JP2001200333A - Rotor shaft for rotary electric machine and rotary electric machine using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor shaft for a rotary electric machine provided with high strength, high toughness and high magnetic properties and to provide a large capacitance rotary electric machine and a large capacitance generator using the same. SOLUTION: This high strength low alloy steel has a composition containing, by weight, 0.15 to 0.30% C, <=0.1% Si, 0.05 to 1% Mn, 3.0 to 5.0% Ni, 2.05 to 3,0% Cr, 0.1 to 1.0% Mo, 0.03 to 0.35% V, and the balance substantial Fe, or containing 0.15 to 0.35% C, <=0.1% Si, 0.05 to 1% Mn, 3.25 to 5.0% Ni, 1.5 to 3.5% Cr, 0.1 to 1.0% Mo, 0.03 to 0.35% V, and the balance substantial Fe, and in which the above (Ni/Cr) ratio is 1.2 to 1.81, and the rotary shaft for a rotary electric machine uses the same. In this way, a large capacitance generator with the capacitance of 900 MVA or more and a motor with the rotating speed of 5,000 rpm or more can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel rotor shaft for a rotating electric machine, a large-capacity rotating electric machine using the same, and a large-capacity generator.

[0002]

2. Description of the Related Art As a rotor shaft material of a turbine generator up to a capacity of 800 MVA, ASTM standard material Ni-Cr-
Mo steel (A469-88, Classes 6 to 8) is used. In recent years, from the viewpoint of energy diversification, there has been a trend to increase the capacity of turbine generators due to a shift to coal-fired power, which is an alternative to oil, and a demand for effective utilization of a power supply site area.

[0003] With the increase in capacity of the turbine generator, the operating conditions of the rotor shaft have become severe, and the above-mentioned current AST
With M standard materials, the strength has become insufficient.

In general, as the strength is increased, the toughness tends to decrease. Therefore, the emergence of a rotor shaft material having higher strength and toughness than the currently used material is desired.

[0005] ASTM standard class 6-8 is 0.28% C
Below, Mn 0.60% or less, P 0.015% or less, S0.01
5% or less, Si 0.15 to 0.30%, Ni 3.25 to 4.
00%, Cr 1.25 to 2.00%, Mo 0.30 to 0.6
0%, V 0.05 to 0.15%, balance substantially consisting of Fe, class 8 having the highest strength, tensile strength of 84 kg / mm ² or more, 0.02% proof stress 70.4 kg / mm ² or more, elongation of 16% or more, squeezing ratio of 45% or more, 50% fracture appearance transition temperature 4 ° C. or less and the like are defined.

Japanese Patent Publication No. 47-25248 discloses C0.14.
-0.20%, Si 0.05-0.4%, Mn 0.1-0.1.
6%, Ni 1.5 to 2.8%, Cr 0.75 to 1.8%, M
o 0.1-0.5%, V 0.01-0.12% and balance Fe
A low alloy steel for a generator rotor shaft consisting of:

[0007] JP-B-60-230965 discloses C0.13.
0.30%, Si 0.10% or less, Mn 0.60-2.
00%, P0.010% or less, Cr 0.40 to 2.00
%, Ni 0.20-2.50%, Mo 0.10-0.50
%, V 0.05 to 0.15%, Al 0.005 to 0.04
%, N 0.0050-0.0150%, Ni + 2Mn + 2
A low alloy steel for a turbine generator shaft composed of 4 to 8% of Cr and the balance of Fe is shown.

[0008]

As a rotor shaft material of a generator having a capacity of 900 MVA or more, a tensile strength of 93 kg is used.
/ Mm ² , 0.02% Yield strength of 74 kg / mm ² or more, mechanical properties of 0 ° C. or less of fracture transition temperature (hereinafter abbreviated as FATT) and magnetic properties of 990 AT / cm or less at 21,000 gauss are required. You.

Further, as a rotor shaft material of a 1200 MVA class generator, a tensile strength of 100 kg / mm ² or more and 130
The rotor shaft material of the 0MVA class generator is required to have a tensile strength of 104 kg / mm ² or more.

In the case of ASTM standard materials (A469-Class 8) and those disclosed in the prior art, the tensile strength is ≧ 84.1 k.
g / mm ² , 0.02% proof stress ≧ 70.4 kg / mm ² , FATT ≦
The strength and toughness are insufficient for a rotor shaft material for a generator having a temperature of 4 ° C. and 900 MVA or more, and safety against breakage cannot be secured.

Further, conventionally, when the strength is increased, the toughness decreases,
A product satisfying both strength and toughness was not obtained.

An object of the present invention is to provide a rotor shaft for a rotating electric machine having high strength, high toughness and high magnetic properties, a large-capacity rotating electric machine using the same, and a large-capacity generator.

[0013]

SUMMARY OF THE INVENTION The present invention provides a C
0.15 to 0.30%, Si 0.1% or less, Mn 0.05
-1%, Ni 3.0-5.0%, Cr 2.05-3.0%,
Mo 0.1 to 1.0%, V 0.03 to 0.35%, and the balance being substantially Fe.

The present invention relates to a C.sub.0.15 to 0.35 by weight.
%, Si 0.1% or less, Mn 0.05-1%, Ni 3.2
5 to 5.0%, Cr 1.5 to 3.5%, Mo 0.1 to 1.0
%, V 0.03 to 0.35% and the balance substantially Fe, and the (Ni / Cr) ratio is 1.2 to 2.3.

[0015] The present invention relates to a method for producing C0.15 to 0.30 by weight.
%, Si 0.3% or less, Mn 0.05-1%, Ni 3.0
-5.0%, Cr 2.05-3.0%, Mo 0.1-1.0
%, V0.03 to 0.35%, A10.006% or less, and the balance is substantially Fe.

The present invention relates to the Ni-Cr-Mo-V described above.
A rotor shaft for a rotating electric machine, characterized by having a room temperature tensile strength of steel of 93 kg / mm ² or more, a 50% fracture surface transition temperature of 0 ° C. or less, and a tempered bainite structure.

[0017] The present invention relates to the above steel, wherein a group IIa element and a group IIIa
It contains 0.001 to 0.1% of at least one group a element.

The present invention further relates to the above steel by further adding a group IVa element, N
It contains at least one element of b, Ta and W in an amount of 0.2% or less.

