JP2739209B2 - Rotor of variable speed induction motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable speed induction motor having good torque characteristics and efficiency and easy speed control.

2. Description of the Related Art One of the methods for controlling the speed of an induction motor is to change the power supply frequency. Although this method allows continuous and wide-range speed control, the frequency converter required by this method is expensive, and harmonics are generally used in the process of converting alternating current into direct current by the frequency converter and converting it back to alternating current. Waves and radio waves are generated, which may cause malfunctions of computers and other various electronic control devices or failures such as overheating of capacitors. Among them, measures are taken against harmonics by installing filters. Yes, but it is costly to install filters. Further, it has a drawback that the performance is generally insufficient at low speed.

Also, the method of controlling the speed by changing the number of poles of the motor is:
Although the speed can be changed stepwise by changing the number of poles, there is a disadvantage that smooth speed control cannot be performed steplessly.

Also, in the method of controlling the speed by changing the voltage of the power supply,
On the other hand, speed control can be performed continuously, but there is a disadvantage that efficiency is deteriorated particularly in a low speed region.

And the method of controlling the speed by changing the slip by changing the secondary resistance in the winding type motor is relatively easy and continuous speed control is possible, but on the other hand, the rotating winding winding from the outside via the brush and the slip ring In order to insert a resistor into the circuit, maintenance is required due to wear of the brush, and the squirrel-cage induction motor has a problem that the speed cannot be controlled by changing the secondary resistance.

To deal with the above problems, for example, Japanese Patent Application Laid-Open
No. 2,290,052 discloses this technique, which comprises two sets of coaxially mounted rotor cores and two independent stator windings opposed to the rotor cores.
Pairs of stators, cage-type conductors that are commonly installed across the rotor cores and are short-circuited at both ends via short-circuit rings, and cage-type conductors between the two rotor cores. A high-resistance element that short-circuits the cage conductors at the center is provided.
It is a twin-core cage type motor that shifts the phase by 0 ° and feeds power in phase during operation after starting.However, the starting torque is increased by shifting the phase between the stator windings by 180 ° at the start to improve the starting characteristics. It is characterized in that it can be operated with normal torque characteristics by matching the phases of the stator windings during operation. Therefore, even if the effect of improving the startability is recognized, this motor cannot be used as a power source of a load requiring a shift because it is not a variable speed motor.

In the above-mentioned Japanese Patent Application Laid-Open No. 54-29005, in the transition from the start-up to the operation, the mutual feed circuits of the stator windings are instantaneously connected in series for the purpose of alleviating a shock due to a sudden change in torque. May be provided in one example, but in this case, the phase shift of the rotating magnetic field is zero.
It is limited to both the points ゜ and 180 ゜ and is not intended for shifting. In addition, the fact that the voltage applied to the stator is reduced to half by switching in series, so that the torque is reduced to 1/4 and the shift control is not possible at all, the gist disclosed in this publication is essential. It is clear from not aiming at shifting.

In short, Japanese Unexamined Patent Publication No. 54-29005 tentatively states "an intermediate step for switching the stator winding between a series connection and a parallel connection with respect to a power supply circuit". It's just a useless connection.

In addition, since there is no special configuration for securing the strength of the rotor, if the gears are shifted and operated for a long time with a phase shift other than 0 ° and 180 °, the rotor will be damaged due to heat and centrifugal force. It had the following.

Japanese Unexamined Patent Publication No. 49-86807 discloses an asynchronous electric motor having a stator having a multi-phase winding and a squirrel-cage rotor. Wherein the stator comprises a first and a second winding section, these sections being coaxially arranged with each other and adjacent different parts of the rotor and supplied with alternating current of the same frequency. And an asynchronous electric motor provided with means for changing the electromotive force induced in the rotor windings by the second winding section. Although the rotation speed can be changed temporarily by providing a phase difference between the stator sections, the torque is small except when the phase angle between the two stator sections is the same, and immediately after the load is applied. Missing operation stops It does not provide any practical use with a failure, and has not solved a serious problem that cannot be operated as a power source that repeatedly starts and stops frequently with a load connected.

