JPH03135348A - Multi-stator induction motor - Google Patents

Abstract

PURPOSE:To contrive the improvement of characteristics, reduction of installation cost and simplification of the title motor by a method wherein an induction motor, formed of a plurality of rotors and stators, is formed integrally with an interconnection switching device, switching interconnection of a plurality of stator windings. CONSTITUTION:When switches S1, S2 are opened and a power source opening and closing device S0 is closed at first, a stator winding 11 is connected to another stator winding 10 through series -connection having electrical phase difference of 60 deg.. When an interconnection opening and closing switch S1 is closed subsequently, the terminal X1 of the stator winding 11 and the terminal Z2 of the stator winding 10 are short-circuited whereby the series -connection becomes inbalance. When the interconnection opening and closing switch S2 is closed next, the phase difference becomes 0 deg. in an electric angle. When an interconnection switching device, consisting of the interconnection opening and closing switches S1, S2, is provided in such a manner, a complicated wiring for Y- starting may be eliminated and operation with high torque from a low speed to a high speed may be effected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has a single rotor and a plurality of stators, and has a rotating magnetic field generated around the rotor facing the plurality of stators. This invention relates to a multi-stator induction motor that can generate smooth or soft startup and high torque from low to high speeds by switching the phase difference between the two.

[Conventional technology]

In conventional technology, the number of wires used to connect the power supply and motor is simply considered to be three in three-phase use.
These are limited to small size and low output power. Since a large-sized motor uses a Y-Δ starting device in consideration of the starting current at startup, the number of wires, that is, the number of wires from the Y-Δ starting device to the motor, requires at least six wires.

This Y-Δ starting device is usually centrally installed and placed on a switchboard or the like in order to automate equipment. Therefore, as described above, the number of wires is large.

This also applies to multi-stator induction motors prior to the present invention, and in addition to the Y-Δ starting device described above, each winding is provided with a connection changeover switch for switching the connection of the stator windings to provide a phase difference. It may require as many wires as edges.

[Problem to be solved by the invention]

As the number of wires leading to the motor increases, the costs associated with the wiring equipment also increase. Specifically, the number of wiring cables increases, the diameter of the piping increases due to the increase in the number of cables, the size of the fixture increases, and the cost of wiring equipment increases. Various problems arise, such as improving strength. Moreover, these are treated as a matter of course at the current technological level. However, equipment costs surrounding such electric motors account for a large proportion.

For this reason, the technical object of the present invention is to improve the characteristics of the electric motor and to reduce and simplify the equipment costs, especially the equipment costs surrounding the electric motor.

[Means to solve the problem]

The present invention provides a rotor in which a plurality of conductors attached to a plurality of rotor cores provided at arbitrary intervals on the same rotating shaft are connected in a continuous manner, and the rotor cores are respectively opposed to each other. Means for solving the above problem is achieved by integrally forming an induction motor formed by a plurality of stators disposed around the stator and a connection switching device for switching the connections of the plurality of stator windings. did.

[Function] The multi-stator induction motor of the present invention has a connection switching device integrated with the induction motor that switches the connections of the windings wound around a plurality of stators to create a phase difference between the respective rotating magnetic fields. By doing this, the number of wires to the induction motor can be three in the case of a three-phase specification. Furthermore, the multi-stator induction motor creates a phase difference between the rotating magnetic fields at the time of startup as described above, generates high torque, and can suppress the starting current to a small level, so the cross-sectional area of the conductor can also be made smaller compared to the conventional technology. can.

Therefore, when installing a motor on-site, even if the motor becomes large, it is only necessary to check the three wires and the direction of rotation, which are the same as those for a small motor, reducing wiring material costs and simplifying work.

The connection switching device referred to here refers to a simple open/close switch, a switch using a semiconductor element such as a thyristor/triac, etc., and a timer sequence circuit that controls these switches or a control circuit using a speed detection element centered on the CPU. May include.

