WO2022064820A1

WO2022064820A1 - Rotor

Info

Publication number: WO2022064820A1
Application number: PCT/JP2021/026671
Authority: WO
Inventors: 和雄西濱; 敦阿部; 高広竹田; 健央三石
Original assignee: 株式会社日立産機システム
Priority date: 2020-09-25
Filing date: 2021-07-15
Publication date: 2022-03-31
Also published as: JP2022054355A; TW202213916A; JP7419205B2; TWI806115B

Abstract

This rotor has a rotor conductor, wherein the rotor conductor has: a first region in which the width of the rotor conductor in the circumferential direction decreases toward the inner circumferential side of the rotor conductor; and a second region which continues into the inner circumferential side of the first region and in which the width of the rotor conductor in the circumferential direction increases toward the inner circumferential side of the rotor conductor. When the distance from the outer circumferential side edge of the rotor conductor to the inner circumferential side edge of the rotor conductor is denoted by h0, the distance from the outer circumferential side edge of the rotor conductor to the outer circumferential side edge of the first region is denoted by h1, the distance from the outer circumferential side edge of the rotor conductor to the inner circumferential side edge of the second region is denoted by h2, and a constant N is a constant calculated on the basis of the depth of eddy current penetrating into the rotor conductor at a rotational speed at which a torque drop occurs during start-up, the rotor conductor satisfies the relationship of h1/h0 < N < h2/h0.

Description

Rotor

The present invention relates to a rotor.

The squirrel-cage induction motor can be started by directly turning on the commercial power, but the torque during starting is not a constant value, and a drop occurs at a certain rotation speed, which may cause stagnation of acceleration. A rotor structure is known that improves the torque characteristics during starting of a cage induction motor.

For example, in the rotor of the cage induction motor described in Patent Document 1, a plurality of rotor conductors made of a material having a sequentially higher resistance value from the outer peripheral side and a storage hole (in which the rotor conductors are arranged) are arranged in the rotor. A slit is provided to connect the rotor slot) and the accommodating hole (rotor slot).

The rotor of the cage-shaped induction motor described in Patent Document 2 is located on the outer peripheral surface side of the rotor core with respect to the first slot and the first slot, and is connected to the first slot. It has two slots, and the first slot is arranged on the side opposite to the outer peripheral surface side and the second slot is arranged on the outer peripheral surface side with respect to the skin depth of the current drive frequency component.

Japanese Unexamined Patent Publication No. 6-205570 WO2019 / 244238A1 Gazette

The rotor of the cage-type induction motor of Patent Document 1 suppresses the drop in torque that occurs during starting, but the radial height and circumferential width of the slit depend on the material and shape of the rotor conductor and the frequency of the power supply. It is necessary to make appropriate adjustments.

The rotor of the cage-type induction motor of Patent Document 2 can improve the drive efficiency while increasing the starting torque, but the positions where the first slot and the second slot are arranged are determined by the material of the rotor conductor and the position. It is necessary to adjust appropriately according to the drive frequency (power supply frequency).

An object of the present invention is to suppress a drop in torque that occurs during starting while keeping the size ratio of the rotor conductor constant without adjusting the dimensions of the rotor conductor according to the material, shape, and power supply frequency. , To provide a rotor.

A preferred example of the present invention is a rotor having a rotor conductor.
The rotor conductor is
A first portion where the circumferential width of the rotor conductor decreases toward the inner peripheral side of the rotor conductor, and
It has a second portion that is continuous with the inner peripheral side of the first portion and whose circumferential width of the rotor conductor increases toward the inner peripheral side of the rotor conductor.
The distance from the outer peripheral end of the rotor conductor to the inner peripheral end of the rotor conductor is h0.
The distance from the outer peripheral end of the rotor conductor to the outer peripheral end of the first portion is h1.
Let h2 be the distance from the outer peripheral end of the rotor conductor to the inner peripheral end of the second portion.
The constant N is a constant calculated based on the depth of the eddy current penetrating the rotor conductor at the rotation speed at which the torque drops during startup.
The rotor conductor is
It is a rotor that satisfies the relationship of h1 / h0 <N <h2 / h0.