According to the present invention, the susceptibility 990 at 21 kG is used.
It is preferably at most AT / cm, and more preferably is made of a Ni-Cr-Mo-V alloy steel having the above-mentioned composition and having a tempered bainite structure.

The present invention relates to a C.sub.0.15 to 0.30 by weight.
%, Si 0.1 to 0.3% or less, Mn 0.05 to 0.5%,
Ni 3.25 to 4.5%, Cr 2.05 to 2.60%, Mo
0.25 to 0.60%, V 0.05 to 0.20%, Al
0.01% or less, with the balance being substantially Fe, and having a tempered bainite structure.

The rotor shaft for a rotating electric machine having the above-described composition according to the present invention is melted in the atmosphere, subjected to ladle refining, vacuum degassing, and the like, and then poured into a mold to form a mold. It is preferable to perform a hot forging after the ingot after the ingot is melted or further melted in the air and then the electroslag is melted, and then tempered at 800 to 900 ° C., and then tempered at 550 to 650 ° C. for 10 hours or more.

The present invention resides in a rotor shaft for a rotating electric machine having the above-mentioned composition, comprising a body having a slot into which a coil is embedded in the axial direction, a flange for transmitting and receiving power, and a bearing. Room temperature tensile strength 93 kg / mm ²
As described above, the magnetizing force at 0% or less at 50% fracture surface transition temperature and 21 kG is 990 AT / cm or less, the magnetizing force at 20 kG is 400 AT / cm or less, and the body diameter is 1 m.
It is preferable that the length of the trunk is 5.5 to 6.5 times the diameter of the trunk.

In the present invention, the shaft may have a body diameter of 1 m or more and a body length of 5.5 to 6.5 of the body diameter.
Of the high-strength Ni-Cr-Mo-V alloy steel described above, wherein the body diameter D (mm) is equal to or less than a value obtained by adding 1000 mm to 0.2 mm per 1 MVA of the electrical capacity and 0 or less per 1 MVA of the generator capacity. It is preferably at least the value obtained by adding 900 mm to .2 mm.

According to the present invention, the shaft has a body diameter D (mm) of 1 m or more and a body length of 5.5 mm of the body diameter.
It is made of the above-mentioned high-strength Ni-Cr-Mo-V alloy steel which is up to 6.5 times, and the value of (D ² × R ² ) obtained from the relationship with the rotation speed R (rpm) of the shaft is 1. 0 × 10 ^{7 to} 3.0
It is preferable to set the body diameter with respect to the number of rotations so as to be × 10 ⁷ .

The present invention relates to a method for preparing C.sub.0.15 to 0.30 by weight.
%, Si 0.3% or less, Mn 0.05-0.5%, Ni
3.0-5.0%, Cr 2.05-3.5%, Mo0.1-
1.0%, V 0.03 to 0.35%, Al 0.006% or less,
A rotor shaft for a rotating electric machine, wherein the rotor shaft is made of a low alloy steel having a total amount of P, S, Sn, Sb and As of 0.025% or less and the (Ni / Cr) ratio is 1.2 to 2.3.

According to the present invention, a room temperature tensile strength of 93 kg / mm ² or more, a 50% fracture surface transition temperature of 0 ° C. or less, a magnetizing force at 21 kG of 990 AT / cm or less, and a magnetizing force of 20 kG or less.
The aforementioned high-strength and high-toughness Ni—C having a value of not more than 00 AT / cm
It is preferable to use a rotating shaft for a rotating electrical machine, which is constituted by an integral solid shaft made of r-Mo-V alloy steel.

The present invention relates to a C.sub.0.15 to 0.30 by weight.
%, Si 0.01 to 0.05%, Mn 0.05 to 0.5%,
Ni 3.0 to 5.0%, Cr 2.05 to 3.5%, Mo 0.5%.
1 to 1.0%, V 0.03 to 0.35%, Al 0.0005 to
0.006%, total amount of P, S, Sn, Sb and As 0.0
01 to 0.025%, with the balance substantially consisting of Fe.

The present invention is suitable for a large-capacity rotating electric machine having a capacity of 900 MVA or more, comprising a stator composed of a laminated iron core having a coil embedded therein, and a rotor rotating in the stator. A coil is embedded in a shaft body made of a rotor shaft for a rotating electric machine having a diameter of 1 m.
As described above, the trunk length is 5.5 to 6.5 times the trunk diameter, and 3
000 rpm or 360 rpm, and the floor area of the rotating electric machine is 0.08 to 0.12 m ² per 1 MVA of the electric machine capacity.
Are preferred.

According to the present invention, the electric capacity is 900 MVA or more, and the stator current is 19.0 to 24 per 1 MVA of the electric capacity.
A, The stator is directly water-cooled, and the rotor is 1 MVA in electrical capacity
The rotor shaft is cooled at a hydrogen pressure of 0.003 to 0.006 kg / cm ² , and the rotor shaft has a body diameter of 1.0 m or more, and is made of the above-mentioned high-strength Ni-Cr-Mo-V alloy steel. It is preferable to use a capacity rotating electric machine.

According to the present invention, at a rated capacity of 1,120,000 KVA, the stator is directly water-cooled, the rotor is hydrogen-cooled, the rotor body diameter is 1.15 to 1.35 m, and the body length is 5% of the body diameter. It is preferable that the rotation speed is 3.5 to 6.5 times and the rotation speed is 3600 rpm. In particular, 9-1 as the machine size
It is preferably 0 m ³ .

The present invention relates to a method for preparing C 0.15 to 0.30 by weight.
%, Si 0.3% or less, Mn 0.05-0.5%, Ni
3.0-5.0%, Cr 2.05-3.5%, Mo0.1-
1.0%, V 0.03 to 0.35%, Al 0.010% or less,
A rotor shaft for a rotating electric machine, wherein the rotor shaft is made of a low alloy steel having a total amount of P, S, Sn, Sb and As of 0.025% or less and the (Ni / Cr) ratio is 1.2 to 2.3.

[0032]

[Function] C is indispensable for the improvement of strength. Therefore, if the content is less than 0.15%, sufficient hardenability cannot be obtained, a soft ferrite structure is formed at the center of the rotor, and sufficient tensile strength and proof stress are obtained. Can not be obtained. Further, when the content exceeds 0.3%, the toughness is reduced, so that the range of C is 0.15 to 0.3.
%. If the (Ni / Cr) ratio is 1.2 to 2.0, it can be 0.15 to 0.35. In particular, C is preferably in the range of 0.20 to 0.28%.