〔Example〕

Although the present invention will mainly be described in detail as a two-stator induction motor having a squirrel-cage rotor, it goes without saying that the present invention is not limited thereto. There are also cases of multi-stator induction motors having a wound rotor, and cases where the stator windings are switched between star connection and delta connection to further diversify the torque characteristics. The configuration between the rotor cores is also spaced,
Non-magnetic materials, magnetic materials, etc. may be used.

The present applicant has already given a detailed explanation of the structure and operation of an induction motor comprising a plurality of stators, which is a part of the structure of the present invention, in Japanese Patent Application No. 128314/1982.

An embodiment of an electric motor forming a part of the structure of the present invention will be explained with reference to FIG. Reference numeral 1 denotes a multiple stator induction motor according to the present invention, and the induction motor has the following configuration. Rotor cores 2.3 made of magnetic material are mounted on the rotor shaft 4 at arbitrary intervals. A non-magnetic core 5 is interposed between the rotor cores 2 and 3, or a space is provided between the rotor cores 2 and 3.

A plurality of conductors 6 installed in the rotor cores 2 and 3 are connected to each other in communication with the rotor cores 2 and 3 to form an integral rotor 7, and a plurality of conductors 6 are connected in series. Conductor 6・
Both ends of . . . are short-circuited by short-circuit rings 8, 8. Also,
In this embodiment, the conductor 6 installed on the rotor 7...
The non-magnetic core 5 portions between the rotor cores 2 and 3 are connected via a resistive material 9 that conducts current when a current of an arbitrary vector difference flows.

A first stator 12 and a second stator 13, each having a winding 10.11 on the outer side facing the rotor cores 2 and 3, are arranged side by side in a machine frame 14, and the first stator 12 and the second stator 13 is fixed to the machine frame 14.

In addition, the windings 10.1 of the first stator 12 and the second stator 13
As an example, the connection form No. 1 is a series Δ connection with an electrical phase difference of 60°.

Next, embodiments of the present invention are shown in FIG. 2 and subsequent figures.

What is shown in FIG. 2 is an example of a wiring diagram of a stator winding serving as a wiring switching device. One terminal (U+, V+, W+) of each coil of the stator winding 11 is connected to a power switchgear S.

and connect the other terminals (X+, Y+, Z+) to one terminal (Y2.Z2°X2) of the stator winding 10, and the stator winding 1
The other terminal (V21w2.Y2) of 0 is connected to the terminal (U
+, V+.

W+) in a series Δ connection.

One end of the connection switch S is connected to the other terminal X1 of the stator winding 11, and the other end is connected to one terminal Z2 of the stator winding 10.

The connection switch S2 is connected to the other terminal Y of the stator winding 11 and to one terminal X2 of the stator winding Il+.

The operation of the above configuration will be explained. First, switch S
,,S2 is opened and becomes the power switchgear S. When closed, the stator winding 1 and the stator winding 10 are connected in series Δ with an electrical phase difference of 60°. This is shown in FIG. In other words, the shared voltage E of the coils U1 to X of the stator winding 11 and the corresponding shared voltage E of the coils U2 to X2 of the winding 10.
, - are connected to have an electrical phase difference of 60°.

Then, when the connection on/off switch S (hereinafter referred to as switch S) is closed, the terminals X of stator winding 11 and stator winding 1 are closed.
0 terminal Z2 is short-circuited and the series Δ connection becomes unbalanced. This is shown in FIG.

When unbalanced, part of the winding (V2~Y2V).

~y+) are connected in parallel, and the shared voltage of the coils other than the line CA increases. When the shared voltage increases, the generated torque also increases. This obtained torque characteristic is based on the series △
This shows a torque characteristic intermediate between wire connection and parallel Y wire connection.

Furthermore, in order to make the connection diagram of FIG. 4-1 easier to understand, FIG. 4-2 has been rewritten with a focus on short circuits between lines, that is, switch S1.

Next, when the connection open/close switch S2 (hereinafter referred to as switch S2) is closed, the phase difference becomes the electrical angle O0 as described above. Further, the wiring connections at this time are shown in FIG.

