JPH0510904B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a DC machine, and more particularly to a stator structure for improving the rectification characteristics of a large DC motor used in a rolling mill or the like.

[Conventional technology]

DC machines have long had the phenomenon of non-sparking band movement, where the position of the non-sparking band moves to the de-excited side as the rotational speed increases.As a countermeasure to this, it is necessary to adjust the interpolation shunt current according to the rotational speed. method, and a method of adjusting the interpole magnetic flux using a separate power source. However, these systems are expensive because they require a rectification compensation device to be added in addition to the DC machine main body. Therefore, the inventors of the present invention have proposed a solution shown in Japanese Patent Application Laid-Open No. 62-71463, which can be solved by simply modifying the internal structure of the DC machine body.

This method will be explained with reference to FIGS. 4 to 7.

Figure 4 is an exploded view of the main parts of the DC machine. A main pole 2 and a complementary pole 3 are provided on the inner periphery of the yoke 1. The main pole 2 includes a main pole iron core 4, a magnetic pole piece 4A, and a field winding 5.
It serves to provide main magnetic flux to the armature winding 7 of the armature 6 rotating inside the stator 12,
The commutator 3 is formed from a commutator iron core 8 and a commutator winding 9, and serves to provide a commutator magnetic flux to generate a rectified electromotive force during a rectification phenomenon in which the current flowing through the armature winding 7 is reversed. There is. Further, between the main pole 2 and the commutator pole 3, there are short-circuit cores 10, 10 that short-circuit the side surface of the commutator core 8 near the armature 6 side and the side surface of the magnetic pole piece 4A.
A and 10B are provided.

The operation of a DC machine with such a configuration during low-speed operation and high-speed operation is shown in FIGS. 5A and 5B. In these figures, φ _MP , φ _MP1 , φ _MP2 are the main magnetic flux,
φ _IP , φ _IP1 to φ _IP3 are interpolation magnetic fluxes, and φ _IA , φ _IA1 , φ _IA2 are commutating magnetic fluxes for rectification compensation. During low-speed operation in Figure A, the main magnetic flux φ _MP1 increases due to the strong field, and the magnetic flux density between the main pole iron core 4 and the yoke 1 is high, resulting in a magnetically saturated state. The leakage commutating magnetic flux leaking through is only φ _IP1 , and the remaining φ _IP2 and φ _IP3 become commutating compensating magnetic flux φ _IA1 for entering the armature 6 side and generating a rectifying electromotive force.

In addition, during high-speed operation in Figure B, the field is weakened, so the main magnetic flux φ _MP2 is small, and the magnetic flux density between the main pole iron core 4 and the yoke 1 is low, resulting in a state where it is not magnetically saturated. Therefore, the commutating magnetic flux φ _IP tends to leak to the main pole iron core 4 via the short-circuited iron core 10B, and the commutating magnetic fluxes φ _IP1 and φ _IP2 become the leaking commutating magnetic flux to the main pole iron core 4,
The commutating magnetic flux φ _IP3 enters the armature 6 and becomes the commutating magnetic flux φ _IA2 for commutation compensation. In this manner, the amount of commutating magnetic flux for rectification compensation incident on the armature 6 is smaller during high-speed operation than during low-speed operation, so that movement and development of the non-spark zone can be prevented.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, no consideration is given to what kind of magnetic material to use as the short-circuiting iron core. When used as an iron core, it was found that there was a problem in that sparks were generated from the brushes when the load current suddenly changed during transient operation. This is particularly problematic when applied to a so-called four-quadrant DC machine that performs forward/reverse rotation, power running, and regenerative braking operation, since sudden changes in load current occur frequently.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, to prevent the no-spark band movement phenomenon by simply modifying the internal structure of the DC machine body, and to prevent the generation of sparks from the brush in any operating condition. We are able to provide DC machines that can.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a magnetic flux change suppressing member that generates an eddy current due to a sudden change in the leakage magnetic flux of the magnetic flux in at least a part of the flow path of the leakage magnetic flux of the magnetic flux that passes through the short-circuited core. It is characterized by having been established.

[Effect]

The magnetic flux change suppressing member provided in the flow path of the leakage magnetic flux of the magnetic pole via the short-circuited core generates an eddy current so as to suppress the change of the leakage magnetic flux of the magnetic pole in response to a sudden change in the load current. Therefore, it is possible to secure the interpolation magnetic flux for obtaining a good rectification state when the load current suddenly changes, and therefore it is possible to prevent the generation of sparks from the brush.