Conventionally, Si and Mn have been added as deoxidizing materials. However, by using steelmaking techniques such as C deoxidizing method by vacuum ladle refining and electroslag remelting method, a sound rotor can be melted without any particular addition. It can be manufactured. From the viewpoint of preventing temper embrittlement, Si and Mn should be set low, and are limited to 0.1% and 1.0% or less, respectively.
It is preferably 0.05% or less, Mn 0.25% or less, more preferably 0.20% or less. Even when Si is not added, it is contained as an impurity in an amount of 0.019 to 0.1%. Mn is preferably slightly added, and is set to 0.05% or more, more preferably 0.1%.
Above.

Ni is an element indispensable for improving hardenability and improving toughness. If it is less than 3.0%, the effect of improving toughness is not sufficient. On the other hand, a large amount of addition exceeding 5% causes a harmful residual austenite structure to appear, and a uniform tempered bainite structure cannot be obtained. In particular, the range is preferably 3.25% or more, more preferably more than 3.5% and up to 4.5%.

Cr has the effect of improving hardenability and significantly improving toughness. It also has the effect of improving corrosion resistance. Below 1.5% these effects are not enough,
When added in a large amount exceeding 3.0%, a harmful retained austenite structure appears, and a uniform tempered bainite structure cannot be obtained. In particular, 2.05% or more, and 2.05 to 2.6
A range of 0% is preferred.

Mo precipitates fine carbides in crystal grains during the tempering treatment, and has an effect of increasing tensile strength and 0.02% proof stress by a carbide dispersion strengthening action. In addition, it has an effect of suppressing segregation of impurity elements at crystal grain boundaries during tempering, and thus has an effect of preventing temper embrittlement. If the content is less than 0.1%, these effects are not sufficient, and even if added in a large amount exceeding 1.0%, the effects tend to be saturated. In particular,
0.25 to 0.6%, more preferably 0.35 to 0.45%.

V has the effect of precipitating fine carbides at the crystal grain boundaries during the tempering treatment and increasing the tensile strength and 0.02% proof stress by the carbide dispersion strengthening action. If the amount is less than 0.03%, these effects are not sufficient, and if the amount exceeds 0.35%, the effect tends to be saturated. In particular, 0.05 to 0.2
%, More preferably in the range of 0.10 to 0.15%.

Since Al reduces the toughness and magnetic properties,
Should be lower. Reduction of Al has a large effect of improving toughness and magnetic properties. Al is particularly preferred from the viewpoint of securing toughness.
01% is the upper limit. In particular, 0.005% or less is preferable. If Al is eliminated altogether, the strength will be reduced conversely, so from the viewpoint of steelmaking, 0.0005% or more, particularly 0.001% or more is preferable.

Further, there are P, S, Sn, Sb, and As as impurities, and these lower the toughness and the magnetic properties. Therefore, it is necessary to lower these elements. In particular, these elements have a correlation with Si, and it is preferable that the value obtained by multiplying the amount of Si by the total sum of these elements be 30 × 10 ⁻⁴ or less. Particularly, it is preferably 15 × 10 ⁻⁴ or less. Further, the total amount of these elements excluding Si is 0.030% or less, and
025% or less is preferable. It is difficult to eliminate these impurities at all, especially 0.001 as the lower limit of the total amount.
%, And 0.010%.

The (Ni / Cr) ratio is related to the tensile strength, and high strength can be obtained by setting the value to 2.3 or less, more preferably 2.1 or less. When the values are the same, the higher the Ni content, the higher the strength, and the higher the Ni content, the higher the strength. In particular, for a Ni content of 3% or more, (N
The (i / Cr) ratio is preferably 1.2 to 2.3, more preferably 1.2 to 2.0, and even more preferably 1.4 to 1.9.

Group IIa elements (Be, Mg, Ca), IIIa
Group 1 element (Sc, Y, lanthanoid element)
0.1% or less of two or more species. These elements act as a strong deoxidizing agent, and have remarkable effects on improving toughness and magnetic properties. In particular, 0.001 to 0.0
It is preferably set to 5%. These are non-radioactive elements, and radioactive elements are not preferred in handling.

Group IVa elements (Ti, Zr, Hf), Nb,
At least one of the carbide forming elements of Ta and W is 0.2%.
By increasing the content below, the strength is increased without lowering the toughness. In particular, 0.02 to 0.1% is preferable. W is Mo
Since Mo has the same effect as described above, a part of Mo can be replaced with W. Therefore, it is preferable that the Mo + W amount is set to 0.1 to 1.0%, the upper limit of the W amount is set to 0.5%, and the Mo amount is set to half or less of the Mo amount.

The low-alloy steel according to the present invention has a tempered bainite structure and can contain 5% or less of ferrite. However, it is preferable to have an all-bainite structure in terms of strength and toughness.

The low-alloy steel according to the present invention is capable of increasing strength and toughness and improving magnetic properties by remarkably reducing Si impurities. A molten metal is formed by post-vacuum ladle refining. The molten metal is cast in a mold and is formed into a predetermined shape by hot forging. Thereafter, quenching is performed at 800 to 900 ° C, and then tempering is performed at 550 to 650 ° C for 10 hours or more.
The quenching temperature is 30 to 70 ° C. higher than the Ac ₃ point of the steel, and particularly preferably 50 ° C. higher than Ac ₃ . Tempering increases toughness, and is 550 to 650.
° C, especially 560-600 ° C, preferably 10-60 h
It is preferable to hold. After the tempering, the final shape is obtained by the cutting process. However, since the internal stress is generated by the cutting process, the stress relief refining is performed at a temperature lower than the tempering temperature. After forging, homogenization and sintering are performed, performed at a temperature about 50 ° C. higher than the quenching temperature, and then cooled. The cooling rate during quenching is preferably 50 to 150 ° C / h at the center of the shaft. As a result, a bainite structure is obtained, and in particular, a whole bainite structure is obtained.

The Si content is 0.01% of the above-mentioned Al content.
The content can be reduced to 0.1 to 0.3% by the following, and the P, S, Sn, Sb and As amounts are set to 0.025%.
By setting the content below, good characteristics can be obtained even with high Si.

