JPH0728515B2 - Current collector for rotating electric machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rotary electric machine that controls a speed by changing a secondary excitation frequency by frequency conversion and transposition, and particularly includes a current collector ring for a neutral point. The present invention relates to a current collector suitable for a variable speed generator.

[Conventional technology]

Conventionally, in a current collector that supplies a secondary side excitation current of a winding type rotary electric machine of a vertical axis by a frequency converter (for example, a device such as a cycloconverter) using a thyristor, each layer is supplied to supply three-phase power. Only the current collector ring (slip ring) corresponding to was attached. That is, for example, as shown in FIG. 2, in the case of a three-phase induction machine, one current collecting ring is prepared for each phase of U, V and W. However, when a variable frequency AC secondary current is supplied using the frequency conversion device 24 using a thyristor, for example, when the current is switched from positive to negative in the U phase, there is a no current period due to the performance of the thyristor. Inevitably, other V-phase or W-phase is distorted, which has recently been found to have a bad influence on the system. As a countermeasure against this, as shown in FIG.
By pulling out the neutral point and preparing a current collector ring also at this neutral point, the remaining V-phase and W-phase thyristors each pass through the neutral point even during the U-phase no-current period. A method for allowing an electric current to flow and for allowing a sinusoidal alternating current to flow has been devised. However, when the neutral point is pulled out and a current collector ring is added, the amount of carbon dust generated increases by that amount, and
There is a drawback that the amount of heat generated on the sliding surface increases and the performance of the current collector as a whole is degraded.

Incidentally, the current collector 21 of the wire wound induction machine as shown in FIG.
It is shown in Chapter 9 etc. of thyristors and power electronics (written by Katsumi Hirayama) published by Technical Review Co. 23 is the primary winding,
25 is a system.

[Problems to be solved by the invention]

The above-mentioned prior art does not take into consideration the current value and voltage value in the steady state of the neutral point phase, and there is a problem about the influence of carbon dust generated from the brush and the heat generated on the sliding surface on other phases. It was

The object of the present invention is to provide the optimum position of the current collector ring of the neutral point phase,
It is to provide a current collector that is less affected by carbon dust and generated heat.

[Means for solving problems]

The above-mentioned purpose is to arrange the current collecting ring for the neutral point below the current collecting ring of any other phase, and to allow the cooling air to flow from top to bottom,
This is achieved by making the outlet of the cooling air closer to the neutral point current collecting ring than any other phase current collecting ring.

[Action]

The current value of the neutral point phase during steady operation is The voltage value is about 1/10. Therefore, the amount of current generated is smaller than that of the other phases, so less heat is generated during sliding, and the voltage value is low, so there is a large margin for short circuits. However, when a phase short-circuit trouble occurs in the neutral point phase and other phases, a current of the same magnitude as the other phases flows, so the amount of brazing is the same as that of each of the other phases. It can be said that the amount generated is the same as that of the other phases.

Such a neutral point phase is installed below each of the other phases, cooling air is made to flow from the top to the bottom, and the outlet of the cooling air is arranged at the neutral point current collecting ring more than any other phase current collecting ring. Since it is close to, the influence of carbon dust from each other phase and the generated heat is stronger than any other phase, but as mentioned above, there is a margin in the current value and voltage value in the steady state. It is offset by the margin and the same performance as other phases can be maintained.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. U, V, W, phases from the AC secondary excitation winding and N phases of the neutral point phase are sequentially arranged in the axial direction, and the collector ring 6 for the N phase is the collector ring of U, V, W phases.
It is installed at the bottom of 3, 4 and 5, and the cooling air and carbon dust discharge routes of each collector ring are supplied from above and discharged from fan 11 from below.

According to this embodiment, the carbon dust generated in the U, V, W phases and the combined amount of heat generated are added to the N phase, but the N phase current and voltage tolerance is higher than that of other U, V, W phases. Since it is much higher, a stable current collector can be obtained compared to the structure in which any one of the U, V, and W phases is installed at the bottom. In the figure, 1 is a rotating shaft, 2 is an insulator, and 7 to 10 are braces.

〔The invention's effect〕

According to the present invention, since a current collecting ring having a high tolerance for current and voltage can be arranged in the current collecting ring of a portion where most carbon dust is collected and the amount of heat is large, a current collecting device having stable performance. Is obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a current collector showing an embodiment of the present invention,
2 and 3 are system diagrams of a conventional wound-rotor induction machine. 3,4,5,6 …… Current collector ring, 21 …… Current collector, 22 …… Secondary winding, 23 …… Primary winding, 24 …… Frequency converter.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Yasaka 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hideo Tanaka, Auditor, Hitachi Plant, Hitachi, Ltd. (56) References JP, U)

Claims (1)

[Claims] 1. A vertical axis winding-type rotary electric machine comprising a primary winding and a secondary winding, wherein the secondary winding is AC secondary-excited through frequency conversion transposition using a thyristor. A current collector ring for supplying the secondary winding AC alternating excitation power from the converter is provided with one phase for neutral point, and these current collector rings are formed so as to be cooled by cooling air. The current collecting ring for the neutral point is disposed below the current collecting ring of any other phase, the cooling air is caused to flow downward from above, and the outlet of the cooling air is changed to another. A current collecting device for a rotating electric machine, characterized in that the current collecting ring for a neutral point is located closer to the current collecting ring for the throat than the current collecting ring.