〔Example〕

Prior to explaining the embodiments of the present invention, the results of the investigation by the present inventors regarding the reason why sparks are generated from the brush in the conventional device when the load current suddenly changes are shown in Figs. 6A to 7C. This will be briefly explained using

FIG. 6A is a characteristic diagram in which time is plotted on the horizontal axis and changes in load current are plotted on the vertical axis. In a DC machine operated in four quadrants, the load current rapidly increases, reaches a steady state, and then rapidly decreases (current changes in the negative direction are not shown).
Figure B is an exploded view of the main parts of the DC machine, showing the operation during low-speed operation when the load current increases rapidly. During low-speed operation shown in the figure, the main magnetic flux φ _MP1 is large due to the strong field, and φ _IP1 of the interpole magnetic flux φ _IP passes through the short-circuited iron core 10B to the main pole iron 4 as in the conventional case.
leakage to the magnetic flux, resulting in leakage commutating magnetic flux. Figure C is a characteristic diagram showing the armature reaction magnetomotive force, which is maximum at the center of the commutating pole. Therefore, in Figure B, the commutating magnetic flux φ _IP3 at the time of a sudden increase in the load current is due to the fact that the commutating pole air gap length is larger than the main pole air gap length and that the armature reaction magnetomotive force acts strongly on the commutating pole. , it is difficult to directly enter the armature 6 from the commutator core 8 and become a commutator magnetic flux for rectification compensation, and the main pole core 4 passes through the short-circuit core 10A.
leaks to the magnetic flux, resulting in leakage commutating magnetic flux. As a result, the commutating magnetic flux that enters the armature 6 side to generate a rectified electromotive force becomes only φ _IP2 , and the commutating compensating magnetic flux φ _IA1 becomes small.

Figure 7 is a characteristic diagram showing the load current on the horizontal axis and the commutating pole magnetic flux φ _IA for rectification compensation on the vertical axis. Polar magnetic flux decreases. The same holds true when the load current suddenly decreases and during high-speed operation. From this, it has been found that during transient operation, leakage commutating magnetic flux increases in response to changes in load current, commutating compensating commutating flux decreases, and a problem occurs in which sparks are generated from the brush.

The present invention will now be described based on the embodiments shown in FIGS. 1A and 3B. FIGS. 1A and 1B are an exploded view of main parts and a partial perspective view of a short-circuit core portion of a DC machine according to an embodiment of the present invention. In each figure, parts that are the same or equivalent to those of the conventional one are given the same reference numerals, and explanations thereof will be omitted. Short-circuit cores 10, 10 made of laminated iron plates 13 are installed on the side surface of the commutating pole core 8 near the armature 6 side.
A, 10B are provided, and magnetic flux change suppressing members 11, 11A, 11B made of a block iron core 14 are provided on the side surface of the short-circuited iron core 10 on the main pole iron core 4 side. As shown in FIG.
B generates an eddy current IC in the direction of suppressing the change in the leakage interpolation magnetic flux φ _IP1 in the direction of the arrow.

With this configuration, when the load current increases rapidly as shown in Figure 2 A, the main pole magnetic flux φ _MP and the interpolation magnetic flux φ _IP change as shown in Figure 2 B during low-speed operation, and as shown in Figure 2 C during high-speed operation. Each works as follows. That is, during low-speed operation, the main magnetic flux φ _MP1 becomes large due to the strong field, and the magnetic flux density between the main pole iron core 4 and the yoke 1 is high and magnetically saturated, so that the magnetic flux is The leakage commutator magnetic flux is only φ _PI1 as in the conventional case. On the other hand, the leakage commutator magnetic flux that increases rapidly with the sudden increase in load current and tries to leak to the main pole core 4 through the short-circuit core 10A is suppressed by the eddy current generated in the magnetic flux change suppressing member 11A, so the leakage commutator flux The commutating magnetic fluxes φ _{IP2 and} φ _IP3 other than the magnetic flux φ IP1 become the commutating magnetic flux φ _IA1 for commutation compensation which is incident on the armature 6 side and generates a rectifying electromotive force.

In addition, during high-speed operation, the field is weakened, so the main magnetic flux φ _MP2 becomes small, and the magnetic flux density between the main pole iron core 4 and the yoke 1 is low and is not magnetically saturated, so the short-circuited iron core The leakage interpolation magnetic fluxes leaking through 10B are φ _IP1 and φ _IP2 as in the conventional case. on the other hand,
The leakage commutator magnetic flux that increases rapidly as the load current increases and tries to leak to the main pole core 4 through the short-circuit core 10A is suppressed by the eddy current generated in the magnetic flux change suppressing member 11A, so that the leakage commutator flux φ _IP1 ,φ _IP2
The remaining commutating magnetic flux φ _{IP3 excluding the commutating magnetic flux φ IP3} enters the armature 6 side and becomes commutating magnetic flux φ _IA2 for commutation compensation.