According to the present invention, it is possible to suppress a drop in torque that occurs during starting while keeping the size ratio of the rotor conductor constant without adjusting the dimensions of the rotor conductor according to the material, shape, and power supply frequency. ..

It is a cage type induction motor and a partially enlarged view thereof as Example 1. FIG. It is a figure which shows the equivalent circuit of a squirrel-cage induction motor. It is a figure which shows the coefficient which shows the influence of the skin effect. It is a figure which shows the rotation speed (ξ) in which a drop of torque occurs. This is the result of a computer experiment of starting torque. It is a drive system for a squirrel-cage induction motor. It is a figure which shows one slot of the rotor of the cage type induction motor as Example 4. FIG. It is a figure which shows one slot of the rotor of the cage type induction motor as Example 5. FIG. It is a figure which shows one slot of the rotor of the cage type induction motor as Example 6. It is a figure which shows one slot of the rotor of the cage type induction motor as Example 7. It is a figure which shows one slot of the rotor of the cage type induction motor as Example 8. It is a figure which shows one slot of the rotor of the cage type induction motor as Example 9.

Hereinafter, examples will be described with reference to the drawings.

Example 1 will be described using a double cage rotor, which is an example of a rotor of a cage induction motor. The left side of FIG. 1 is a diagram showing a main part of a squirrel-cage induction motor, and the right side of FIG. 1 is an enlarged view of one slot of a rotor. The cage-shaped induction motor of the first embodiment is a rotary electric machine in which the stator 1 and the rotor 5 face each other in the radial direction R with a gap 10 interposed therebetween.

The stator 1 includes a stator core 2 and a stator winding 4 wound around a stator slot 3 formed in the stator core 2.

The rotor 5 includes a rotor core 6, a rotor conductor 8 arranged in a rotor slot 7 formed in the rotor core 6, and a shaft 9 arranged on the inner peripheral side of the rotor core 6.

As shown on the right side of FIG. 1, in the rotor conductor 8 extending in the radial direction R, the width of the circumferential direction X of the rotor conductor 8 becomes smaller toward the inner peripheral side of the rotor conductor 8 first portion 81. And a second portion 82 which is continuous with the inner peripheral side of the first portion 81 and whose circumferential width of the rotor conductor 8 increases toward the inner peripheral side of the rotor conductor 8. The inner peripheral side is the lower side in the figure on the right side of FIG.

In the rotor conductor 8 including the first portion 81 and the second portion 82, the distance from the outer peripheral end of the rotor conductor 8 to the inner peripheral end of the rotor conductor 8 is h0, and the rotor conductor 8 has a distance of h0. When the distance from the outer peripheral end to the outer peripheral end of the first portion 81 is h1, and the distance from the outer peripheral end of the rotor conductor 8 to the inner peripheral end of the second portion 82 is h2. In addition, the relationship of h1 / h0 <N <h2 / h0 (N is a constant) is satisfied. Here, the constant N is calculated based on the depth of the eddy current penetrating the rotor conductor 8 at the rotation speed at which the torque drops during startup. Further, the outer peripheral side is the upper side in the figure on the right side of FIG. 1.

The rotor conductor 8 is formed by press-fitting, for example, aluminum into the rotor slot 7 by a die casting method. Therefore, the rotor conductor 8 has an integral structure without being divided by a portion (for example, a slit) other than aluminum in the rotor slot 7. However, bubbles generated by die casting may be generated in the rotor conductor 8.

In the first embodiment, the double cage rotor is provided with a first portion 81 and a second portion 82. That is, the rotor conductor 8 includes a third portion 83 having a width in the circumferential direction of the rotor conductor 8 smaller than the outer peripheral end of the first portion 81 on the outer peripheral side of the first portion 81. A fourth portion 84 is provided, which is connected to the outer peripheral side of the portion 83 of 3 and whose circumferential width of the rotor conductor 8 increases toward the outer peripheral side of the rotor conductor 8.

FIG. 2 is a diagram showing an equivalent circuit of a squirrel-cage induction motor. Using the equivalent circuit of the squirrel-cage induction motor, the relational expression between the torque and the equivalent circuit constant is derived.

