JPS61177145A - Single-phase ac motor - Google Patents

Abstract

PURPOSE:To readily control the rotating direction and speed of an AC motor by providing the same number of shading coils as a plurality pairs of stator coils in addition to the stator coils, and selectively opening or closing variable impedance elements connected with the shading coils. CONSTITUTION:Poles 3-6 are formed on a stator core 1, and stator coils 9-12 driven by a single-phase AC power source 17 are respectively wound on the poles 3-6. The coils 9, 10 and 11, 12 are respectively wound in the same polarity as but different polarity from the coils 9, 10 and 11, 12. Shading coils 13-15 are respectively wound on the poles 3-6, and connected with switches 18-21 and variable impedance elements 22-25. Switches 18, 20 and 19, 21 and impedances 22, 24 and 23, 25 are cooperated. The rotating direction of a motor is reversed by switching the switch group, and the rotating direction is controlled by varying the impedance. Thus, the rotation of the single-phase motor can be simply controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a single-phase AC motor in which starting torque is generated by a shaded coil.

[Technical Background of the Invention] Conventionally, this type of motor has a stator coil wound around each of a plurality of pairs of magnetic pole parts provided in a stator core, and a short-circuit ring made of a conductive material formed in a slit formed in each magnetic pole part. It was designed to fit a shaded coil.

[Problems with Background Art] Incidentally, in order to freely change the speed of a single-phase AC motor, an extremely complicated speed control device is generally required. For example, the voltage control method requires a voltage control circuit using power transistors, etc., and the frequency control method also requires an inverter device using power transistors, thyristors, etc., both of which are extremely expensive. be.

Single-phase AC motors using shaded coils are no exception; in the conventional configuration described above, the phase of the lagging magnetic flux generated by the shaded coil cannot be changed, so the generated torque is fixed, and therefore the speed cannot be changed. The problem is that an expensive speed control device must be used. However, since the shaded coil is fixedly installed,
The disadvantage is that it is not possible to reverse the direction of rotation.

[Object of the Invention] An object of the present invention is to provide a single-phase AC motor that can change the generated torque with a simple configuration, can perform speed control at low cost, and can also reverse the rotation direction. .

[Summary of the Invention] The present invention provides a stator core having a plurality of pairs of magnetic pole portions, and a stator core having a plurality of pairs of magnetic pole portions, and adjacent pairs of magnetic pole portions wound around each magnetic pole portion having the same polarity, and adjacent pairs of magnetic pole portions having different polarity from each other. The stator coil connected to the power supply and the one wound around each of the magnetic pole parts and wound around one and the other of the paired magnetic pole parts are selectively short-circuited via variable impedance elements, respectively. By having a configuration including a shaded coil, the direction in which the delayed magnetic flux is generated is made variable, and the delayed magnetic flux caused by the shaded coil is changed by changing the impedance of the variable impedance element.

[Embodiments of the invention] One embodiment will be described with reference to the drawings.

First, in FIG. 2, reference numeral 1 denotes a stator core, which consists of an annular portion 2 surrounding a blind-shaped rotor (not shown) and an annular portion 2.
2 in a form that can be integrally extended at an angular interval of 906 on the outer circumference of the
It is provided with pairs, that is, four magnetic pole parts 3 to 6. A rectangular frame-shaped yoke core 7, which connects the proximal ends of the respective machine pole parts 3 to 6, is integrated into the outer peripheral portion of the stator core 1 by press fitting.

Stator coils 9 to 12 and shaded coils 13 to 16 are wound around each of the machine pole parts 3 to 6 via a bobbin 8, respectively. As shown in FIG. 1, the stator coils 9 to 12 are all connected in series to form a single-phase AC power supply
It is connected to the. Here, adjacent magnetic pole parts 3 forming a pair
．． 4 have the same polarity, and the pair of magnetic pole parts 5.6 adjacent to this pair of magnetic pole parts 3.4 also have the same polarity and different polarity from the pair of magnetic pole parts 3.4. It is connected. On the other hand, variable resistors 22 to 25, which are variable impedance elements, are connected to each of the shaded coils 13 to 16 via switches 18 to 21, respectively.
6 can be short-circuited. Among these switches 18 to 21 and variable resistors 22 to 25, a shaded coil 13. The switch 18.20 and the variable resistor 22.24 connected to each other magnetic pole portion 4.15 are both configured to interlock with each other.
The switch 19.21 and the variable resistor 23.25, which are connected to the shaded coil 14.16 wound around the coil 14.6, are also both configured to interlock with each other.