In this way, the amount of magnetic flux incident on the armature 6 side becomes smaller during high-speed operation than during low-speed operation, so
The movement of the no-spark zone can be prevented only by using the DC machine itself. In addition, the block iron core 11 generates eddy current in response to sudden changes in load current and suppresses changes in leakage commutating magnetic flux, so that sufficient commutating flux for commutation compensation can be ensured even when load current suddenly changes. .

FIG. 3 is a characteristic diagram showing the load current on the horizontal axis and the commutating pole magnetic flux φ _IA for commutation compensation during steady operation and transient operation on the vertical axis. As is clear from the figure, commutating magnetic flux for rectification compensation during transient operation when the load current changes suddenly can be obtained almost in the same way as during steady operation, which is effective in preventing brush sparks during transient operation. .

In the above embodiment, an example was described in which the laminated core 13 is used as the short-circuit core 10 and the magnetic flux change suppressing member 11 made of the lumpy core 14 is provided on the side surface of the laminated core 13 on the side of the main pole core 4. However, the magnetic flux change suppressing member 11
is provided on the side surface of the short-circuit core 10 on the side of the commutating pole core 8, or a block core is used as the short-circuit core 10, and this is also used as the block core of the magnetic flux change suppressing member 11, or a block core is used as the magnetic flux change suppressing member 11. 14, a similar effect can be obtained by providing a short-circuiting layer that short-circuits between the iron plates in a part of the short-circuiting iron core 10 made of the laminated iron plates 13.

〔Effect of the invention〕

As described above, according to the present invention, a magnetic flux change suppressing member that generates an eddy current due to a sudden change in the leakage magnetic flux of the magnetic flux is provided in at least a part of the flow path of the leakage magnetic flux of the magnetic flux that passes through the short-circuited core. Therefore, the eddy current generated in this member can suppress changes in the leakage commutator magnetic flux in response to sudden changes in load current, secure the necessary commutator compensator flux, and prevent sparks from the brush during transient operation. Occurrence can be prevented.

[Brief explanation of the drawing]

Figures 1A and 1B are an exploded view of main parts and a perspective view of a short-circuit core part of a DC machine according to an embodiment of the present invention,
Figure A is a characteristic diagram of the load current, Figure 2 B and C are explanatory diagrams of the operation of the DC machine shown in Figure 1 A during low-speed operation and high-speed operation, and Figure 3 is the DC current shown in Figure 1 A. Characteristic diagram showing the relationship between machine load current and interpolation magnetic flux, No. 4
The figure is an exploded view of the main parts of a conventional DC machine, Figure 5 A and B are explanatory diagrams of the operation of the DC machine shown in Figure 4 during low-speed operation and high-speed operation, and Figure 6 A is the load current during operation. Figure 6 (b) is an explanatory diagram of the operation of the DC machine shown in Figure 4 when the load current suddenly changes, Figure 6 (c) is a characteristic diagram of the armature reaction magnetomotive force, and Figure 7 is a diagram of the operation of the DC machine shown in Figure 4. FIG. 3 is a characteristic diagram showing the relationship between load current and interpolation magnetic flux. 1... Yoke, 2... Main pole, 3... Complementary pole, 4...
Main pole iron core, 5... Field winding, 6... Armature, 7...
...Armature winding, 8...Commuting pole core, 9...Commuting pole winding, 10...Short circuit core, 11...Lump core.

Claims (1)

[Claims] 1. A DC machine including an armature 6 and a stator 12, wherein the armature 6 is provided with an armature winding 7, and the stator 1 is provided with an armature winding 7.
The stator 12 includes a yoke 1, a plurality of main poles 2, a plurality of commutating poles 3, a short-circuit core 10, and a magnetic flux change suppressing member 11. The main pole 2 includes a main pole iron core 4 and a field winding 5, and is attached to the inner peripheral side of the yoke 1, and the commutating pole 3 includes a commutating pole iron core 8 and a commutating pole. The short-circuit core 10 is provided with a field winding between the main pole core 4 and the commutating pole core 8. 5 and the commutator winding 9 toward the armature 6 side, extending substantially in the circumferential direction to allow leakage commutator magnetic flux to flow. A direct current is provided in at least a part of the flow path of the leakage magnetic flux of the leakage magnetic pole, and generates an eddy current due to a sudden change in the magnetic flux of the leakage magnetic pole, thereby suppressing a sudden change in the magnetic flux of the leakage magnetic pole. Machine. 2. The DC machine according to claim 1, wherein the short-circuit core 10 is composed of a laminated iron plate 13, and the magnetic flux change suppressing member 11 is composed of a block core 14. 3. The DC machine according to claim 1, wherein the short-circuit core 10 is made of a block core and also serves as the magnetic flux change suppressing member 11.