V is the phase voltage (V), I2'is the secondary current (A), r1 is the primary resistance (Ω), r2'is the secondary resistance (Ω), xM is the exciting reactance (Ω), and rM is the iron loss resistance (rM). Ω), x1 is the primary leakage reactance (Ω), x2'is the secondary leakage reactance (Ω), and s is the slip (pu).

The secondary input P2 (W) is represented by the following (Equation 1).
P2 = 3 x ^I2'2 x r2' / s (Equation 1)

The secondary copper loss W2 (W) is expressed by the following (Equation 2).
W2 = 3 x I2'2 x r2'(Equation ² )

The output Pout (W) is a value obtained by subtracting the secondary copper loss from the secondary input, and is expressed by the following (Equation 3).
Pout = P2-W2
= 3 × I2'2 × r2' / s － 3 × ^{I2' 2} ^× r2'
= 3 × ^I2'2 × r2'(1 / s － 1)
= 3 × ^I2'2 × r2' (1 － s) / s (Equation 3)

The torque T (N · m) is the quotient obtained by dividing the output by the angular rotation speed ω (rad / sec) of the rotor, and is expressed by the following (Equation 4).
T = Pout / ω
= Pout / (2πN / 60)
= Pout / (2πNs (1-s) / 60)
= (3 × ^I2'2 × r2' (1 － s) / s) / (2πNs (1 － s) / 60)
= (3 x ^I2'2 x r2' / s) / (2πNs / 60)
= (90 x ^I2'2 x r2' / s) / (πNs)
∝ ^I2'2 × (r2' / s) (Expression 4)
Here, N: rotational speed (r / min), Ns: synchronous speed (r / min)
In the range of slip s that improves the torque drop, I2'is approximately inversely proportional to x1 + x2'. Therefore, the proportional relationship of the torque T is expressed by the following (Equation 5).
T ∝ (r2'/ s) / (x1 + x2') ² (Equation 5)

FIG. 3 is a diagram showing a coefficient showing the influence of the skin effect. The vertical axis of FIG. 3 illustrates φ1 of (Equation 8) and φ2 of (Equation 9), which are coefficients representing the influence of the skin effect, and the unit is (p.u.). The horizontal axis of FIG. 3 is ξ (the reciprocal ratio of the equivalent rotor conductor heights), and the unit is (p.u.).

In the range of slip s that improves the drop in torque, the depth of the eddy current that penetrates the rotor conductor 8 becomes shallower than h0 of the rotor conductor 8 due to the skin effect. Considering the influence of the skin effect, the secondary resistance r2'and the leak reactance x are expressed by the following (Equation 6) and (Equation 7).

r2'= φ1 × r2'dc (Equation 6)
x = x1 + x2'
= φ2 × xdc × K2 + xdc × (1 － K2)
= ((φ2-1) K2 + 1) × xdc (Equation 7)
φ1 = ξ (sinh (2ξ) + sin (2ξ)) / (cosh (2ξ) － cos (2ξ)) (Equation 8)
φ2 = 3 (sinh (2ξ) － sin (2ξ)) / (cosh (2ξ) － cos (2ξ)) / (2ξ) (Equation 9)
ξ = α × h0 (Equation 10)
α = 2π (10 ^-7 × sf / ρ) ^0.5 (Equation 11)
Here,
φ1, φ2: Coefficient representing the effect of skin effect (pu)
r2'dc: Secondary resistance with zero slip (Ω)
xdc: Leakage reactance with zero slip (Ω)
K2: Ratio of secondary slot leakage to total leakage reactance (pu)
ξ: Reciprocal ratio of equivalent rotor conductor heights (pu)
α: Number representing the depth of the epidermis (1 / m)
h0: Rotor conductor height (m)
s: slip (pu)
f: Power frequency (Hz)
ρ: resistivity of rotor conductor (Ω ・ m)

The horizontal axis ξ in FIG. 3 is the reciprocal ratio of the rotor conductor heights that are electromagnetically equivalent when the skin effect is taken into consideration. As in (Equation 11), when the rotation speed is high (slide s is small), α is small, and as in (Equation 10), when α is small, ξ is small. Similarly, when the rotation speed is low, ξ is large.