As described above, the two connection switching switches S1 and S2 and the connection of the stator winding provide a connection switching device with three levels of torque characteristics. In other words, the torque characteristics are shown in FIG. 6 for starting, medium speed, and operation.

Here, as shown in FIG. 2, the connection switch S3. When a wiring switching device consisting of S2 is installed on the motor side, only three wires are needed from the power supply side to the motor, and there is no need for complicated wiring for Y-△ starting, which is seen in general large motors. It is possible to create an electric motor that has a small starting current and can be operated at high torque from low to high speeds.

Next, an embodiment in which a control device is incorporated into a wire connection switching device will be described with reference to FIGS. 7 and 8. First, in the configuration shown in FIG. 7, the induction motor 1 is connected to a three-phase power supply 22 equipped with a switching device. Further, the induction motor is integrally provided with a wire connection switching device 20, and a sequence circuit control device 21 consisting of a timer is incorporated in the wire connection switching device.

Next, the configuration shown in FIG. 8 will be explained. The induction motor 1 is connected to a three-phase power supply 22 equipped with a switchgear. Further, the induction motor is integrally provided with a wire connection switching device 20, and the wire connection switching device incorporates a control device 23 composed of a hard logic circuit or the like and a speed detector 24 for detecting the speed of the motor.

Each of the control devices 21 and 23 controls the opening and closing of the above-mentioned connection switch of the connection switching device 20 based on a timer or a signal from the detector 24.

Now, in the above embodiment, the connection switch has a simple switching contact, but it is also an element that can switch from an OFF state to an ON state, or vice versa, which is also used as a trigger element, that is, a thyristor. Or
It includes semiconductor elements such as triacs.

Furthermore, although the three-stage phase difference has been the focus of the embodiments so far, it goes without saying that a method of simultaneously short-circuiting all the lines using an on/off switch can also be realized depending on the load condition.

〔effect〕

As mentioned above, when starting a multi-stator induction motor, the starting current is small and the starting torque is large.In particular, except for equipment that always requires variable speed, it is possible to improve starting performance with constant torque characteristics or square-law reduced torque characteristics. This is a suitable electric motor when the purpose is to reduce time. In addition, for wiring to the motor, the connection switching device is integrated with the motor, so in the case of a three-phase power supply, anyone can wire the motor as long as the motor has three wires and the direction of rotation is correct. .

Furthermore, since this is possible with only three wires, it has become possible to significantly reduce equipment costs by downsizing the equipment surrounding the motor, such as piping materials related to the wiring, and simplifying the associated work.

Therefore, by diversifying the torque, multi-stator induction motors that can generate high torque from low speeds to the rated rotation range will be able to expand their applications and make even greater contributions to all fields that require high-torque motors. Ta.

[Brief explanation of the drawing]

Figure 1 is a side sectional view of a multi-stator induction motor, Figure 2 is a wiring diagram of the wiring switching device, Figure 3 is a wiring diagram for a phase difference of 60°, Figure 4 is a wiring diagram for unbalanced conditions, and Figure 5. 6 is a diagram showing a torque characteristic curve for each connection, FIG. 7 is a control block diagram using a timer sequence, and FIG. 8 is a control block diagram using a logic circuit. DESCRIPTION OF SYMBOLS 1...Multiple stator induction motor, 2.3...Rotor core, 4...Rotor shaft, 5...Nonmagnetic core, 6...
・Rotor conductor, 7... Rotor, 8... Short circuit ring, 9.
...Resistance material, 10.11...Stator winding, 12...
1st stator, 13...2nd stator, 14...machine frame,
20... Phase switching device, 21... Control device, 22.
...Power supply side, 23...Control device, 24...Speed detector.

Claims (1)

[Claims] A plurality of conductors attached to a plurality of rotor cores arranged at arbitrary intervals on the same rotating shaft are arranged around the rotor and each of the rotor cores, respectively, in communication with each other. A multi-stator induction motor, characterized in that an induction motor formed by a plurality of stators and a connection switching device for switching connections of the plurality of stator windings are integrally formed.