JPH0368628B2 - - Google Patents

Description

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

[Background of the invention]

It has been known for a long time that DC machines have a phenomenon in which the no-spark zone moves toward the over-rectified side as the rotation speed increases, and this does not pose a particular problem in small DC machines. In large DC machines, such as DC motors for rolling mills, brush sparks are generated due to this non-sparking zone moving development, so as a countermeasure, there is a method of adjusting the commutating pole shunt current according to the rotation speed. Alternatively, a method using a DC exciter has been proposed (Hitachi Review Vol. 51, No. 10, p. 1).

The former method will be explained with reference to FIGS. 3 and 4. In FIG. 3, 1 is a DC machine, and normally a load current I _M flows through an armature 2, a commutator winding 3, and a compensation winding 4. On the other hand, as shown in Fig. 4, in the DC machine 1 where the spark-free band position moves toward the over-rectification side as the rotational speed increases, unless some countermeasure is taken, the Brush sparks are generated from the point, making it impossible to achieve sparkless commutation. Therefore, as shown in FIG. 3, the rotation speed of the armature 2 is detected by a rotation detector 5, and the detection output is inputted to a contactor controller 6, which opens and closes the contactors 8A and 8B. A commutator shunt circuit connected between both ends of the commutator winding 3 and the compensation winding 4, that is, a commutator shunt circuit 2 consisting of a DC reactor 7 and resistors 9A and 9B separately connected to the DC reactor 7, is controlled.
The circuit is configured to control two shunt circuits.
Therefore, when the rotational speed increases and reaches the first predetermined value, the contactor 8A is first turned on and one of the shunt circuits consisting of the reactor 7, contactor 8A and resistor 9A is closed, and the rotational speed further increases. When the rise reaches the second predetermined value, the contactor 8B is also turned on, and the reactor 7, contactor 8B and resistor 9
The other shunt circuit consisting of B is also closed. Therefore, as shown by the broken line in Fig. 4, the magnitude of the interpolation shunt current I _B changes stepwise as the rotation speed increases, making it possible to always operate the DC machine 1 with non-spark rectification. can.

However, in this method, in addition to the DC machine 1, the rotation speed detector 5, the contact controller 6, the DC reactor 7, the contactors 8A, 8B, and the resistors 9A, 9
A rectification compensator consisting of B is required, and this rectification compensator is placed separately at an appropriate position away from the DC machine 1 depending on the installation site of the DC machine 1, so the rectification compensator is connected to the DC machine 1. Wiring work must be done on-site, which increases the time required for on-site installation work and increases the installation area. In addition, in a DC machine that frequently performs reversible operation, the contactor opens and closes frequently, so the life span of the contactor contacts is a problem, and maintenance thereof is troublesome.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a DC machine that can prevent the non-spark zone shifting development simply by modifying the internal structure of the DC machine body, without requiring a rectification compensation device separate from the DC machine. It's about doing.

[Summary of the invention]

In order to achieve this object, the present invention provides a commutator magnetic flux adjustment that extends substantially circumferentially between the main pole iron core and the commutator iron core at a position that is biased toward the armature side than the field winding and the commutator winding. A magnetic member is provided, and during low-speed operation with a strong field, a small amount of leakage copole magnetic flux flows through this magnetic member, and during high-speed operation with a weak field, a large amount of leakage copole magnetic flux flows through this magnetic member to adjust the copole. It is characterized in that the amount of interpole magnetic flux flowing from the to the armature is automatically changed according to the rotation speed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG.

FIG. 1 is an exploded view of essential parts of a bidirectional rotating DC machine according to an embodiment of the present invention. In Figure 1,
10 is a ring-shaped yoke with a main pole 1 on the inner circumference side.
1 and a commutative pole 12 are provided. The main pole 11 includes a main pole iron core 13 having a magnetic pole piece portion 13A and a field pole winding 14.
It serves to provide main magnetic flux to the armature winding 15 of the armature 2 rotating inside the stator. Also,
The commutator 12 consists of a commutator core 16 and a commutator winding 17, and serves to provide reinforcing magnetic flux to generate a rectified electromotive force during a rectification phenomenon in which the current flowing in the armature winding 15 is reversed.

Such a structure is the same as the conventional one, but in this embodiment, a magnetic field is further provided between the side surface of the magnetic pole single side 13A of the main pole core 13 and the side surface of the commutating pole core 16 near the armature 2 side. The commutating magnetic flux adjusting magnetic members 18A and 18B made of a magnetic material and connected to each other are fixed by welding or the like using a mounting metal (not shown).

The operation of the DC machine configured as described above during low speed operation and high speed operation will be explained in detail with reference to FIGS. 2A and 2B.

First, during low-speed operation as shown in Fig. 2A, the field is strong, so the main pole flux φ _MP1 generated by the field winding 14 is large, and the magnetic flux density of the main pole iron core 13 and the yoke 10 is high. , magnetically saturated. Also, part of the interpolation flux φ _IP1 to _{φ IP3} generated by the commutator winding 17 and passing through the commutator iron core 16 is generated by the interpolation flux adjusting magnetism provided between the different poles of the main pole 11 and the commutator 12. It leaks from the magnetic pole piece portion 13A to the main pole iron core 13 via the member 18B. Here, since the main pole iron core 13 and the yoke 10 are magnetically saturated as described above, the amount of leakage magnetic flux is small, only φ _IP1 , and the remaining interpole magnetic flux φ _IP2 ,
φ _IP3 enters the armature 2 side and acts as a commutating magnetic flux to generate a rectified electromotive force.