That is, the equivalent rotor conductor height decreases as the rotation speed decreases and increases as the rotation speed increases. When the rotation speed is equal to the synchronization speed (slip is 0), α is 0 as in (Equation 11), and if α is 0 as in (Equation 10), ξ is 0. When ξ is 0, the coefficients φ1 and φ2 representing the influence of the skin effect are 1, indicating a state in which there is no influence of the skin effect.

FIG. 3 shows a case where the resistance ρ of the rotor conductor is uniform in the rotor conductor 8, and the rotor is, for example, like the rotor of the cage induction motor described in Patent Document 1. This does not apply when a plurality of rotor conductors made of a material having a sequentially higher resistance value are provided from the outer peripheral side, or when a slit for connecting the rotor slots is provided.

The rotor conductor 8 is made of the same material (aluminum), and has an integral structure in the rotor slot 7 without being divided by a portion other than aluminum (for example, a slit), and has a resistivity ρ of the rotor conductor. Is uniform in the rotor conductor 8.

FIG. 4 is a diagram showing a rotation speed (ξ) at which a drop in torque occurs. It is the relationship between the power n (ξ) (vertical axis) and ξ (horizontal axis) when the torque T is proportional to the power of ξ. We will derive ξ at the rotational speed at which the torque drops.

Substituting (Equation 6) and (Equation 7) into (Equation 5), the proportional relationship of the torque T is expressed by the following (Equation 12).
T ∝ (r2'/ s) / (x1 + x2') ²
∝ (φ1 / ξ ² ) / ((φ2-1) K2 + 1) ² (Equation 12)
Assuming that the torque T in (Equation 12) is proportional to the power of ξ, the proportional relationship of the torque T is expressed by the following (Equation 13).
T ∝ ξ ^{n (ξ)} (Equation 13)
When n (ξ) in (Equation 13) is a positive number, the torque T decreases as the rotation speed increases (decrease in ξ), and when n (ξ) is a negative number, the rotation speed increases (ξ). (Decrease), the torque T increases. Therefore, if there is a range in which n (ξ) in (Equation 13) is a positive number, the torque will drop.

As shown in FIG. 4, when the ratio K2 of the secondary slot leakage to the total leakage reactance becomes large, n (ξ) may become positive. That is, when the ratio K2 of the secondary slot leakage to the total leakage reactance becomes large, the torque tends to drop.

In Fig. 4, when K2 is 0.5 or more, n (ξ) may become positive. That is, when K2 becomes 0.5 or more, the torque drops. When K2 is 0.5, n (ξ) is maximum when ξ is 2.2. K2 is at most 1, and when K2 is 1, n (ξ) is maximum when ξ is 2.6.

Thus, when K2 is 0.5 to 1.0 and ξ is 2.2 to 2.6, n (ξ) is large (the torque decrease is large). That is, if the torque at the rotation speed at which ξ is 2.2 to 2.6 is given priority and increased, the drop in torque can be effectively improved.
When the rotor conductor height h0 is 1.0, the skin depth δ is expressed by the following (Equation 14).
δ = 1 / (αh0) = 1 / ξ (Equation 14)
When K2 is 0.5 to 1.0 and ξ is 2.2 to 2.6, the decrease in torque becomes large, and when ξ is 2.2, the skin depth is 0.45 when ξ is substituted for 2.2 in (Equation 14). When ξ is 2.6, it is 0.38, and when ξ is 2.4 on average, it is 0.42.

The constant N (skin depth δ) calculated based on the depth of the eddy current penetrating the rotor conductor at the rotation speed at which the torque drops during startup is in the range of 0.38 or more and 0.45 or less. As a typical example of the range, the case where the constant N (skin depth δ) is 0.42 will be described.

From the above, in this embodiment, in order to preferentially increase the torque at the rotation speed at which the skin depth δ is 0.42, the end on the outer peripheral side of the rotor conductor 8 to the end on the inner peripheral side of the rotor conductor 8 A constriction is provided at a position 0.42 times the distance h0 to effectively increase r2'to improve the torque drop.

In this embodiment, the torque drop can be improved by providing a constriction at a position 0.42 times that of h0, and this dimensional ratio can be determined when the material and shape of the rotor conductor and the power supply frequency are changed. However, it may be kept at a constant value without adjustment.

