JPH0132744B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates particularly to the rotor of a repulsion-start single-phase induction motor, and more particularly to improving the starting characteristics.

[Prior Art] A repulsion start type single-phase induction motor has a large starting torque, but has the disadvantage that the torque is not very large when the repulsion characteristic changes to the squirrel cage characteristic. This drawback can be improved to some extent by increasing the resistance of the secondary winding, but if the resistance of the secondary winding is increased, the stall torque will shift to a point where the slip is large.
It may be inappropriate depending on the type of load.
In addition, it was developed as a repulsion start type single-phase induction motor in 1963.
The one described in Publication No. 11662 is publicly known. This is an attempt to increase the starting torque of a repulsive start type single-phase induction motor by using multiple windings in the rotor winding.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to increase the torque when transitioning from repulsion characteristics to cage-shaped characteristics compared to conventional ones. To provide a repulsion start type single-phase induction motor which can prevent stall torque from shifting to the side with larger slip.

Another object of the present invention is to construct a repulsive start type single-phase induction motor that can reduce the current when the short circuit is activated compared to conventional motors.

[Summary of the Invention] That is, in the present invention, in a commutator provided with a shunt that contacts each segment and shorts the secondary winding, a first shunt that operates at a first rotational speed; and a second shunt operating at a second rotational speed. The second rotation speed is selected to be greater than the first rotation speed.

The rotor winding may be wave-wound or lap-wound.

[Operation] Now, in the structure constructed as above, all the short circuits are initially separated from the segments. Then it starts showing repulsion characteristics. When a first rotational speed is reached, a first shunt contacts some of the segments.
In this case, a part of the secondary windings connected in series is short-circuited at the segment position, so that the resistance value of the secondary windings becomes smaller. However, since the resistance value at this time is naturally larger than that in the case where all the short circuits contact all segments, a high slip characteristic can be obtained and a larger torque can be obtained than in the conventional one. Also, the current can be kept smaller than in the past.

Now, when the rotational speed is further accelerated from this state and the second rotational speed is reached, the second short circuit also operates, and all segments are short-circuited by the first short circuit and the second short circuit. In this case, the secondary winding acts as a perfect squirrel-cage winding, so the resistance value becomes smaller and the stall torque shifts to the side with smaller slip.

Therefore, the present invention can achieve its intended purpose.

[Embodiment of the Invention] FIG. 1 is a developed view of a rotor winding showing an embodiment of the electric motor of the present invention.

This example will be explained below.

S ₁ ~ _{S 28} are slots provided in the rotor core, 1 ~
56 is a commutator segment. Laply wound coils are applied across slots S ₁ to S ₂₈ using six wire loops.
In other words, 6-S ₁ -S ₇ -7-S ₁ -S ₇ -8-S ₂ -S ₈ -9
-S ₂ -S ₈ -10...2-S ₂₇ -S ₅ -3-S ₂₇ -S ₅ -
Connect in the order of 4-S ₂₈ -S ₆ -5-S ₂₈ -S ₆ -6.

The first short-circuit element is represented by C with an even number, and the second short-circuit element is represented by C with an odd number.

As shown in FIG. 2, these first and second shunts are arranged alternately around a boss 61 that is fitted and fixed to a rotating shaft 60. _The first short circuit elements _{C 2 ,} C ₄ , C ₆ . At the first rotational speed, the first short circuit overcomes the force of the first spring 62.
C ₂ , C ₄ , C ₆ . . . contact segments 1 to 56. The second short circuits C ₁ , C ₃ , C ₅ ... do not contact the segment 1-56 at the first rotation speed, but
At a second rotational speed greater than the first rotational speed, the second
Overcoming the force of spring 63, segments 1 to 56
make contact with.

In the configuration as described above, at the beginning of startup, the first short circuits C ₂ , C ₄ , C _{6 .} . . , C ₅₆ , the second short circuit C ₁ ,
Since _C3 , _{C5, .} This state is shown as a and a' in FIGS. 3 and 4. In both FIGS. 3 and 4, the horizontal axis represents the slip S, and the vertical axis represents the torque T in FIG. 3 and the primary current I in FIG.

When the rotation speed of the electric motor increases and reaches the first rotation speed, the first short circuits C ₂ , C ₄ , C ₆ . . . C ₅₆ contact the segments 2, 4, 6, . state. In other words, two coils inserted into the same slot are connected in series, with both ends connected.

When the rotation speed of the electric motor further increases and reaches the second rotation speed, the second short circuits C ₁ , C ₃ , C _{5 .} . . C ₅₅ also come into contact with the segments 1, 3, 5 . Then, the wires entering each slot are short-circuited one by one. This shows the same characteristics as when the segments of a conventional repulsive start type single-phase induction motor are short-circuited, that is, the characteristics shown as C and C' in FIG. 3 and FIG. 4.

By _the way, the state shown in FIG. 1 _in which only the first short circuits C _{2 ,} C ₄ , _{C 6 . 56} and the second short circuits C ₁ , C ₃ , C _{5 .} . . C ₅₅ are in contact with all segments 1 to 56, it is clear from the above description that the resistance value of the secondary winding is larger than that in the case where all the segments 1 to 56 are in contact with each other. Therefore, in the state shown in Figure 1, b,
The characteristic indicated by b′ is obtained. Therefore the first rotational speed
By selecting V ₁ and the second rotational speed V ₂ as shown in Fig. 3 and Fig. 4, the characteristic curve suddenly shifts to c and c' at the first rotational speed V _1. , the minimum value of torque can be increased,
The maximum current can be kept small, and the slip, which indicates stall torque, can be kept at the same value as the conventional one.

[Effects of the Invention] According to the present invention, as is clear from the above description, in a repulsive start type single-phase induction motor, a short circuit that shorts out a commutator of the motor is operated at a first rotation speed; The second rotation speed is greater than the first rotation speed.
The system is divided into two types: one that operates at a rotational speed of . The resistance of the rotor winding when only the first short circuit contacts the segment is smaller than when both the first and second short circuit are apart from the segment; It is configured so that it is larger than when it is in contact with the

Therefore, the torque when changing from the repulsion characteristic to the cage characteristic can be increased compared to the conventional one, and the current when the short circuit is activated can be made smaller than the conventional one.

[Brief explanation of drawings]

Fig. 1 is a developed view of the secondary side showing an embodiment of the repulsion start type single-phase induction motor of the present invention, Fig. 2 is a sectional view showing an example of the short circuit device used in the present invention, Fig. 3 and Fig. FIG. 3 is a characteristic curve diagram of the invention electric motor. 1 to 56 are commutators, C ₂ , C ₄ , C ₆ . . . are first short circuits, and C ₁ , C ₃ , C _{5 .} . . are second short circuits.

Claims (1)

[Claims] 1. The rotor has a rotor core, a rotor winding, a commutator, and a short circuit, and the rotor core has a large number of slots, and the rotor winding is installed in the slot. The commutator has a plurality of segments, each segment being electrically connected to the wire wheel, and the shunt contacting the segment and connecting the rotor to the rotor. In a repulsive start type single-phase induction motor that short-circuits the windings, the shunt is a first shunt that contacts some of the segments when the rotational speed of the rotor reaches a first rotational speed. , a second shunt that contacts the remainder of the segments when a second rotational speed greater than the first rotational speed is reached, and only the first shunt contacts the The resistance of the rotor winding when in contact with the segments is equal to
The repulsion is configured to be smaller than when the shunt is away from the segment, and larger than when the first shunt and the second shunt are in contact with the segment. Starting type single phase induction motor.