[Object of the invention]

The present invention has been made in order to improve the above-mentioned disadvantages of the prior art, and is disclosed in JP-A-54-29005 and JP-A-49-86807.
This publication seeks a unique torque characteristic that cannot be achieved by the summation of the publications described above. The speed control region can be set to any desired speed as a wide range and the speed control can be set in a stepless manner, and can be started with an arbitrary torque. Another object of the present invention is to provide a variable speed induction motor having excellent torque characteristics and efficiency over the entire speed range from the starting point to the maximum rotation speed.

The variable speed induction motor of the present invention is used by connecting to a single-phase or three-phase power supply or the like, and the rotor may be any of a normal cage, a double cage, a deep groove cage, a special cage, and the like. It can also be applied to those of the form

[Means for Solving the Problems] In order to achieve the above technical object, the present invention relates to a method of connecting a plurality of conductors mounted on a plurality of rotor cores to form an integral rotation. A plurality of stators are arranged side by side on a machine frame at an outer peripheral portion facing the plurality of rotor cores formed on the same rotating shaft and provided with an arbitrary interval on the same rotating shaft; Between the plurality of rotor cores not opposed to each other, the plurality of conductors are short-circuited via a resistance material, and the plurality of stators are associated with at least one of the plurality of stators. The phase difference between the voltage induced in the conductor portion of the rotor facing one of the stators and the voltage induced in the corresponding conductor portion of the rotor facing the other stator. An electric motor provided with a voltage phase shifting device for generating A solution is achieved by forming a set of a plurality of adjacent conductors among a plurality of conductors mounted on each of the rotor cores and connecting the rotor cores with each other by one conductor. And

[Action]

According to the present invention, when an arbitrary means causes a phase shift in the magnetic flux of the rotating magnetic field that directly occurs between the stators, the combined voltage induced in the rotor conductor changes according to the phase shift of the magnetic flux, The rotor speed of the rotor can be arbitrarily changed by increasing or decreasing the voltage induced in the rotor conductor.

By the way, since the plurality of conductors mounted on the plurality of rotor cores are short-circuited via the resistance material, a current flows through the resistance material according to the phase shift, and a large torque can be obtained. Efficiency is also improved.

Here, if a current flows through the resistance material, heat is naturally generated, and the strength between the rotor cores is greatly reduced in combination with the action of the centrifugal force. In the configuration of the present invention, a plurality of adjacent conductors among a plurality of conductors provided on each of the plurality of rotor cores are set as a set and connected in a communicating manner by one conductor between the rotor cores. As a result, sufficient strength between the rotor cores can be ensured, so that a sufficiently large current can be applied to the resistance member to obtain a large torque. Also, as described in the examples section,
The manufacture of the rotor has also been simplified.

〔Example〕

Embodiments will be described with reference to the drawings. Reference numeral 1 in FIG. 1 denotes a variable speed induction motor according to the present invention, which has the following configuration.

Rotor cores 2 and 3 made of an iron core are mounted on a rotor shaft 4 at arbitrary intervals, and the rotor core is formed of a plurality of conductors 5 mounted on the rotor cores 2 and 3 respectively. One pair of adjacent conductors 5 is connected, one end thereof is connected by short-circuit rings 6 and 7, and the other side is formed as one set on the other side.
An end 51 was formed. Further, the rotor 8 includes the rotor core 2,
Between the three, the conductor 55 is integrally formed by connecting the conductor 55 to one set of conductors, that is, the end portions 51 of the rotor cores 2 and 3 in a communicating manner. The conductor 55 connected in a communicating manner between the rotor cores 2 and 3 is connected to a resistance material r.
Short-circuited via nickel-chromium alloy, iron-chromium alloy, stainless steel.

The rotor cores 2 and 3 are provided with a plurality of ventilation drums 12 communicating with both side portions 10 and 11 of the rotor 8. Further, a plurality of resistance members r can be formed in the cooling body 13 as, for example, a zigzag shape or any other cooling stirrer. On both sides of the resistance material r, there are provided shielding plates 52 to which a heat insulating material for shielding heat generated by the resistance material r is fixed.