Next, the operation of the above configuration will be explained. For example, when a single-phase alternating current is passed from the power supply 17 to each stator coil 9 to 12 with the switch 19.21 closed and the switch 18.20 opened, the magnetic pole portion 3.4 of the stator core 1 and the magnetic pole portion 5.6 of the stator core 1 are connected to each other. are excited so that they have different polarities. As a result, a part of the main magnetic flux from each of the stator coils 9 to 12 interlinks with each of the shaded coils 13 to 16, and an electromotive force is generated. Here, since the switch 19.21 is closed, the variable resistor 23.25 is connected to the shaded coil 14.16.
A current that lags behind the electromotive force flows through the coil, producing a magnetomotive force, but since the switch 18.20 is open, no current flows through the shaded coil 13.15, and no magnetomotive force is produced. On the other hand, the current flowing through the shaded coils 14.16 and the phase of the resulting magnetomotive force are different from the electromotive force in the shaded coils 14.16.
16 and the variable resistors 23 and 25. Therefore, in each magnetic pole section 4.6, the combined magnetomotive force of the magnetomotive force of the stator coil 10.12 and the magnetomotive force of the shaded coil 14.16
．． A predetermined lagging magnetic flux that is the most delayed with respect to the main magnetic flux of No. 5 is generated.

As a result, a so-called moving magnetic field is generated, so that the blind rotor starts in the direction of the arrow in FIG. In this state, if the resistance value of the variable resistor 23.25 is changed, the current flowing through the shaded coil 14.16 will change, causing the shaded coil 14.1 to change.
Since the magnetomotive force of 6 also changes, the amount of delayed magnetic flux at the magnetic pole portion 3.5 changes and the generated torque changes. Therefore, the rotational speed of the blind rotor changes under the condition that the load torque is constant. The changes in this generated torque are shown in Figure 3.
It is shown as a plurality of torque curves in the first quadrant of the speed characteristic diagram. In addition, in the figure, the variable resistor 23,
Although the case where the resistance value of No. 25 is changed stepwise has been shown, it goes without saying that if the resistance value is changed continuously, the rotational speed will also be changed continuously. On the other hand, switch 18.2
When single-phase alternating current is passed through each stator coil 9 to 12 with 0 closed and switches 19 and 21 open,
Contrary to the above case, the magnetic pole parts 3 and 5 in the magnetic pole part 4.6
Since a lagging magnetic flux is generated with respect to the main magnetic flux, the blind rotor rotates in the direction opposite to the arrow. Even in this case, by changing the variable resistors 22, 24, the generated torque changes as in the above case, so the rotation speed can be changed continuously. The torque curve in this case is shown in the third quadrant of the torque-speed characteristic diagram in FIG.

As described above, according to this embodiment, although it is a single-phase AC motor whose speed is originally difficult to control, the generated torque is changed by changing the resistance value of the variable resistor 23.25 or 22.24. Rotation speed can be changed freely. Moreover, the configuration for that purpose is the shaded coils 13 to 16.
Since it has an extremely simple configuration in which the variable resistors 22 to 25 are connected in a short-circuit manner, it can be manufactured at a significantly lower cost than conventional speed control devices. In addition, in a conventional single-phase AC motor with a configuration in which a speed control tap is provided on the stator coil, the speed can be adjusted to only 2.3 types at most, but in this embodiment, stepless speed control can be performed. This makes the range of applications extremely wide. Furthermore,
Shading coils 13 to 16 are wound around all the magnetic pole parts 3 to 6, and switches 18 to 21 are wound around each of the shaded coils 13 to 16.
Since the variable resistors 22 to 25 are connected through the
．． 20 can be rotated in different directions depending on when it is closed, and the range of applications can be further expanded.

In the above embodiment, the variable resistors 22 to 25 are used as the variable impedance elements, but the present invention is not limited to this. For example, a transistor may be used as the variable impedance element, and the switch 18
Thyristors may be used in place of 21 to 21. In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications within the scope of the invention, such as providing three or more pairs of magnetic pole parts, for example.

[Effects of the Invention] As described above, the present invention has a configuration in which one and the other of a pair of shaded coils wound around a plurality of pairs of magnetic pole parts are selectively short-circuited via a variable impedance element. This has excellent effects in that speed control can be carried out at extremely low cost and the direction of rotation can also be reversed.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a connection diagram of a stator coil and a shaded coil, FIG. 2 is a longitudinal sectional front view of a stator, and FIG. 3 is a torque-speed characteristic diagram. In the drawing, 1 is a stator core, 3 to 6 are magnetic pole parts, 9 to 12 are stator coils, 13 to 16 are shaded coils, 1
7 is a power supply, 18 to 21 are switches, and 22 to 25 are variable resistors (variable impedance elements).

Claims (1)

[Claims] 1. A stator core having a plurality of pairs of magnetic pole parts, and a stator core connected to a power source so that adjacent pairs of magnetic pole parts wound around each of the magnetic pole parts have the same polarity, and adjacent pairs of magnetic pole parts have different polarities. a stator coil wound around each of the magnetic pole parts, and a shaded coil wound around one and the other magnetic pole parts of each pair of magnetic pole parts, which are selectively short-circuited via a variable impedance element. A single-phase AC motor consisting of