On the other hand, in general, in order to improve the torque characteristics during starting, for example, as in Patent Document 1, the radial height and the circumferential width of the slit are set according to the material and shape of the rotor conductor and the frequency of the power supply. , Need to be adjusted appropriately. Further, as in Patent Document 2, it is necessary to appropriately adjust the positions where the first slot and the second slot are arranged according to the material of the rotor conductor and the drive frequency (power supply frequency). From Patent Document 1 and Patent Document 2, even when the material and shape of the rotor conductor and the power supply frequency are changed, the torque characteristics during starting are maintained at a constant value without adjusting the dimensional ratio of the rotor conductor. There is no idea of this example that it can be improved.

FIG. 5 is a computer experiment result of the starting torque. In the case of the first embodiment of FIG. 1, when both h1 / h0 and h2 / h0 are smaller than 0.42 (when the constriction position is shallow on the outer peripheral side), both h1 / h0 and h2 / h0 are from 0.42. It also indicates when the size is large (when the constriction position is deep on the inner peripheral side) and when the constriction is not provided. The target machine has 4 poles, the rotor conductor 8 is assumed to be aluminum, the resistivity ρ is 3.65 × 10 ^-8 Ω · m, the rotor conductor height h0 is 51 mm, and the power supply frequency f is 50 Hz. The torque is rated at 100%.

In this embodiment, the drop in torque is improved, the torque is larger on the high rotation speed side than when the constriction position is shallow on the outer peripheral side, and the torque is larger on the low rotation speed side than when the constriction position is deep on the inner peripheral side. Is getting bigger. As a result, in this embodiment, the minimum torque value is large in both the case where the constriction position is shallow on the outer peripheral side and the case where the constriction position is deep on the inner peripheral side.

Example 2 will be described. The points common to the first embodiment will be omitted. Most cage induction motors are used in the range of rotational speeds from 0 to synchronous speeds. The slip s is 1 when the rotation speed is 0, and 0 when the rotation speed is equal to the synchronization speed.

Therefore, even if the slip s at which the torque drop occurs is made larger than 1, the torque drop can be suppressed and can be derived as follows.
From (Equation 10), α is represented by the following (Equation 15).
α = ξ / h0 (Equation 15)
From (Equation 11), the slip s is represented by the following (Equation 16).
s = ρα ² / (4π ² × 10 ^-7 × f) (Equation 16)
Substituting (Equation 15) into (Equation 16), it is expressed by the following (Equation 17).
s = ρξ ² / (4π ² × 10 ^-7 × f × h0 ² ) (Equation 17)
When the slip is greater than 1, (Equation 17) is expressed by the following (Equation 18).
1 <ρξ ² / (4π ² × 10 ^-7 × f × h0 ² ) (Equation 18)
When h0 is derived from (Equation 18), it is expressed by the following (Equation 19).
h0 <ρ ^0.5 × ξ / (2π × 10 ^-3.5 × f ^0.5 ) (Equation 19)
The ξ at which the torque drop occurs is 2.2 to 2.6, and when 2.4, which is the average value thereof, is substituted into (Equation 19), it is expressed by the following (Equation 20).
h0 <1200 (ρ / f) ^0.5 (Equation 20)

Therefore, according to (Equation 20), the torque is obtained by adjusting the rotor conductor height h0 according to the resistivity ρ of the rotor conductor 8 whose unit is Ω · m and the power supply frequency f whose unit is Hz. The slip s at which the dip occurs can be made larger than 1. As a result, the drop in torque can be suppressed.

FIG. 6 is a diagram showing a drive system of a squirrel-cage induction motor as the third embodiment. The points common to the above examples will be omitted.

The commercial voltage and frequency are directly input from the power supply 101 to the cage induction motor 100 and started. The cage induction motor 100 is mechanically connected to the load equipment 102.

The squirrel-cage induction motor can be started by directly turning on the commercial power supply, but the current during starting is as large as 6 to 10 times the rated current, and the capacity of the power supply equipment is the current at the time of starting. It depends on the starting time. By using the squirrel-cage induction motor according to the present invention, the drop in torque can be suppressed, the starting time can be shortened, and the capacity of the power supply equipment can be reduced.