Next, during high-speed operation as shown in Fig. 2B, the main magnetic flux φ _MP2 due to the field winding 14 is weakened.
is small, and the magnetic flux density of the main pole iron core 13 and the yoke 10 is low, resulting in a magnetically unsaturated state. Therefore, the commutating magnetic flux easily leaks to the main pole iron core 13 via the commutating flux adjusting magnetic member 18B, and the commutating flux φ _IP1 to φ _IP3
Of these, φ _IP1 and φ _IP2 become the amount of leakage magnetic flux to the main pole iron core 13, and only the remaining φ _IP3 acts as a interpolation magnetic flux that enters the armature 2 side and generates a rectified electromotive force.

Therefore, the leakage magnetic flux amount φ _IP1 during low-speed operation and the leakage magnetic flux amount (φ _IP1 + φ _IP2 ) during high-speed operation are necessarily φ _IP1 < (φ _IP1 + φ _IP2 ), and conversely, the electric The amount of interpole magnetic flux to generate the rectified electromotive force incident on the element 2 side is (φ _IP2 + φ _IP3 ) during low-speed operation and φ _IP3 during high-speed operation, and inevitably (φ _IP2 + φ _IP3 ) > φ _IP3
becomes. In this way, since the amount of commutating magnetic flux during high-speed operation is smaller than the amount of commutating magnetic flux during low-speed operation, the no-spark zone movement phenomenon can be prevented only by the DC machine main body.

In the above embodiment, both ends of the copole flux adjusting magnetic member are fixed in close contact with the side surfaces of the main pole iron core and the commutator core, but at least one end of the copole flux adjusting magnetic member is It may be fixed to the side surfaces of the pole core and commutator core with a gap left therebetween.

At this time, in order to adjust the amount of leakage magnetic flux according to the amount of movement of the non-sparking band of the DC machine, the dimensions of the air gap may be changed or the cross-sectional area of the magnetic flux adjusting magnetic member of the commutator may be changed. You can also change it.

〔Effect of the invention〕

As explained above, according to the present invention, the commutating magnetic flux extends approximately in the circumferential direction between the main pole iron core and the commutating pole iron core at a position that is closer to the armature than the field winding and the commutating pole winding. An adjusting magnetic member is provided, and a small amount of leakage commutating magnetic flux is allowed to flow through this commutating magnetic flux adjusting magnetic member during low-speed operation with a strong field, and a large amount of leaking commuting magnetic flux is allowed to flow through the commutating magnetic flux during high-speed operation with a weakening field for compensation. Since the amount of interpolation magnetic flux flowing from the poles to the armature is automatically changed according to the rotation speed, there is no need for a separate rectification compensation device for the DC machine body as in the past. The no-spark zone movement phenomenon can be prevented by slightly modifying the internal structure. As a result, on-site installation time can be shortened, and the installation area can also be reduced.

[Brief explanation of drawings]

Fig. 1 is an exploded view of the main parts of a DC machine according to an embodiment of the present invention, Fig. 2 A and B are explanatory diagrams of the operation of the DC machine shown in Fig. 1 during low-speed operation and high-speed operation, and Fig. 3 The figure is a block circuit diagram of a conventional rectification compensator, and FIG. 4 is a characteristic diagram showing the phenomenon of no-spark band movement with respect to rotational speed. 2... Armature, 10... Yoke, 11... Main pole,
12...Commuting pole, 13...Main pole iron core, 14...Field winding, 15...Armature winding, 16...Commuting pole iron core,
17...Commuting pole winding, 18A, 18B...Commuting magnetic flux adjusting magnetic member.

Claims (1)

[Claims] 1. A rotor having an armature and a commutator, a yoke,
A plurality of main poles consisting of a main pole iron core and a field winding are attached to the inner circumferential side of the yoke, and a commutating pole iron core and a commutating pole winding are attached between the main poles on the inner circumferential side of the yoke. In a DC machine, which is equipped with a plurality of commutating poles made of wires and a stator having brushes that are in sliding contact with the commutator, and which performs a stronger field during low-speed operation and a weaker field during high-speed rotation, the main pole iron core and It extends substantially circumferentially between the field winding and the commutator core at a position closer to the armature than the field winding and the commutator winding, and prevents leakage commutator magnetic flux during low-speed operation with a strong field. A commutator flux adjustment system that automatically changes the amount of commutator flux flowing from the commutator to the armature in accordance with the rotation speed by circulating a large amount of leakage commutator flux during high-speed operation with a weakened field. A DC machine characterized by being provided with a magnetic member. 2. Claim 1 is characterized in that the magnetic flux adjusting magnetic member of the copole is supported with an air gap relative to at least one of the main pole core and the commutator core. DC machine.