SU758408A1 - Two-speed synchronous electric motor - Google Patents

Description

(54) TWO-SPEED SYNCHRONOUS ELECTRIC MOTOR

one

The invention relates to electric machines, namely to two-speed synchronous electric motors with excitation from permanent magnets.

The design of a synchronous motor with excitation from a single permanent magnet, which is stationary on a shaft with a starting device in the form of a package with a short-circuited winding 1, is known.

The disadvantage of such electric motors is the impossibility of providing them with two different rotational frequencies.

A two-speed synchronous motor 2 is known. Two permanent magnets with different numbers of poles are inserted into the stator bore, between which there is a package with a short-circuited winding, with the stator winding being pole-switched. Since both magnets are located inside the stator package, when the stator winding is switched on according to one of the two possible connection circuits, a synchronous moment is created by that of two permanent magnets, the number of poles of which is equal to the number of poles created by the stator winding. The second permanent magnet, located in the stator bore, with

this does not perform useful work (i.e. is "ballast").

The disadvantages of this electric motor are high specific consumption of materials due to the increased consumption of expensive active material - a permanent magnet (since one of two permanent magnets works at each of the two rotational frequencies, and the other is "ballast"; low efficiency due to the fact that the part of the active materials

10, the stator, which is located above an idle ("ballast) magnet, does not perform useful work, but is a source of unavoidable losses.

The aim of the invention is to reduce the specific material consumption of an electric motor and increase its efficiency.

This goal is achieved by the fact that in a two-speed synchronous motor containing a stator with a pole-switched winding, the pole numbers of which are 2 and 6, and a rotor with a composite permanent magnet, the composite permanent magnet is designed to be partitioned, for which one part is made a central bipolar magnet fixed to the shaft in the form of a ring with two opposite segments cut off equidistant from the rotor axis, the magnetic axis of which is perpendicular to the rotor axis, and the second l is made of two clamped segment magnets with unidirectional magnetization along the base of the segments mounted on both sides of the central magnet with the possibility of longitudinal shear along the shaft with subsequent rotation around the rotor axis by 180 °.

FIG. 1 shows the construction of a two-speed synchronous motor; in fig. 2 and 3 - magnetic system.

The electric motor contains a stator pack 2 installed in the housing with a pole-switching winding 3, which, with one switch-on, creates a two-pole rotating field, and with another switch-on, creates a six-pole rotating field. On the rotor shaft 4 there is a starting element in the form of a package 5 with a squirrel cage 6, next to which is mounted a central bipolar magnet 7 on the rotor shaft, the magnetic axis of which is perpendicular to the axis of the shaft 4. The magnet 7 has the shape of a ring with two opposite segments cut off, equidistant from the rotor axis. The rotor is installed in the supports 8 and 9, placed in the slots of the support shields 10 and 11. On the shaft 4 of the rotor is also installed with the ability to move the collar 12, which is kept from spontaneous displacement along the shaft by means of a fixing ball 13, pressed by the spring 14.

Two permanent magnets 15 and 16, made in the form of segments, are attached to the collar 12. Both segments 15 and 16 have unidirectional magnetization along the bases of the segments (the south poles of the permanent magnets 15 and 16 are located in Fig. 2 from the top, and the north poles from the bottom). The space between the segment magnets 15 and 16 corresponds to the width of the magnet 8. When putting the collar 12 onto the shaft 4 in the position shown in FIG. 2, the coupling of the permanent magnets takes place, providing the six-pole structure of the magnetic system (see Fig. 3a).

If the collar 12 is rotated 180 ° with respect to the axis of the shaft 4 (compared to the position shown in Fig. 2) when mounted on the shaft 4, the north poles of the segment magnets 15 and 16 will be on top and the south poles from below, so that a bipolar structure of the magnetic system is provided (see FIG. 36).

The magnetic system shown in FIG. It interacts with the pole-shaped stator field, and the magnetic system shown in FIG. 36, - with a bipolar stator field.

Due to this, operation at two different rotational frequencies becomes possible: the bipolar inclusion of the stator winding should correspond to a bipolar structure of the magnetic system of the rotor (see Fig. 36), and a 6-pole structure of the magnetic system of the rotor (see Fig. 3a). In this case, the specific consumption of materials decreases, since for each of the two different rotational frequencies the entire volume of the permanent magnet (i.e., the central magnet 7 and both segment magnets 15 and 16) works. In addition, the efficiency increases as a result of the reduction in the axial length of the stator packet 2 as compared with the protetein by the length of one of the permanent magnets of the prototype (since there is no heat loss in the saved stator core).

Claims (2)

1. Lodochnikov M. A., Yuferov F. N. Microelectric motors for an automation system, M., Energii, p. 157, 1969. 2. USSR author's certificate No. 201522, H 02 K 19/00, 1955.