FIG. 7 is a diagram showing one slot of the rotor of the squirrel-cage induction motor as the fourth embodiment. The points common to the above examples will be omitted.

The positions of the first portion 81 and the second portion 82 of the rotor conductor 8 are the boundary positions between the first portion 81 and the second portion 82 (the circumferential width of the first portion 81 and the second portion 82). Is not always required to be 0.42 times the rotor conductor height h0). For example, even if the second portion 82 has a position of 0.42 times as shown in FIG. 7 (a), the first portion 81 has a position of 0.42 times as shown in FIG. 7 (b). There may be a position.

Further, the rotor conductors 8 shown in FIGS. 7 (a) and 7 (b) may be arranged alternately in the circumferential direction. By arranging them alternately, the effect of suppressing the drop in torque can be obtained in a wider rotation speed range.

FIG. 8 is a diagram showing one slot of the rotor of the squirrel-cage induction motor as the fifth embodiment. The points common to the above examples will be omitted.

The rotor conductor 8 has a section in which the width in the circumferential direction is constant between the end on the inner peripheral side of the first portion 81 and the end on the outer peripheral side of the second portion 82. Since the section with a small width in the circumferential direction becomes large, the effect of suppressing the drop in torque is enhanced.

FIG. 9 is a diagram showing one slot of the rotor of the squirrel-cage induction motor as the sixth embodiment. The points common to the above examples will be omitted.

At the outer peripheral end of the first portion 81 and the inner peripheral end of the second portion 82, the rotor conductor 8 has a stepwise width in the circumferential direction. Since the section having a small width in the circumferential direction becomes larger than the gradual change, the effect of suppressing the drop in torque is enhanced.

FIG. 10 is a diagram showing one slot of the rotor of the squirrel-cage induction motor as the seventh embodiment. The points common to the above examples will be omitted.

Example 7 will be described using a convex rotor, which is an example of a rotor of a cage induction motor. In Example 7, the convex rotor is provided with a first portion 81 and a second portion 82. That is, the rotor conductor 8 includes a third portion 83 having a circumferential width of the rotor conductor 8 smaller than the outer peripheral end of the first portion 81 on the outer peripheral side of the first portion 81. ..

Further, it is provided with a seventh portion 87 which is continuous with the inner peripheral side of the third portion and whose circumferential width of the rotor conductor 8 increases toward the inner peripheral side of the rotor conductor.

If the circumferential width of the rotor conductor 8 is reduced, the current when the slip is large is reduced. Since the position where the circumferential width of the rotor conductor 8 is reduced is larger toward the outer peripheral side of the rotor conductor 8, the effect is greater. By providing the portion 82 of 2, the current when the slip is large is reduced.

FIG. 11 is a diagram showing one slot of the rotor of the squirrel-cage induction motor as the eighth embodiment. The points common to the above examples will be omitted.

Example 8 will be described using a diamond-shaped rotor, which is an example of a rotor of a squirrel-cage induction motor. In Example 8, the diamond-shaped rotor is provided with a first portion 81 and a second portion 82. That is, the rotor conductor 8 includes a fifth portion 85 on the outer peripheral side of the first portion 81 in which the width in the circumferential direction of the rotor conductor 8 gradually decreases toward the outer peripheral side. The circumferential width at the outer peripheral end of the fifth portion 85 is smaller than the circumferential width at the outer peripheral end of the first portion 81.

If the circumferential width of the rotor conductor 8 is reduced, the current when the slip is large is reduced. Since the position where the circumferential width of the rotor conductor 8 is reduced is larger toward the outer peripheral side of the rotor conductor 8, the effect is greater. By providing the portion 82 of the above, the current when the slip is large is reduced.

FIG. 12 is a diagram showing one slot of the rotor of the squirrel-cage induction motor as the ninth embodiment. The points common to the above examples will be omitted.

Example 9 will be described using an eggplant-shaped rotor, which is an example of a rotor of a cage-shaped induction motor. In Example 9, the eggplant-shaped rotor is provided with a first portion 81 and a second portion 82. That is, the rotor conductor 8 includes a sixth portion 86 on the outer peripheral side of the first portion 81 in which the width in the circumferential direction of the rotor conductor 8 gradually increases toward the outer peripheral side.

