perspective view of a wrap spring.    Wrap spring (56)    One end of wrap spring (140)    Helical coils (142)    Other end of wrap spring (144)    Axial end face (180)