Bearing plates 15 and 16 provided on both sides of a cylindrical machine frame 14 are integrally assembled on both sides by bolts 17, and cooling impellers 19 and 20 are mounted on both sides of the rotor 8. Both ends of the shaft 4 are supported by bearings 21, 21 fitted to bearing plates 15, 16, and the rotor 4 is rotatable.

As shown in FIGS. 1 and 2, a rotating stator 31 having windings 22 and 23 applied concentrically to rotor cores 2 and 3 and a second stator 25 face each other. , A sliding bearing 26 is provided between the machine frame 14 and the rotating stator 31, and the slide bearing 26 is fixed to the machine frame 14 by a stop ring 28. Reference numeral denotes a fixed stator fixed to the inner wall surface of the machine frame 14. A gear is provided on the outer peripheral surface of one side of the rotating stator 31.
A drive unit 33 is fitted and fixed to the outer periphery of the machine frame 14.
29, a driving gear 36 is mounted on a small motor 35 for forward / reverse rotation, and a plurality of air outlets 39 are drilled around the outer periphery of the machine frame 14. The ventilation holes 40 are provided.

A space 66 formed between the rotor cores 2 and 3, the rotating rotor 31 mounted on the slide bearing 26, the second stator core 25, and the machine casing 14 is formed in the wind tunnel 67, In addition, a plurality of openings are opened to communicate with a ventilation drum 67, and the plurality of openings are formed in an arbitrary number of ventilation ports 68 and exhaust ports 69. A motor 72 mounted on a windmill 71 is mounted on a blower cylinder 70 to form a blower 73. The blower 73 is fixed to the machine frame 14, and the blower 74A of the blower 73 is connected to the air outlet 69 and communicates with the ventilation drum 67, and the air outlet 68 for introducing outside air from the other of the air outlets 69 is provided. The air blower 67 communicates with the air blower 67, and the air blower 70 has an exhaust portion 74B formed therein. Further, a cooler, a condenser, a refrigerant gas, and other various refrigerant devices may be connected to the air outlet 69 directly or through a communication pipe.

Driving gear 36 partially inserted into machine frame 14 from opening 37
And a gear 33 fitted to the rotating stator 31 are engaged with each other, and a small motor 35 having a switch forming a driving device 29 and a rotating mechanism 30 including a gear 33 and a driving gear 36 are provided. The rotating stator 31 is connected to the rotating stator 31 so that the rotating stator 31 is rotatable, and the rotatable stator 31 that is rotatable relative to the second stator 25 fixed to the machine frame 14 is transferred to the voltage stator. Formed on phase device 100.

By the rotation of the rotor 8, the outside air is sucked into the machine frame 14 by the cooling impellers 19, 20 from the ventilation holes 40 formed in the bearing plates 15, 16, and the windings 22, The rotor core 2, the conductors 5, etc. are cooled and removed out of the machine frame 14 through the exhaust holes 39, and in the cooling impeller 20, excess air sucked by the impeller 19 is passed through. The fluid flows into the body 12 and the rotor core 2,
3 is cooled, the air sucked from the bearing plate 16 is combined with the air, and cooled by passing through the windings 23 and the second stator 25, and is discharged from the exhaust holes 39B of the machine frame 14 to be cooled. 23, rotor core 2,3,
The function is stably applied to each of the conductors 5. Sign
Reference numeral 38 denotes a solenoid for controlling the movement of the projecting piece.
Is mounted on the machine frame 14 and its protruding piece is engaged with the gear 33 fitted on the rotating retainer 31 so as to be easily attached to the gear 33 when the torque is generated. This is a stopper for preventing rotation.

As shown in FIG. 3, the winding stators 31 and the windings 22 and 23 each having a star connection are connected to the second stator 25 in series. That is, the terminals A, B, and C of the winding 22 of the rotating stator 31 are connected to the commercial three-phase power supplies A, B, and C, and the terminals a, b, and c of the winding 22 are connected.
To the terminals A, B, and C of the winding 23 of the second stator 25,
Terminals a, b and c are short-circuited and connected.

