GB191015587A - Improvements in or relating to Dynamo-electric Machinery. - Google Patents

Abstract

15,587. Holbech, R. H. June 29. Armatures and field-magnets, cooling and ventilating. -For cooling a high-speed alternator or other machine having revolving magnets, the rotor is provided with air spaces at the periphery and close to the shaft, both sets of which are parallel to the shaft and substantially concentric with the path of the flux, and which are used in combination with fans or other means for driving air through the machine. In the four-pole rotor shown in Fig. 1, the periphery is cut away at a and the centre is cut away at b, so as to form triangular ducts along the shaft c with curved sides approximately concentric with the portions exposed at a. The winding-grooves h are preferably radial to the cut-away parts, as shown, and the windings may be supported on cages g which are rigidly mounted on the shaft as shown in Fig. 9. Fans i may be used to force air through the ducts. In the two-pole rotor shown in Fig. 4, the central spaces b are semicircular, and complementary spaces may be formed in the shaft c, as shown in dotted lines. An external fan, a works or mill chimney, or other means may be used to propel the air, and the machine may be enclosed, as shown in Figs. 9 and 11, so as to expel the air through a central duct m, with or without side ducts k, after drawing it in through openings j, as shown by the arrows. In the form shown in Fig. 17, air enters at one end-belt p and duct j and leaves at the other, as well as from openings around the rotor. In the open type shown in Fig. 15, air enters through ducts and leaves through openings in the end bell p and stator body. When air enters at both ends, the fans are preferably curved, and the slip-rings are preferably enclosed to prevent dust from the brushes from being drawn into the machine.