SU817866A1 - Synchronous electric motor pole piece - Google Patents

Description

(54) SYNCHRONOUS MOTOR POLE

one

The invention relates to electrical engineering and relates to high-power, frequently-adjustable low-speed synchronous motors (the moment on the shaft is more than 300 m, the rotation frequency is 9-20 rpm, the circumferential speed at the periphery of the rotor is not more than 10 m / s.).

Such motors are powered by low-frequency converters, which provides not only low-frequency rotation, but also a smooth frequency start, which, unlike conventional asynchronous, eliminates the occurrence of additional dynamic loads on the rotor during its acceleration.

In addition, the voltage curve supplied to the motor contains a series of higher harmonic, resulting in an asynchronous magnetic field and corresponding additional moments and losses in the air gap between the stator and the rotor.

For shielding the higher harmonic fields in the air gap, low-speed synchronous motors use a damping system.

A synchronous electric motor is known, in which the damper winding rods are located in the grooves of the pole shoe and are connected within each pole by short-circuiting segments, and between poles by bridges or by crossing the segments of the adjacent poles.

The damper winding simultaneously performs the function of the starting winding during an asynchronous start.

Powerful frequency-controlled low-speed synchronous motors use synchronous start-up, which is carried out by gradually increasing the frequency of the applied voltage 1.

In this case, the damper winding serves only as a device that shields the highest harmonic magnetic fields in the air gap. Placing the damper winding on the pole bagmack requires an increase in the height of the shoe 1.5-2.0 times compared with the height of the shoe in the absence of this winding, which leads to a corresponding increase in the scattering flux.

The purpose of the invention is to reduce the weight and dimensions of a pole, by reducing the scattering flux.

This goal is achieved by the fact that in the pole of a synchronous electric motor containing a laminated core with a pole shoe on which a damper system is installed, the latter is made in the form of a nonmagnetic electrically conductive screen located on the surface of the pole shoe and encompasses its tangentially protruding parts and copper sheets, placed along the length of the pole between the sheets of the core, and the screen and the copper sheets are electrically connected by means of flexible jumpers.

To fix the screen in a tangential direction, the ends of the screen can be bent and arranged in grooves made in the core sheets.

Grooves can be made in the screen and in the core sheets to accommodate flexible webs.

FIG. 1 depicts a pole in isometric projection; in fig. 2 - groove for fastening the screen to the copper sheet; in fig. 3 shows section A-A in FIG. 2

The pole contains laminated core 1, made of sheets of steel. Along the length of the core between the sheets of the core there are several copper sheets 2.

The shoe 3 poles is covered by a trough-shaped screen 4 made of a non-magnetic material with a low electrical resistivity, for example copper.

In the axial direction, the screen 4 is bent on the shoe 3, and in the tangential direction, the detached end parts 5 of the screen 4 are installed in the slots 6 in the radial direction extruded in the sheets 1 of the radial direction the screen is pressed to the surfaces of the 7-pole shoes by 3 pressing forces and centrifugal forces of the coils 8 poles . The screen 4 is electrically connected to the copper sheets 2 by means of flexible jumpers 9.

Each jumper 9 with one end is attached to the screen 4 through a groove 10, made in the screen in the area of the copper sheet 2. The other end of the jumper is attached to the copper sheet 2.

To accommodate the jumpers 9 in the area of the copper sheets 2, the grooves 11 are made in the sheets of the core 1.

For electrical connection with screens of other poles, screen 4 is provided with jumpers 12, which can be stamped together with screen 4 or soldered to it.

The proposed pole design makes it possible to reduce by 1.5-2 times the height of a pole bashmak in comparison with the known device and, therefore, significantly reduce the scattering flux of the pole system.

The latter, in turn, allows to reduce the size and weight of the machine, or in the same dimensions to get more power.

In addition, the proposed device is more technologically and reliably than the usual full damper system, since it eliminates punching grooves in pole shoes, pressing and sealing rods in these grooves, soldering rods to short-circuiting segments that must pass the full current of damping rods.

Claims (3)

1. A pole of a synchronous electric motor containing a laminated core with a pole shoe on which a damper system is installed, characterized in that, in order to reduce weight and dimensions, the damper system is made in the form of a nonmagnetic electrically conductive screen located on the surface of the pole shoe and covering it tangentially protruding parts, and copper sheets placed along the length of the pole between the sheets of the core, and the screen and the copper sheets are electrically connected by means of flexible jumpers. 2. A pole according to claim 1, characterized in that the end portions of the screen are bent and arranged in slots made in the core sheets. 3.Pole on PP. 1 and 2, characterized in that grooves for accommodating flexible jumpers are provided in the shield and in the cores of the core. Sources of information taken into account during the examination 1. Alekseev A.Ye. Design of electrical machines. L., SEI, 1968, p. 165-166. Vug 7 A-A (rig. 3