By using the above-mentioned alloy steel, the rotor shaft for the rotating electric machine can be adjusted so that the diameter of the body in which the coil is embedded is 1 unit.
m or more and the body length is 5.5 to 6.5 times the diameter, so that the entire apparatus can be made compact. Rotors with ratios less than 5.5 and greater than 6.5 are not preferred due to their vibration sensitivity. Particularly, 5.6 to 6.0 is preferable.

The diameter of the body must be increased in accordance with the capacity of the generator.
0 mm or less, plus 90 mm to 0.2 mm per MVA
It is preferable that the value be equal to or more than the value obtained by adding 0 mm.

Further, the body diameter D (m) is also set by the rotation speed R (rpm) of the rotor, and the value of (D ² × R ² ) is set to 1.0 × 10 ⁷ or more. It is preferable to set In particular, the upper limit is preferably set to 3.0 × 10 ⁷ . In particular, 1.5 to 2.2 × 10 ⁷ is preferable, and 1.8 to 2.0 × 1 is preferable.
0 ⁷ is good.

In the present invention, the generator and the motor are increased in size due to the increase in capacity. However, as described above, the use of high-strength alloy steel makes it possible to provide a compact device. 0.08-0.1
It can be ² m ² . Since the energy loss can be reduced, the efficiency is further improved. Since the stator current can also be reduced per capacity, it can be set to 19.0 to 24 A per 1 MVA of the motor or generator capacity. In particular, the current per unit capacity can be reduced as the capacity increases. Approximately 19.0 to 20.0 for 2000 MVA capacity
A can do it. At this time, the rotor is cooled by hydrogen, and it is necessary to increase the hydrogen pressure in accordance with the generator output. The pressure is increased from 0.003 to 0.006 kg / MVA.
cm ² · g. In particular, 0.004 to 0.0
05 kg / cm ² · g is preferred.

The present invention is applied to a generator and a motor. Examples of the motor include a synchronous motor, a synchronous generator motor, and an induction synchronous motor. The structures of the motor and the generator are almost the same. In particular, 5000-6000rp as a motor
This is preferable for a high-speed motor having a rotation number of m.

The tensile strength of the rotor shaft in the present invention is preferably at least 93 kg / mm ^2, more preferably at least 100 kg / mm ² , particularly preferably at least 104 kg / mm ² . At the same time, the 50% fracture surface transition temperature is set to 0 ° C or lower, more preferably -50 ° C or lower. The size of the crystal grains is preferably 4 or more in ASTM crystal grain number. Further, as a magnetic property, a magnetic flux density of 21 kG
990AT / cm or less at 20k
The magnetizing force in G is preferably 400 AT / cm or less, and particularly preferably the former is 500 AT / cm or less.

[0052]

EXAMPLES Example 1 Table 1 shows the chemical composition (% by weight) of the test steel. Each sample was ingoted in an amount of 20 kg in a high-frequency melting furnace, and hot forged to a temperature of 850 to 1150 ° C and a thickness of 30 mm and a width of 90 mm. Samples Nos. 2 to 6 and 15 are the materials of the present invention. Sample No. 1 was melted for comparison with the inventive material. No. 1 is a material corresponding to ASTM standard A469-88 class 8 of the generator rotor shaft material, and No. 5 is a high Al steel. These samples were subjected to a heat treatment simulating the conditions at the center of a large rotor shaft of a large capacity generator. First, it was heated to 840 ° C., austenitized, cooled at a rate of 100 ° C./h, and quenched. Then, after heating and holding at 575 to 590 ° C for 32 hours, it was cooled at a rate of 15 ° C / h. The tempering treatment was performed by selecting a temperature at which the tensile strength falls within a range of 100 to 105 kg / mm ² for each sample.

Nos. 7 to 12 are comparative steels at 820.degree.
After quenching at a rate of 100 ° C./h after heating and holding for ３４34 hours, a tempering treatment was performed by furnace cooling at a rate of 15 ° C./h after heating and holding at 625-635 ° C. for 40-50 hours.

Nos. 13 and 14 are comparative steels which were heated at 900.degree.
After heating for 2 hours, quenching for cooling at a rate of 120 ° C./h was performed. Further, after heating and holding at 575 ° C. for 60 hours, tempering for cooling at a rate of 40 ° C./h was performed.

[0055]

[Table 1]

Table 2 shows the results of the tensile test, impact test, magnetic properties, and electrical properties. In the table, the magnetizing force is 20 kG
And at 21 kG. The values shown in the table are at 21 kG.

[0057]

[Table 2]

FIG. 2 is a diagram showing the effect of the Cr content on the tensile strength. As shown in the figure, the Ni content is 2.60-4.
At 15%, the tensile strength increases as the Cr content increases. In particular, when the amount of Cr exceeds 1.4%, the amount rapidly increases, and the effect of Cr is large. If it exceeds 2.0%, a high value of tensile strength of 100 kg / mm ² or more can be obtained.

FIG. 3 is a graph showing the relationship with the (Ni / Cr) ratio. As shown in the figure, the tensile strength decreases as the (Ni / Cr) ratio increases. In particular, (Ni / C
r) By setting the ratio to 2.1 or less, high strength can be obtained. There is also a relationship with the amount of Ni, and a high strength of 100 kg / mm ² or more can be obtained by setting a high Ni of 3.50% or more. For a target tensile strength of 93 kg / mm ² or more, the (Ni / Cr) ratio can be obtained by setting the Ni / Cr ratio to 2.3 or less and Ni to 3.5% or less. If the Ni content is less than 3%, it is difficult to obtain.

FIG. 4 also shows the relationship with the amount of Si. It can be seen that the strength is increased by increasing the amount of Si. If the Si content is 0.17% or more, 93 kg / mm ² or more can be obtained with 1.3 to 1.8% of Cr and 2.6 to 3.5% of Ni.
If the Cr content exceeds 2%, 93% or less of the low Si content is 0.1% or less.
kg / mm ² or more, especially 100 kg / mm ² or more.

FIG. 5 is a diagram showing the effect of the amount of Ni or Cr on the 50% fracture surface transition temperature. As shown in FIG.
Both Cr and Cr increase the content of FATT.
In particular, if the content of Cr is 0.5% or more when the content of low Si is 0.1% or less, a FATT of 0 ° C. or less can be obtained. In particular, if the amount of Si exceeds 0.1%, it is difficult to obtain a FATT of 0 ° C. or less even if Ni and Cr are increased.

