Abstract: Modular electrical apparatus is provided which comprises a plurality of customer removable electrical devices 22 inserted in one end of a drawer type tubular chassis 10 and various field replaceable support units 44,46 mounted at the other end of the chassis. The devices and support units are all blind pluggable into a removable central electrical distribution unit which includes complementary connectors 52,54,56 on opposite sides and a set of electrical conductors for connecting the devices and units. Internal electrical connection of all the units in the drawer is via the electrical distribution unit and external electrical connection is made only to the outer end of the support units. Cooling fans for inducing an air flow through the tubular chassis to cool the devices and support units are mounted in the central electrical distribution unit. All the components can be removed for repair or replacement from either the front or rear entrance of the tubular chassis.

Abstract: Electrical apparatus is described which may include one or more electrical devices, each being located in a corresponding one of a plurality of device positions defined in a first section of a housing. The system further includes at least one dual side entry brushless dc motor driven centrifugal fan positioned such that each side entry is opposite a device position, and a power supply unit. In operation, the fans provide forced air cooling of the devices and power supply. Each of the devices is selected from a plurality of possible device types, each device type presenting a different impedance to the flow of cooling air.

Abstract: A disk file comprises a disk stack subassembly and a head positioning actuator each mounted on opposite sides of a central box frame. The disk stack subassembly has a non-rotating central spindle and an in-hub electric motor whose stator is mounted on the spindle. The rotor of the motor is mounted internally of a hub supported for rotation about the spindle by two bearings at opposite ends of the spindle. A stack of disks is mounted externally on the hub. The box frame is open to one side and the opposite ends of the stationary spindle are located and fixed in the frame so that the disk stack subassembly spans the open side. Because of the symmetry and rigidity of the design, susceptibility to thermal or vibration induced misregistration is reduced. Finally a cover completes the enclosure.