JPS6048985B2 - polyphase alternating current motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyphase alternating current motor with an improved armature winding for problem-free split winding starting.

For polyphase AC motors such as three-phase synchronous motors, various starting methods are selected in consideration of the influence on the connected power source, the influence on the driven load, the starting characteristics of the motor itself, etc.

These starting methods include reactor starting, condolfer starting, starting using a starter motor, and among these, split winding starting is a simple method that does not require special equipment and has good starting efficiency. Split-winding starting is a method in which the armature winding is divided into several parallel circuits, a part of which is used during starting, and the parallel circuits are activated as appropriate depending on acceleration. Many specific methods are known, but among them, two or more parallel circuits are provided in the armature winding of an AC motor with a relatively large number of poles, and the wires belonging to one circuit are There is a method of preventing magnetic imbalance during starting by dividing the rings into two groups based on their geometrical arrangement and arranging each group at diametrically opposite positions on the armature core. A more specific example will be described below with reference to the drawings. The AC motor has 8 poles, and the armature winding connections are 2xY. Figure 1 is a schematic diagram of the connection, including the connection. Connect the output terminal of the phase winding to U.
, ,V, ,W, ,U those belonging to the #2 circuit. ,V.
,W. shall be. Connect #1 Shiya-ketsu to the power supply side of all windings, and connect #2 Shiya-ketsu to the power supply side of only #2 circuit. As for the starting order, first leave #2 Shiya-ketsu open, then put in #1 Shiya-ketsu. Then, power is supplied only to the armature winding of the #1 circuit, and the AC motor starts with a starting current of about 112 and a starting torque of about 112 when all windings are used. When the engine accelerates to an appropriate speed, power is supplied to all windings and the AC motor is fully accelerated with the starting current and torque of one engine, reaching full speed and entering constant speed operation. FIG. 2 shows the geometrical arrangement of the armature coils when the AC motor shown in FIG. 1 is viewed in the axial direction. For simplicity, Figure 2 shows only the #1 circuit U phase from the output terminal to the neutral point "'0".
'' shows connections up to. The inner gear-shaped figure indicates the rotor magnetic pole, and is drawn to clearly indicate the relative position with the armature winding. As is clear from the figure, there are two wire groups belonging to the #1 circuit, in terms of the U phase, the wire groups 1-U and l-(-U) in the first quadrant connected from the output terminal U1 and their 1 to the neutral point ゜“0゛” connected via a crossover wire.
-U, l- (-U) wire rings are arranged and connected at geometrically opposite positions on the armature core, so an unbalanced magnetic attraction force that attracts the rotor to only one side is not generated. . Therefore, even if the #1 circuit breaker is turned on and power is supplied to only the coils of the #1 circuit for acceleration, no abnormality will occur due to magnetic imbalance.
When the rotor has almost completed its acceleration, turn on the #2 breaker.
Even if power is supplied to the coils belonging to the #2 circuit, no unbalance will occur since the coil groups belonging to the #2 circuit are arranged and connected in geometrically symmetrical positions. In this conventional method, when the number of parallel circuits of the armature winding is m, if the number of poles of the AC motor is not an additive multiple, the two wire ring groups belonging to one circuit have the same number of poles. Therefore, the two groups cannot be arranged symmetrically, resulting in an unbalanced magnetic attraction force, resulting in problems such as excessive oscillating current and torque pulsation during startup. This will be specifically explained with reference to FIG. The armature winding arrangement shown in the figure is for a 2XY connection, w-pole AC motor. That is, the number of parallel circuits m is 2゛, so ? The multiples of are 4, 8, 12, 16,・
・And one width is not a multiple of addition. The overall connection including the shield and disconnector is the same as in Figure 1, and the drawing instructions for winding arrangement and connection are as in Figure 2.
Similar to the figure, however, the positions of the rotor magnetic poles are omitted. In Fig. 3, there are two wire ring groups belonging to the #1 circuit, in terms of the U phase. 1-U, l-(-
1 (1U), 1-U, l- of the third quadrant leading to the neutral point ゛0゛ connected to the line ring group of U) and the wire through the connecting wire.
It cannot be arranged symmetrically with the line ring group (-U). In other words, the wires belong to the #1 circuit. The group consists of five poles, and when divided into two groups, it is not possible to have the same number of poles. In FIG. 3, the wire ring group near the outlet terminal U constitutes two poles, and the wire ring group near the neutral point constitutes three poles. Furthermore, in Figure 3 “
The line/ring group on the symmetrical side of the line/ring group at the position marked with ×゛ is marked with “∆”, but it does not belong to #1 circuit but belongs to #2 circuit, so it is connected to #1 circuit. When starting and accelerating the power supply to a group of wire wheels, magnetic imbalance occurs and the above-mentioned problems occur, making it impossible to apply the split winding starting method.Therefore, the present invention can solve the problem of magnetic imbalance even in AC motors with a pole number that is not a multiple of the sum. An object of the present invention is to obtain an AC motor in which split winding starting can be freely adopted even in the case of an arbitrary number of poles without causing equilibrium.