FIG. 6 is a graph showing the effect of the amount of Si on FATT. As shown in the figure, lowering the amount of Si lowers FATT, thereby obtaining high toughness. In particular, in the vicinity of Ni 2.5 to 3.0% and Cr 1.3 to 1.8%, the Si content is 0.08% or less, Ni 3.5 to 4.0% and C
When r is in the vicinity of 1.5 to 2.2%, the temperature can be reduced to 0 ° C. or lower by setting it to 0.13% or lower. Cr over 2.2%, Ni over 3.5%, 0.20% or less at 0 ° C
It is possible to:

FIG. 7 is a graph showing the relationship between FATT and the amount of Al. Since the content of Al is also an element that enhances FATT, it is 0.014% or less in the vicinity of Cr 2.05 to 2.2% and Ni 3 to 4%, and Cr 2.2 to 2.5% and Ni 3.5 to 2.5%.
In the vicinity of 4.5%, the temperature can be reduced to 0.01 ° C. or less and 0 ° C. or less. When the amount of Ni is as high as 3.5% and the amount of Al is reduced near Cr 1.65%, it is difficult to obtain the temperature of 0 ° C. or less.

FIG. 8 shows the relationship between the magnetizing force and the amount of Si. As shown in the figure, an increase in the amount of Si increases the magnetizing force. In particular, Cr 1.5-2.5% and N
By setting the amount of Si to 0.18% or less around i2.5-4.5%, the magnetizing force at 21 kG can be made 900 AT / cm or less. In particular, when the amount of Si is 0.1% or less, a magnetizing force of 700 AT / cm or less can be obtained.

FIG. 9 also shows the magnetization force and P, S, Sn, S
It is a diagram showing the relationship between the total amount of b, As. These impurities are not preferable because they increase the magnetizing force.
In order to make it less than cm, it should be made less than 0.040%. In particular, in order to make it 700 AT / cm or less, 0.03% or less is preferable.

FIG. 10 shows the relationship between the magnetizing force and the amount of Al. As shown in the figure, Al is not preferable because it increases the magnetizing force. When the above-mentioned Cr, Ni content and Si content are 0.1% or less, the Al content should be 0.025% or less in order to obtain a magnetizing force of 990 AT / cm or less, and particularly 0.015% in order to make the magnetization force 700 A / cm or less. The following is preferred. For Si exceeding 0.1%, the amount of Al is preferably set to 0.01% or less.

FIG. 11 also shows the effect of a value obtained by multiplying Si and (the total amount of P, S, Sn, Sb, and As) on the magnetizing force. The higher the value, the worse the magnetizing force. If the value is 70 × 10 ^-4 or less, 990AT
/ Cm or less.

Example 2 Table 3 shows a tensile test, an impact test and a magnetic property test of a sample in which the steels Nos. 2 to 4 and 6 of the present invention were strengthened (the tempering temperature was lower by 5 ° C. than in Example 1). The results are shown.

As is clear from the table, the material of the present invention has a tensile strength of 105 kg / mm ² or more, a 0.02% proof stress of 82 kg / mm ² or more, a FATT of −44 ° C. or less, a magnetizing force of 400 AT / cm or less, and a 1200 MVA class. And 1300 MVA class generator sufficiently satisfy the mechanical and magnetic properties required for the rotor shaft material. Therefore, it can be said that the material of the present invention is extremely useful as a rotor shaft for a large-capacity generator of 1200 MVA or more.

[0070]

[Table 3] In this embodiment, an AC turbine generator driven by thermal power or nuclear power using the rotor shaft made of the material of Embodiments 1 and 2 is an example of a two- or four-pole cylindrical rotary field synchronous generator. It is.

Most of the turbine generators for thermal power are high speed machines having two poles, and have a rotation speed of 3,000 rpm, 6 at 50 Hz.
It becomes 3,600 rpm at 0 Hz. This is because the higher the speed, the more efficient and smaller the turbine. In most cases, tandem compound type that outputs power by one axis is used, but cross-compound type that outputs power by two axes is used in large capacity machines.

Nuclear turbine generators are usually 4 poles and 1,
Used at 500 rpm or 1,800 rpm. This is because the steam generated by the reactor is large, low temperature and low pressure compared to the thermal power, and the turbine has long blades and low rotation speed.

As a cooling system of the turbine generator, there are an indirect cooling system and a direct cooling system, and air, hydrogen and water are mainly used as a cooling medium.

[0074] Hydrogen cooling is used in a large capacity, and there are both indirect and direct types, all of which have an explosion-proof sealed structure in which a gas cooler is incorporated in the generator body. In the case of water cooling, a direct cooling system is used, and in a large-capacity machine, both a stator and a rotor may be a water cooling system.

FIG. 12 shows an example of a stator coil direct water-cooled turbine generator according to the present invention. (Stator) The stator frame is made of welded steel plate to form a ventilation path, and is made firmly to support the iron core and prevent vibration. The iron core is deformed into an elliptical shape by the magnetic attraction, and the vibration of the double frequency is generated with the rotation of the rotor.
Since this vibration increases as the size of the machine increases, an elastic support structure is used in which the iron core and the stator frame are attached via a spring.

The stator core 2 has 0.35 or 0.5 mm
A thick silicon steel sheet is used, and a directional silicon steel sheet is used. The iron core is laminated about 50-60mm in the axial direction,
An I-beam spacing piece is inserted so as to form a ventilation duct between them.

The stator winding 7 is usually a two-layer winding, but in the case of a two-pole machine, the winding ends are particularly long and must be firmly held. A non-magnetic material is used for the end structure because the stray load loss increases. (Rotor) A major feature of the turbine generator is that it rotates at high speed, and the centrifugal force increases, so that the rotor diameter is limited. A rotor 16 is integrally forged to secure mechanical strength to the rotor structural material and to avoid a critical speed and to suppress vibration. A slot 16 shown in FIG. 14 is machined, and a field winding is inserted therein. FIG. 13 shows the shape of the rotor 1.

The material of the main shaft is Ni-Cr-M according to the present invention.
It consists of oV steel. Although not shown in the drawing, a mounting ring 17 for the fan 20 is provided between the flange 15 and the centering 18.

The field winding 3 is formed by flat-winding a copper strip, and is distributed-wound in a rotor core slot formed between the teeth 12 to inject interlayer insulation every turn of the conductor. The end of the winding is held down by a retaining ring 9. Silver-containing copper having good creep characteristics is used for the coil instead of ordinary copper.