The circumferential width at the outer peripheral end of the sixth portion 86 is larger than the circumferential width at the outer peripheral end of the first portion 81.

If the width of the rotor conductor 8 in the circumferential direction is reduced, the power factor during steady operation with small slippage decreases. The first portion 81 and the second portion 82 are provided on the squirrel-cage rotor having a smaller circumferential width section of the rotor conductor 8 than the double cage rotor, the convex rotor, and the rhombic rotor. As a result, the power ratio when the slip is small is improved.

Although the examples have been described above, the examples are not limited to the above-mentioned examples, and various modifications are included. For example, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

1 ... stator, 2 ... stator core, 3 ... stator slot, 4 ... stator winding, 5 ... rotor, 6 ... rotor core, 7 ... rotor slot, 8 ... rotor conductor, 9 ... shaft 10 ... Gap, 100 ... Cage-shaped induction motor, 101 ... Power supply, 102 ... Load equipment

Claims

A rotor with a rotor conductor,
The rotor conductor is
A first portion where the circumferential width of the rotor conductor decreases toward the inner peripheral side of the rotor conductor, and
It has a second portion that is continuous with the inner peripheral side of the first portion and whose circumferential width of the rotor conductor increases toward the inner peripheral side of the rotor conductor.
The distance from the outer peripheral end of the rotor conductor to the inner peripheral end of the rotor conductor is h0.
The distance from the outer peripheral end of the rotor conductor to the outer peripheral end of the first portion is h1.
Let h2 be the distance from the outer peripheral end of the rotor conductor to the inner peripheral end of the second portion.
The constant N is a constant calculated based on the depth of the eddy current penetrating the rotor conductor at the rotation speed at which the torque drops during startup.
The rotor conductor is
A rotor that satisfies the relationship h1 / h0 <N <h2 / h0.
In the rotor according to claim 1,
The rotor conductor is made of the same material
The N is a rotor in the range of 0.38 or more and 0.45 or less.
In the rotor according to claim 1,
The rotor conductor is made of the same material
The rotor whose N is 0.42.
In the rotor according to claim 1,
The rotor conductor is
Between the inner peripheral end of the first portion and the outer peripheral end of the second portion,
A rotor having a section having a constant width in the circumferential direction.
In the rotor according to claim 1,
The rotor conductor is
At the outer peripheral end of the first portion and the inner peripheral end of the second portion
A rotor whose width in the circumferential direction changes in a staircase pattern.
In the rotor according to claim 1,
The rotor conductor is
A third portion whose circumferential width of the rotor conductor is smaller than the outer peripheral end of the first portion on the outer peripheral side of the first portion.
A rotor having a seventh portion that is continuous with the inner peripheral side of the third portion and whose circumferential width of the rotor conductor increases toward the inner peripheral side of the rotor conductor.
In the rotor according to claim 1,
The rotor conductor is
It has a fifth portion on the outer peripheral side of the first portion, in which the width in the circumferential direction of the rotor conductor gradually decreases toward the outer peripheral side.
The width in the circumferential direction at the outer peripheral end of the fifth portion is
A rotor smaller than the width in the circumferential direction at the outer peripheral end of the first portion.
In the rotor according to claim 1,
The rotor conductor is
It has a sixth portion on the outer peripheral side of the first portion, in which the width in the circumferential direction of the rotor conductor gradually increases toward the outer peripheral side.
A rotor whose circumferential width at the outer peripheral end of the sixth portion is larger than the circumferential width at the outer peripheral end of the first portion.
In the rotor according to claim 1,
When the resistivity of the rotor conductor whose unit is Ω · m is ρ and the power frequency whose unit is Hz is f
The h0 is
A rotor that satisfies the relationship of h0 <1200 (ρ / f) 0.5 .
In the rotor according to claim 1,
Has a rotor core,
The rotor conductor is
Arranged in the rotor slot formed in the rotor core,
A rotor having a shaft on the inner peripheral side of the rotor core.
The cage-shaped induction motor having the rotor according to claim 1.
A drive system including the squirrel-cage induction motor according to claim 11, a power source, and load equipment.