GB875059A - Improvements in and relating to electric fans - Google Patents

Abstract

875,059. Fan motors. GENERAL MOTORS CORPORATION. May 9, 1960 [May 28, 1959], No. 16236/60. Class 35. [Also in Group XXVI] A shaded pole fan motor comprises a stator surrounded by a squirrel-cage rotor which has two sets of fan blades on its periphery separated by a radial wall 12w, one set 12# effecting air circulation in a room or electric machine and the other smaller set 12m cooling the motor internally. The blades 12f and 12m are cast integrally with an annular cup-shaped body 12b which is secured to the shaft 12s by a hub 12h. The fan carries balance weights secured in grooves 12g. The casting may be of aluminium or a synthetic resin such as a phenolic resin (Fig. 2a, not shown). A laminated rotor assembly 12a, slotted to receive a squirrel-cage winding 12c interconnected by end rings which include balance weights 12z, is press-fitted into a recess 12r in the body 12b. The fan is mounted on an end plate which is fixed to a wall W by bolts projecting through apertures 17 in the plate. Conductors C are fed through the wall and an aperture 17w in the end plate to the stator windings. Air inlets 16i are provided in the plate so that air can be circulated around the interior of the motor and expelled through the gap G by the fan 12m. The stator core 14c is press-fitted on a sleeve 14s and, as shown in Fig. 5, has concentric coil pairs 44c and shading rings 44s. In an alternative arrangement (Fig. 6, not shown) only the inner coils 44c are used and the shading coils are continuously wound with them and subsequently short-circuited. The slot T housing the inner windings is sealed by magnetic wedges 44t. One end of sleeve 14s is press-fitted into a flange 16f of the end plate 16. A pair of bearing members 14b made of sintered metal or cast aluminium are coaxially aligned with the sleeve by radial legs 14r which are press-fitted into the sleeve 14s. A pair of shielding discs 14z are fitted to the bearings. The hub 12h of the rotor abuts shims 18w which are urged against a disc member 14z, whilst shims 18w retained by a snap ring 18 prevent axial movement of the sleeve &c. The sleeve is filled with a fibrous lubricant which can be replaced through a removable plug in the shielding discs. A fan 12x for circulating air to the condenser unit of an air conditioner is also provided.