The retaining ring 9 is made of a non-magnetic stainless steel containing C 0.1% or less, N 0.4% or more, 10 to 25% Mn, and 15 to 20% Cr. After the winding 3 is embedded in the slot 16, it is fixed by fitting a wedge 13 made of a super duralumin alloy into the widest part of the slot 16. For the end damper ring 14, an end portion or a full-length damper is used, and an end Al alloy or a body silver-containing copper alloy is used. 8 is a shaft, 11 is a magnetic pole, and 15 is a coupling. (Ventilation system) A large-sized machine of 1000 MVA class or more and having a long iron core have difficulty in uniform cooling, so a double ventilation system is used.

In this system, several air supply chambers and exhaust chambers are alternately arranged in the axial direction in the stator frame behind the iron core, and the cooling air is supplied from both ends of the generator to the wind tunnel in the stator frame. After that, it is collected in each air supply chamber, cools the stator core from this, flows to the outer diameter side together with the gas cooled inside the rotor,
It circulates through the cooler to the intake side of the fan.

The gas pressure for hydrogen cooling was 2 at with an indirect hydrogen cooler.
g, 2 to 5 atg of direct hydrogen cooler is used. When the hydrogen gas pressure is increased, the heat transfer coefficient increases and the heat capacity of the gas increases in proportion to the density, so the temperature rise of the gas itself decreases in inverse proportion to the absolute pressure of the gas, increasing the cooling effect. I do. The output of a machine of the same size is generally 11 at 1 atg if the output at indirect cooling type 0.05 atg is 100.
125 outputs at 5.2 atg.

The hydrogen cooling system becomes explosive when the volume of hydrogen is 10 to 70% when mixed with air. To prevent this, the hydrogen purity is automatically maintained at about 90% or more. For this reason, a sealing device with an oil film is provided inside the bearing to prevent hydrogen gas inside the machine from leaking along the shaft to the outside of the machine. ing. Gas leakage from inside the machine is prevented by flowing oil at a higher pressure than the hydrogen gas inside the machine in the narrow gap of the shaft.

Even when the stator is indirectly cooled in the hydrogen-cooled turbine generator, the rotor is often directly cooled. (Direct cooling) When the maximum temperature of the conductor of the generator coil limits the output, the conductor is directly cooled by a cooling medium in order to eliminate the temperature difference in the insulator, which accounts for a large part of the temperature rise.

As a cooling medium, there is a liquid such as hydrogen gas or oil or water. Water has about 50 times the heat transfer capacity of air and is an excellent cooling medium.

(1) Direct cooling of hydrogen gas An example of a stator coil is shown, in which a conductor is directly cooled by passing gas into the inside of a square vent tube sandwiched between wires. Some of the heat generated by the conductor is transferred to the iron core through the main insulation having a large thermal resistance and is cooled, but most of the hydrogen gas is carried away through a cooling pipe having a small thermal resistance.

For liquid cooling, pure water having a large specific heat and a very high heat transfer coefficient by convection is used.

Stainless steel is used for the piping serving as the liquid passage, and oxygen-free copper or deoxidized copper is used for the coil and the clips at the ends of the coil. A Teflon (registered trademark) tube having high mechanical strength, high flexibility, and good insulation is usually used for the insulated connection tube. The cross section of the stator coil is such that the element wire is hollow, through which liquid flows.

(2) Hydrogen gas or water is used as a cooling medium for the rotor, and the following methods are available. In the end feed method, the hydrogen gas pushed into the rotor coil from the rotor end is discharged to the air gap through a hole formed in the center of the rotor. It is also preferable to use a system in which the coil enters the copper band from one end of the rotor and exits from the other end.

The cross-sectional shape of the rotor coil may be either a bypass type or a hollow copper band type. In this case, the stator coil is directly cooled by gas, and a high-pressure blower is attached to one end of the rotor.

In the air gap pickup system, suction and discharge holes are alternately provided on the rotor surface, and hydrogen gas in the air gap is sucked from the surface of the coil wedge using the wind speed due to rotation, and the coil copper band is used. There is a method in which the generated heat is deprived by flowing through the inside through a certain distance to exit through an exhaust hole to an air gap portion, or a method in which water is passed through a rotating body in a water cooling technique for a rotor.

The water cooling system is disadvantageous in terms of reliability because of its complicated structure as compared with the hydrogen gas cooling system.
The weight of the generator is reduced by about 15 to 25%, and the efficiency at a partial load can be improved.

In the figure, 15 is a flange connected to the turbine, 20 is a fan, 21 is a stator coil, 22 is a brush, and 23 is a slip ring.

FIG. 1 shows a turbine output of 1000 MW class (generator capacity of 1120 MVA class) using the material of the present invention.
It is a perspective view of the above-mentioned rotor shaft for large turbine generators. The rotor shaft according to the present invention was manufactured as follows.

About 15 compositions produced by vacuum ladle refining after melting in the air with the aim of substantially the same composition as No. 2 described in Example 1
0t of molten metal was cast in a mold. Next, hot forging was performed by a press, followed by upsetting (forging ratio 1/2 U) and then forging (forging ratio 3S). Furthermore, after performing homogenizing and sintering at 900 ° C. and cutting into a predetermined shape, the whole is cut at 840 ° C. for 2 hours.
After heating and holding in a vertical furnace for 0 hour, quenching was performed at a cooling rate of 100 ° C./h in the center hole by water spray. Next, a tempering treatment was performed in which the steel sheet was heated and held at 580 ° C. for 60 hours and then cooled at a rate of 15 ° C./h. Thereafter, cutting was performed on the final shape shown in FIG. This embodiment is for two poles, 11 is a magnetic pole, 12 is a tooth, 17 is a fan mounting ring, 18
Is the centering ring for mounting the retaining ring, 1
9 is a center hole. In this part, samples were taken to examine the mechanical, electrical, and magnetic properties of the material.
The centering ring 18 is integrated when the shaft is formed, but after being cut into a ring shape, the retaining ring is shrink-fitted.

In this embodiment, the total length is about 15 m and the teeth 12
The body diameter is 1.2m and the body length is about 7m
The body diameter is about 5.7 times. The machine size is about 10 m ³ of this compound, and thus reduce the vibration sensitivity of the rotor by, it is possible to suppress the phase imbalance sensitivity low, has high bearing stability decreased flexibility of the shaft Is obtained.

