GB526896A - Improvements relating to dynamo-electric machines - Google Patents

Abstract

526,896. Motors; rotary transformers. LIST, H. March 28, 1939, No. 9630. Convention date. March 31, 1938. [Class 35] A D.C. machine suitable for use as a small motor or a rotary transformer comprises a rotating permanent magnet, a wound stator with poles, and a stationary switching service for energizing the windings in turn by an eccentric or equivalent means actuated by rotation of the rotor. In the form shown in Figs. 1 and 3 the insulating plates 4, 6 carry respectively the ball and pivot bearings of the shaft of the bipolar magnet 8, and the plate 4 carries also the lateral shoe members 10 of three T-shaped poles 9 of a laminated stator having a common flux return path in the end member 3. The coils 11 are connected to three sets of normally separated spring contacts 13, which are mounted in extensions 12 of the plate 6 and are closed in turn by the outer ring 17 of a ball bearing operated by an eccentric part 16 on the shaft. The setting is such that one coil is not de-energized until the next ahead is energized. In an alternative form (Fig. 4, not shown) a permanent magnet is stationary and arranged axially within the three poles 9 and its field is completed by a radial sector-shaped permanent magnet on the shaft, rotation of which either strengthens or weakens the polarity of the three cores in turn. The sector preferably covers two of the poles and is made up to a complete disc by a non-magnetic filling. In Fig. 5, a form is shown in which the rotating magnet 8 is mounted in the bore of three radial stator poles 8', the coils 11 of which are energized by spring contacts 13 as in Figs. 1 and 3. A D.C. to A.C. converter shown in Fig. 8 has on the three poles 9 one set of coils 11, which, by means of eccentric-operated contacts, give the motor drive, and a second set 11a in which A.C. is induced. Another form is described in which the coils 11a are connected to terminals through a second set of spring contacts actuated by a second eccentric on the shaft so that the machine acts as a D.C. to D.C. converter taking supply, for example, from a 4-volt dry battery and giving direct current at 100 volts. It is stated that the machines will run continuously with a power consumption of 0À001 watt. Specification 526,930 is referred to.