JPS6130953A - Linear induction motor - Google Patents

Abstract

PURPOSE:To prevent the propulsion force from decreasing at high speed moving time by varying a gap between the pole surface of a stator and the secondary conductor at both ends of a stator, thereby reducing the influence of the end effect. CONSTITUTION:A stator 1' has a height equal to poles 3 at the center, the pole surface is flat, and a gap to the secondary conductor 6 is uniform. The height of the pole 3 of the stator 1' becomes gradually lower toward the both ends in the moving direction of the stator 1', and the pole surface 4' is inclined, and a gap 8 between the pole surface 4' and the conductor 6 gradually increases toward the both ends. With this configuration, the space changes of a magnetic field at both ends of the stator 1' become smooth.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a linear inductance motor, and more particularly to a linear inductance motor in which the influence of end effects is reduced by changing the shape of the stator poles.

Prior art and its problems Linear induction motors, unlike rotating machines, use a stator 1 with a finite length, so the magnetic field is always fixed when the motor is stationary.
The magnetic flux in the secondary conductor 6 becomes discontinuous, and a phenomenon called an electrical end effect occurs, resulting in a decrease in efficiency.

Conventionally, the stator 1 of a linear induction motor has a third
As shown in the figure, a single-phase or multi-phase fill is wound around a pole 3, which is made up of a number of laminated comb-like iron plates with slots 2 at an appropriate pitch, and the height of each pole is It was the same over the entire length, the pole surfaces 4 were lined up on the same plane, and the gap with the secondary conductor 6 was also uniform. Therefore, the magnetic field generated by this stator 1 is constant at the center, but changes at a steep angle at both ends, as shown in Figure 4, and the influence of the above-mentioned end effect is noticeable. there were.

Therefore, the efficiency of conventional linear injection motors is low, and the end effect appears particularly when the moving speed is high, that is, when the slip is small, and the propulsive force corresponding to the torque of a rotating machine is reduced.

This invention was made to eliminate the above-mentioned drawbacks of conventional linear inductor silanic motors, and has a simple configuration that reduces discontinuous changes in the magnetic field at both ends of the stator. The purpose of the present invention is to provide a linear induction motor that can be operated efficiently.

Structure of the Invention This invention lowers the height of the pole at both ends of the stator of a linear induction motor in the direction of movement, and also creates a predetermined slope on the pole surface to reduce the gap with the secondary conductor at the center. This feature is characterized in that discontinuities in the magnetic field at the ends of the stator are reduced by gradually widening the gap at the end of the stator.

Examples Examples of this invention! This will be explained with reference to Figures 1 and 2.

In the stator 1'', the height of each pole 3 is equal in the center part, and the pole surface is flat, and the gap with the secondary conductor 6 is uniform, and the height of the pole 3 of this stator 1'' is The pole 9 is made lower in the direction of movement of the stator 1' toward both ends, and the pole surface 4' is also inclined.

Therefore, the gap 8 between the pole surface 4' and the secondary conductor 6 gradually increases toward both ends. With this configuration, as shown in FIG. 2, the spatial variation of the magnetic field at both ends of the stator 1 becomes smooth, and the end effect caused by the discontinuity of the magnetic field described above can be suppressed. The linear induction motor can be operated efficiently and a reduction in propulsive force can be prevented.

Effects of the Invention As mentioned above, this invention can reduce the influence of the end effect by changing the gap between the pole surface of the stator and the secondary conductor at both ends of the stator, thereby reducing the propulsion force during high-speed movement. Deterioration can be prevented.

This enables high-speed operation, which is an inherent feature of linear induction motors, and also improves the efficiency of linear induction motors.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the present invention, Fig. 2 is a graph showing the magnetic field of a stator according to an embodiment of the invention, Fig. 3 is a side view showing a conventional example, and Fig. wk4 is a conventional example. It is a graph showing the magnetic field at both ends of . 1... Stator, 2... Slot, 3... Pole,
4...Pole surface, 5...Rotor, 6...Secondary conductor, 7...Iron rail, butt...Gap, 9...Pole length.

Claims (1)

[Claims] (1) At both ends of the stator of the linear induction motor in the moving direction, the height of this pole is gradually lowered, and the pole surface is sloped to a certain degree, so that the gap with the secondary conductor is reduced to the gap at the center. A linear induction motor characterized by a linear induction motor that is designed to be sequentially larger than .