The machine size is represented by (rotor trunk outer diameter) ² × (rotor trunk length).

The relationship between the machine size of the rotor shaft and the generator capacity (MVA) in the present invention is expressed by the following equations (1) and (2).
Is preferably within the range.

Machine size (m ³ ) = 4.7 + 3.2 × 10 ⁻³ × Generator capacity (MVA) (1) Machine size (m ³ ) = 4.5 + 5.7 × 10 ⁻³ × Generator capacity (MVA) (2) The mechanical properties, magnetic properties, and electrical properties in this example were equivalent to those of the alloy No. 2 in Example 1.

The specifications in this embodiment are as follows.

Generator capacity: 1120 MVA, Stator current: 22 A per MVA of generator capacity, power factor: 0.9, rotation speed: 3600 rpm, frequency: 60 Hz, stator: direct water cooling, rotor: direct hydrogen cooling (generator 0.1 per MVA capacity.
0047 kg / cm ² · g), casing material: SM41 steel, iron core material: oriented silicon steel sheet, coil: electric copper, insulating material,
Epoxy resin and mica, body length / body diameter of coil embedded part = 5.83, retaining material: C0.1% or less, N
18% Mn-18% Cr not less than 0.7 and not more than 1% of Si
Steel, full length damper, rotor coil: silver-copper, bearing: carbon steel cast steel, overall dimensions: length 16m, width 6m, floor area 96
m ² .

With the above structure, 1000M
For a W-class turbine output, the generator capacity is 1120 MVA
And the floor area of the generator per MVA is 0.086.
m ^2, and the floor area per 1MVA generator of conventional 700MW class turbine (capacity 800MVA) 0.098m ²
The size can be reduced by about 13%. This floor area can be between 0.08 and 0.09 m ² per 1 MVA of generator capacity.

According to the low-alloy steel of the present invention, the upper and lower limits of the body diameter are determined from the above machine size values, and the upper limit diameter D (mm) is determined by the following equation (3). It is preferable that the value to be obtained and the lower limit diameter are values obtained by Expression 4. The torso length is 5.5 of its diameter
~ 6.5 times is preferred.

Body diameter D (mm) = 0.2 × Generator capacity (MVA) +1000 (3) Body diameter D (mm) = 0.2 × Generator capacity (MVA) +900 (4) With this structure, the vibration sensitivity of the rotor is small, and the entire generator can be made compact.

[0105]

According to the present invention, the room temperature tensile strength is 93 kg /
mm ² or more, 50% fracture appearance transition temperature 0 ℃ below magnetizing force at 21kG is obtained has the following characteristics 990AT / cm, generator capacity 900MVA more mass generator or rotation number 5
A synchronous motor of 000 rpm or more can be manufactured compactly. As a result, the installation area can be effectively used, and particularly in power generation, it can contribute to diversification of energy of oil, coal, and nuclear power.

[Brief description of the drawings]

FIG. 1 is a perspective view of a rotor shaft for a rotating electric machine according to the present invention.

FIG. 2 is a diagram showing a relationship between tensile strength and Cr.

FIG. 3 is a diagram showing a relationship between tensile strength and (Ni / Cr) ratio.

FIG. 4 is a diagram showing a relationship between tensile strength and Si.

FIG. 5 is a diagram showing a relationship between FATT and Ni or Cr.

FIG. 6 is a diagram showing a relationship between FATT and Si.

FIG. 7 is a diagram showing a relationship between FATT and Al.

FIG. 8 is a diagram showing a relationship between a magnetizing force and Si.

FIG. 9 is a diagram showing a relationship between a magnetizing force and P + S + Sn + Sb + As.

FIG. 10 is a diagram showing a relationship between a magnetizing force and Al.

FIG. 11 shows magnetization force and Si × (P + S + Sn + Sb + A).
The figure which shows the relationship with s).

FIG. 12 is a sectional view of a turbine generator.

FIG. 13 is a perspective view of a rotor for a turbine generator.

FIG. 14 is a sectional view of a slot of a rotor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... Stator, 3 ... Field winding, 4 ... Bearing bracket, 5 ... Stator frame, 6 ... Bearing, 8 ... Shaft, 9 ... Retaining ring, 10 ... Cross slot, 11 ... Magnetic pole, 12: teeth, 13: wedge, 1
4 ... End tampering, 15 ... Coupling, 16 ...
Slot, 17: Fan mounting ring, 18: Centering ring, 19: Center hole, 20: Fan, 21: Stator coil, 22: Brush (graphite), 23: Slip ring.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 19/22 H02K 19/22 (72) Inventor Yoshinobu Mori 4026 Kuji-cho, Hitachi City, Ibaraki Pref. Hiroshi Fukui, Inventor Hiroshi Fukui 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Tatsuro Ishizuka 3-1-1 Sachimachi, Hitachi City, Ibaraki Co., Ltd. Inside the Hitachi Works of Hitachi, Ltd.

Claims (17)

