Patent GB-128195-A (GB)
Title: Magnetic Reduction Gear.
IPC: H02K49/06
Filed: 1919-05-14
Abstract: 128,195. Westinghouse Gear & Dynamometer Co., (Assignees of Kasley, A. T.). June 8, 1918, [Convention date]. Void [Published under Sect. 91 of the Act]. Electro-magnetic clutches.-A variable-speed power-transmitting apparatus which allows reversal of the direction of rotation of the driven shaft without reversing the rotation of the driving shaft comprises a rotating field magnet 6 coupled to the high-speed driving shaft 7, a stationary wound magnetic member 12, and an annular rotating member 63 with pole-pieces 15 which are mounted on the driven shaft 17 and serve to convey the flux from the magnet 6 to the stationary member 12. As shown, the field magnet has four poles 8, 9, 10, 11 which are excited by continuous current through slip-rings 30. The member 12 is fitted with two laminated rings having slots 41 in which two groups of windings 13, 14, termed secondaries, are located, one group being advanced ahead of the other to provide the necessary phase difference for starting. In the example shown, the angle of displacement is about 45 degrees. The pole-pieces 15 are laminated and are carried by a non-magnetic spider 16; ring laminµ 23 located adjacent the field magnet 6 are also carried by the spider 16. Three kinds of polepieces are employed; the pole-pieces a extend the entire width of the field magnet 6 while the pole-pieces b, c are of less than half this width. The pole-pieces are separated by wide and narrow spaces 25, 26 so that they in effect form two sets separated circumferentially by approximately 45 degrees, one set on one side of the cage cooperating with the secondary 13 and the set at the other side co-operating with the secondary 14; the pole-pieces a are included in both sets. As shown, each set includes sixteen pole-pieces and twelve wide spaces 25 giving the effect of a twenty-eight pole arrangement. Holes 27 in the laminµ 23 reduce magnetic leakage. Fig. 4 is a developed diagram of the windings designed for a speed reduction of eight to one or six to one depending on the direction of rotation. The secondaries each include two windings 35, 35<1> which are arranged to produce twenty-eight poles and may be connected together through switches 37, 38 and resistances 37<a>, 38<a>; when the switches are moved to reverse the connexions, the direction of rotation of the member 63 is reversed. One of the windings 35, 35<1> is preferably made heavier than the other and is located in wider slots in the laminae; by connecting the heavier winding to a source of continuous current 42 through a switch 43, the cage runs at synchronous speed. For lower speeds of the driven member, windings 36, 36<1> arranged in the slots of the stator 12 and windings 34, 34<1> surrounding the pole-pieces 15 are brought into action, these windings being each arranged for fourteen poles; continuous current is supplied to the windings 34, 34<1> from the source 42 and the switch 39 is opened. Reversal of rotation of the driven member 63 may be obtained by dividing the field magnet into two axial portions and reversing the direction of the current through one of them. In the case of a breakdown, the shafts 7, 17 may be directly coupled, for example, by means of a set-screw 51.