 The operation of the above configuration will be described below.

When current is supplied to the windings 22 and 23 from a commercial three-phase power source, a rotating magnetic field is generated in the rotating stators 31 and 25, and a voltage is induced in the rotor 8, and a current flows through the conductors 5 of the rotor 8 so that the rotor 5 8 rotates. When the rotation amount of each of the second stators 25 with respect to the rotation stator 31 is set to zero, there is no phase shift in the magnetic flux of the rotation magnetic field generated in each of the stators 31 and 25, and the resistance material serving as the connecting material Since no current flows through r ..., it has the same torque characteristics as a general induction motor.

Next, a case will be described in which the small-sized motor 35 is operated to rotate the rotating stator 31, and the rotating stator 31 is rotated by θ at the electric phase angle. The phases of the magnetic fluxes φ ₁ and φ ₂ of the rotating magnetic field generated by the rotating stator 31 and the second stator 25 are shifted by θ, so that the rotating stator 31 and the second stator 25 separate the conductors of the rotor 8. The phases of the voltages 1 and 2 induced in 5... Are shifted by θ. Now, based on the voltage 2 induced on the conductors 5 of the rotor 8 by the second stator 25, the voltage is set to 2 = SE. Here, S is the slip, and E is the induced voltage at the time of slip 1. At this time, the voltage 1 induced in the conductor 5A by the first stator 24 is 1 = SEε ^J0 .

(E = Induced voltage at the time of slip 1) FIG. 5 shows the rotor 8 when the resistance material r ... that short-circuits the plurality of conductors 5 ... is not mounted in the non-magnetic material core 9 part. This shows the relationship between the slip S and the active power P of the rotor input. The active power P is maximum when the voltage phase is θ = 0 °, and is smaller when 0 ° <θ <180 °. Becomes If the resistance and inductance of the conductors 5 are R and L and the angular frequency of the power supply is ω, the maximum of the active power P appears when S = (R / ωL).

Since the effective power P is proportional to the driving torque of the induction motor 1, the voltage induced on the rotor 8 is adjusted by operating the small motor 35 to rotate the rotating stator 31 with respect to the second stator 25. In addition, the speed of the rotor can be controlled steplessly.

More specifically, a variable speed induction motor that can be set to any desired speed with a wide speed control area and stepless speed control, and can be started with an arbitrary torque.

The rotor of the induction motor configured as described above will be described below with reference to FIG. 1 and FIG.

First, the rotor cores 2 and 3 are generally formed by laminating a silicon steel sheet and an electromagnetic steel sheet. More specifically, the rotor cores 2 and 3 are made of a plurality of silicon steel sheets whose both sides are treated with a phosphoric acid film. It is polymerized to form an integral rotor core. This silicon steel plate is provided with a plurality of conductor insertion holes.

As described above, the rotor cores 2 and 3 are further cast with aluminum, and the rotor cores 2 and 3 are cast by aluminum die-casting to weld the conductor 5 and the short-circuit rings 6, 7 and the conductor for connecting the rotors. The portion 51 is formed integrally at the same time.

Here, the end portion 51 formed by the casting is formed by forming one end portion 51 with respect to a plurality of conductors 5 formed in a plurality of conductor insertion holes by casting. Is done.

The rotor 8 is welded between the cast rotor cores 2 and 3 by welding the ends 51 and the conductors 55 formed on the rotor cores 2 and 3 to form the conductors 55 in communication. Form.

That is, the rotor 8 is easily formed by welding the conductor 55 between the plurality of rotor cores 2 and 3 integrally formed by the aluminum die casting method. Also, if the welding at this time is a method that can be easily welded by a heating operation such as brazing, etc., the manufacture of a rotor of a variable speed induction motor having a plurality of rotor cores which is generally expensive and complicated becomes difficult. This embodiment facilitates this.