[Claims] (1) By weight, C 0.15 to 0.30%, Si 0.
1% or less, Mn 0.05-1%, Ni 3.0-5.0%,
Cr 2.05 to 3.0%, Mo 0.1 to 1.0%, V0.0
A rotor shaft for a rotating electric machine, wherein 3 to 0.35% and the balance are substantially Fe. 2. 0.15% to 0.35% by weight of C.O.
1% or less, Mn 0.05-1%, Ni 3.25-5.0
%, Cr 1.5 to 3.5%, Mo 0.1 to 1.0%, V0.
A rotor shaft for a rotating electric machine, characterized in that the ratio (Ni / Cr) is from 1.2 to 2.3, and the balance is substantially 0.3 to 0.35% and the balance is substantially Fe. 3. The composition according to claim 1, wherein C is 0.15 to 0.30% by weight and Si is 0.1%.
3% or less, Mn 0.05-1%, Ni 3.0-5.0%,
Cr 2.05 to 3.0%, Mo 0.1 to 1.0%, V0.0
3 to 0.35%, A10.006% or less, and the balance is substantially Fe. 4. The composition according to claim 1, wherein C is 0.15 to 0.30% by weight and Si is 0.1%.
2% or less, Mn 0.05-1%, Ni 3.0-5.0%,
Cr 2.05 to 3.0%, Mo 0.1 to 1.0%, V0.0
3 to 0.35%, with the balance being substantially Fe, having a tensile strength at room temperature of 93 kg / mm ² or more, a 50% fracture surface transition temperature of 0 ° C. or less, and a tempered bainite structure. Rotor shaft for electric machines. 5. The method according to claim 5, wherein C is 0.15 to 0.30% by weight and Si is 0.1%.
1% or less, Mn 0.05-1%, Ni 3.0-5.0%,
Cr 2.05 to 3.0%, Mo 0.1 to 1.0%, V0.0
3 to 0.35%, 0.001 to 0.1% of at least one element of the group IIa element and the group IIIa element, and the balance substantially F
e. A rotor shaft for a rotating electric machine, wherein 6. 0.15% to 0.30% by weight of Si, 0.3% by weight.
1% or less, Mn 0.05-1%, Ni 3.0-5.0%,
Cr 2.05 to 3.0%, Mo 0.1 to 1.0%, V0.0
3 to 0.35% and the balance substantially Fe, 21 kG
Characterized by having a magnetic susceptibility of 990 AT / cm or less and a tempered bainite structure. 7. 0.15% to 0.30% by weight of C.O.
1% or less, Mn 0.05-1%, Ni 3.0-5.0%,
Cr 2.05 to 3.0%, Mo 0.1 to 1.0%, V0.0
A rotor shaft for a rotating electric machine, characterized in that 3 to 0.35%, at least one element of group IVa element, Nb, Ta and W is 0.2% or less and the balance is substantially Fe. 8. The composition according to claim 1, wherein C is 0.15 to 0.30% by weight and Si is 0.1%.
1-0.3%, Mn 0.05-0.5%, Ni 3.25-
4.5%, Cr 2.05 to 2.60%, Mo 0.25 to 0.2
A rotor shaft for a rotating electric machine, characterized in that the rotor shaft is 60%, V 0.05 to 0.20%, Al 0.01% or less, and the balance is substantially Fe, and has a tempered bainite structure. 9. 0.15% to 0.30% by weight of C.O.
3% or less, Mn 0.05-0.5%, Ni 3.0-5.0
%, Cr 1.5 to 3.5%, Mo 0.1 to 1.0%, V0.
03-0.35%, Al 0.01% or less, P, S, Sn, S
b and As total amount of not more than 0.03%, (Ni / Cr)
A rotor shaft for a rotating electric machine, comprising a low alloy steel having a ratio of 1.2 to 2.3. 10. The composition according to claim 1, wherein C is 0.15 to 0.30% by weight,
0.01 to 0.30%, Mn 0.05 to 0.5%, Ni 3.0
5.0%, Cr 2.05 to 3.5%, Mo 0.1 to 1.0%
%, V 0.03 to 0.35%, Al 0.0005 to 0.006
%, The total amount of P, S, Sn, Sb and As is 0.001 to 0.00.
025%, with the balance substantially consisting of Fe. 11. A rotor shaft for a rotating electrical machine having a body having an axial slot into which a coil is embedded, a flange for transmitting and receiving power, and a bearing, wherein the shaft has a tensile strength at room temperature of 100 kg / mm. ² or more, 50% fracture surface transition temperature -44 ° C or less and magnetizing force at 21 kG is 500
A rotor shaft for a rotating electrical machine, comprising the rotor shaft for a rotating electrical machine according to any one of claims 1 to 10 having an AT / cm or less. 12. A rotor shaft for a rotating electric machine according to claim 11, wherein said shaft has a body diameter of 1 m or more and a body length of 5.5 to 6.5 times the body diameter. . 13. The shaft according to claim 11, wherein the value of (D ² × R ² ) obtained from the relationship between the body diameter D (mm) and the rotational speed R (rpm) is 1.0 to 1.0. A rotor shaft for a rotating electric machine, wherein the body diameter is set with respect to the number of revolutions so as to be 3.0 × 10 ⁷ . 14. The body diameter D (mm) according to claim 11 or 12, wherein the diameter D (mm) is reduced to 0.2 mm per 1 MVA of the generator capacity.
A rotor shaft for a rotating electric machine, wherein the rotor shaft has a value equal to or less than a value obtained by adding 00 mm and a value obtained by adding 900 mm to 0.2 mm per 1 MVA of the generator capacity. 15. A large-capacity rotating electric machine having a stator having a laminated core having a coil embedded therein, a rotor rotating within the stator and having a conductor coil embedded therein, and having a capacity of 900 MVA or more, 15. The rotating electric machine according to claim 1, wherein the rotor has a tensile strength at room temperature of 100 kg / mm ² or more, a 50% fracture surface transition temperature of −44 ° C. or less, and a magnetizing force at 21 kG of 500 AT / cm. It is constituted by a rotor shaft, the shaft body diameter is 1.15 m or more, the body length is 5.5 to 6.5 times the body diameter, and receives a rotation of 3000 rpm or 3600 rpm. Capacity rotating electric machine. 16. A generator capacity of 900 MVA or more, a stator current of 19 to 24 A per 1 MVA of the rotating electric machine capacity, the stator being directly water-cooled, and a rotor of 0.000 per 1 MVA capacity.
Cooled at a hydrogen pressure of 3 to 0.006 kg / cm ² · g,
The rotor has a room temperature tensile strength of 100 kg / mm ² or more, 50
The rotor shaft for a rotating electric machine according to any one of claims 1 to 14, wherein the magnetizing force at a% fracture surface transition temperature of -44 ° C or lower and 21 kG is 500 AT / cm or lower, and the body diameter of the shaft is 1. A large-capacity rotating electric machine having a length of 0 m or more. 17. A generator having a rated capacity of 1,120,000 KVA.
And the stator and the inside of the stator are rotated and the conductor coil is embedded.
A generator comprising a rotor, wherein the stator is
The rotor is water-cooled, and the rotor is cooled with hydrogen gas.
Is the tensile strength at room temperature 100kg / mm ^Two Above, 50% fracture surface transition
Magnetization force of 500 A at temperatures below -44 ° C and 21 kG
The cycle according to any one of claims 1 to 14, wherein the cycle is not more than T / cm.
A rotor shaft for a rotary electric machine;
The body diameter of 1.15 to 1.35 m and ((body diameter)^Two×
(Body length)) required machine size is 9 ~
10m^ThreeThe rotor receives 3600 rpm rotation.
And a large capacity generator.