An embodiment of the AC motor according to the present invention will be described in detail below with reference to the drawings.

FIG. 4 is a diagram showing the arrangement and connection of the armature windings of a 2XY-connected m-pole AC motor, similar to FIG. 3, but to which the present invention is applied. In other words, the coil groups of each phase belonging to the poles located at the opposite positions of Δ and Connect them so that they belong to the respective circuits. Ru. That is, the small group of coils is exchanged between the #1 circuit and the #2 circuit. When connected in this way and the #1 circuit breaker shown in Figure 1 is turned on to supply power to the armature winding of the #1 circuit, the conventional winding connection shown in Figure 3 causes magnetic unbalance. Only half of the small group of wire rings at the poles at the positions indicated by the × marks are excited, and on the other side, the wire ring groups at the poles at the positions indicated by the Δ marks, which were not previously excited, are now being energized. Since only half of the small groups are excited, the poles marked with x and the poles marked with Δ in FIG. 4 are in an almost magnetically balanced excitation state, and the magnetic unbalance almost disappears. The reason why it does not disappear completely will be explained later. Next, when the #2 circuit breaker is turned on and power is also supplied to the armature winding of the #2 circuit, all the windings of this AC motor are energized, the magnetic unbalance disappears, and it accelerates to full speed. It operates with the same characteristics as a 2XY connection AC motor. Next, we will explain in detail the method of dividing the line ring groups belonging to the poles marked Δ and Explain why.

In Figure 4, when the terminals of each phase of Ul, U2: ■1, ■2: Wl, W2 are connected to the R, S, and T phases on the power supply side, a clockwise (clockwise rotation) rotating magnetic field is generated. The wire rings are arranged and connected so as to occur. Now, looking at the wire ring small groups marked with Δ and × in the #1 circuit of the U phase, on the side marked with Δ, the wire rings spatially occupy a position on the lagging side within one phase zone with respect to the rotation direction of the magnetic field. On the other hand, on the opposite side marked with an x, the line ring within one phase zone spatially occupies a position on the advancing side. Similarly, if we look at the U-phase #2 circuit, it has a wire arrangement in which, contrary to the #1 circuit, it advances on the Δ side and lags on the × side. Therefore, since both the #1 circuit and the #2 circuit include a small group of wire wheels in a lagging position and a small group of wire wheels in an advanced position, the phases of the induced voltages in both circuits match, and a circulating current flows between both circuits. do not have. However, in this position, as is clear from FIG. 4, the two wire ring groups in one circuit are located on almost opposite sides of the armature, but not in exactly opposite positions. Therefore, a slight magnetic imbalance will remain, but this is unavoidable in order to prevent circulating current from flowing between the two circuits as described above. However, in FIG. 4, the order of allocating the W-phase wire ring small group to the #1 circuit and #2 circuit is reversed from that for the other U and ■ phases. In this way, magnetic unbalance is further reduced than when all three phases are divided in the same order. Furthermore, when forming a small group of coils, if the coils are allocated alternately to the #1 circuit and the #2 circuit, the magnetic unbalance can be further reduced. When dividing a single-pole, single-phase wire ring group into small groups, it is desirable that each small group have the same number of wire wheels as possible, but if the number of wire wheels on a single pole and one phase is an odd number, it is not possible to make them the same number. Therefore, the residual magnetic unbalance becomes larger than in the case of an even number. In this case, increase the number of wires in the U and V phase small group of #1 circuit on the side marked with △ in Figure 4, and decrease the number of wires on the small group of -W phase at the same time on the side marked with × on the opposite side. On the side #
The number of wires in the -U, -■ phase wire ring small group of one circuit is small, and W
Increasing the number of wires in a small group of phases has the effect of further reducing magnetic imbalance. According to the present invention described above, by simply and easily changing the division and connection of the coil group for each pole and each phase, split winding starting can be adopted with a circuit that does not change externally at all even in the case of any number of poles. An AC motor is obtained, and there is a great advantage that there is no restriction on the number of poles when adopting the split winding starting method.

[Brief explanation of the drawing]

Figure 1 is a connection diagram of a split winding starting method, Figure 2 is an armature winding arrangement and connection diagram of an 8-pole AC motor viewed from the axial direction, and Figure 3 is a connection diagram of a single-pole AC motor viewed from the axial direction. FIG. 4 is a diagram showing the arrangement and connection of armature windings as seen from the axial direction of a one-lucid AC motor according to the present invention. 1... Coil group belonging to #1 line, 2...
...Coil group belonging to #2 line.

Claims (1)

[Claims] 1. When performing split winding starting by installing two or more parallel circuits in each phase of the armature winding, two poles facing each other with respect to the axis occur when the number of poles is not divisible by twice the number of parallel circuits. Below, the wire groups of each pole and each phase belonging to different parallel circuits are divided, and the divided wire rings or wire ring subgroups are connected under both poles as if they belong to each parallel circuit, and the same parallel circuit is connected. A polyphase AC motor equipped with an armature winding in which wire rings or small groups of wire rings belonging to the above are arranged at opposite pole positions.