Further, an end portion 51 is provided on one end surface of the rotor cores 2 and 3, and a plurality of the rotor conductors 5 are welded to each other with a conductor 55 different from the rotor conductor 5 so that the conductor 55 is welded. A relatively large conductor 55 can be used, and the problem of a variable speed induction motor having a plurality of rotor cores, in which the strength between the rotor cores and the strength of the rotor is concerned, is also solved. For the conductor 55 described here, copper, brass, stainless steel, copper-nickel alloy, iron or the like is used.

〔The invention's effect〕

In view of the above, the production of an induction motor, particularly in the present invention, in which a rotor having a plurality of rotor cores is integrally produced, or the increase or decrease in the number of rotor conductors or the For example, when changes such as shape occur
A plurality of rotor cores are cast to form a short-circuit ring, a rotor conductor and an end integrally, and one of the plurality of rotor cores is formed for one set of a plurality of rotor conductors. By welding a conductor to the end that was made, by forming the conductor in a communicating state between the rotor cores to form an integral rotor,
The strength between the rotor cores can be ensured by the conductors between the rotor cores so that the number and shape of the rotor conductors do not affect the strength of the rotor. Further, the present invention greatly contributes to the manufacture of a rotor of a variable speed induction motor having a plurality of rotor cores which are currently avoided.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a variable speed induction motor according to the present invention, FIG. 2 is a front sectional view as viewed from a section AA in FIG. 1, FIG. 3 is a connection diagram of a stator winding, FIG. FIG. 1 is a partial view related to a rotor in a front sectional view taken along the line BB of FIG. 1, and FIG. 5 is a view showing a relationship between slip of the rotor and active power. DESCRIPTION OF SYMBOLS 1 ... Variable speed induction motor, 2, 3 ... Rotor core, 3 ... Rotor shaft, 5 ... Rotor conductor, 6, 7 ... Short circuit ring, 8 ... Rotor, 10, 11
... Both sides, 12 ... Ventilator, 13 ... Cooling body, 14 ... Machine frame, 1
5,16 ... bearing disc, 17 ... bolt, 19,20 ... cooling impeller, 21 ...
Bearings 22, 23 winding, 25 second stator, 26 sliding bearing, 28 stop ring, 29 driving device, 30 rotating mechanism, 31 rotating stator, 33 gear, 35 Small motor, 36
… Drive gear, 37… opening, 38… solenoid, 39… exhaust port, 40… vent port, 52… shield plate, 66… space section, 67… ventilator, 68… vent port, 69… exhaust port, 70… Blaster, 71… Windmill,
72: motor, 73: blower, 74A: air inlet, 74B: air outlet, r: resistance material.

Claims (4)

(57) [Claims] A plurality of conductors mounted on each of a plurality of rotor cores mounted on the same rotating shaft at arbitrary intervals to form an integral rotor; A plurality of stators are arranged in a machine frame on an outer peripheral portion facing the plurality of rotor cores, and the plurality of conductors are disposed between the plurality of rotor cores not facing the plurality of stators. Short-circuiting occurs via a resistance material, and induced in a conductor portion of the rotor facing one of the plurality of stators in relation to at least one of the plurality of stators. And a voltage shifter for generating a phase difference between a voltage to be induced and a voltage induced in a corresponding conductor portion of the rotor facing the other stator. A plurality of conductors mounted on each of the rotor cores are The rotor of the variable-speed induction motor, characterized in that coupled to the communication form by separate conductors between A. 2. A plurality of conductors provided in each of the plurality of rotor cores, wherein a plurality of adjacent conductors are set as one set for each arbitrary number, and the plurality of sets are provided. The rotor of a variable speed induction motor according to claim 1, wherein the conductors are connected to each other between the rotor cores by different conductors. 3. The rotor for a variable speed induction motor according to claim 1, wherein said connection is welding including brazing. 4. The variable speed induction motor according to claim 1, wherein the conductor between the rotor cores is made of a different material from a plurality of conductors mounted on the rotor core. Rotor.