IEEJ Transactions on Industry Applications
Online ISSN : 1348-8163
Print ISSN : 0913-6339
ISSN-L : 0913-6339
Volume 110, Issue 8
Displaying 1-10 of 10 articles from this issue
  • Masao Nakagawa
    1990 Volume 110 Issue 8 Pages 859-865
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
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  • Riichi Murayama, Kazuo Fujisawa, Sadao Yonehara
    1990 Volume 110 Issue 8 Pages 866-872
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    Compressive hoop residual stress in the rim of a new wheel prevents cracks from emerging on the wheel. But heat impacts in the course of braking operations decrease compressive hoop residual stress in the rim and develop tension hoop stress. As the result, cracks in the rim are growing and lead the wheel to failure. So the development of a nondestructive measurement tool of residual stress and its practical use for the maintenance field of railroad wheel are highly expected to prevent a wheel failure. From this view point we developed the instrument with EMAT for measurement of residual stress of railroad wheel using acoustoelastic effect.
    At first, this paper describes the principle of acoustoelastic effect and EMAT, after that, explain about the content of this instrument. Finally, we will discuss about the experimental result using this instrument.
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  • Takahiro Ara, Shoichi Oda
    1990 Volume 110 Issue 8 Pages 873-881
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    It is almost impossible to measure the starting performance of middle and large synchronous motors in a factory, because it needs a large capacity of equipments to test its performance.
    A new method is required to predict this performance by simple tests using a small capacity. This will make the motor's design and its accessories more rationalized.
    Authors propose a new method which is the combination of single phase AC applied test and usual routine test of synchronous machines.
    The key points of this method are summarized as follows:
    (1) The armature winding leakage reactance is resulted from the no-load saturation curve, the short-circuit characteristic curve and the armature-reaction magnetomotive force converted to the field current (design value).
    (2) A single phase voltage with commercial frequency is applied to armature terminals in a standstill condition. And this test must be performed twice, one for short-circuiting the field winding, the other for joining a resistance between the field terminals. Using these two test data including input power, the field and the damper winding impedances are separated from each other.
    The starting performance of a synchronous motor is predicted and agreed with actual data.
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  • Yoshitomo Okada, Sakae Shinomiya, Kouji Obayashi, Kimio Yamashita
    1990 Volume 110 Issue 8 Pages 882-890
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    In this paper, based on the performance equations, expressed by using the equivalent circuit, parameter ratios of a two-phase servomotor, the various performance characteristics [(1) the speed-average torque characteristics, (2) the influence of the alternating torque on the average torque, (3) the efficiency of servomotor, etc.], which have no connection with the output power of the two-phase servomotor, are investigated from the more general viewpoint, and these various performance characteristics are clarified.
    Secondly, based on the above investigated results, a guide for the design of the two-phase servomotor which has desirable performance characteristics [(1) the speed-average torque characteristics have the drooping ones, (2) the influence of the alternating torque on the average torque is small, (3) the efficiency of servomotor is high, (4) no single-phase operation, etc.], is presented in terms of the best parameter ratios.
    That is, if the various parameter ratios of the two-phase servomotor are designed to satisfy x1/xm=0.05, r1/xm=0.3, x2/xm=0.04 and r2/xm=0.40 respectively, it is clarified that the two-phase servomotor which has the desirable performance characteristics is obtained.
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  • Fuminori Ishibashi, Kazuo Kobayashi
    1990 Volume 110 Issue 8 Pages 891-898
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    The small squirrel cage three-phase induction motors have been used in all fields of industries for many years. Recently, further detailed studies about magnetic noise and stray load losses have been urged in relation to noise reduction and energy saving.
    Searchcoil voltage on stator and rotor were analyzed for frequency and harmonic flux orders, and its derivation were experimentally clarified. As a result, it was confirmed that time and space saturation harmonic flux had a different order and rotor mmf. included harmonic fluxes caused by stator harmonic fluxes.
    From experimental comprehensive analysis of harmonic magnetic fluxes, it was found that it was enough for harmonic flux to consider up to order 5.
    Experimental formulas were also confirmed to evaluate magnetic flux in the airgap due to stator mmf., permeance of airgap and slots, and iron core, considering saturation of iron (time and space separately). The formulas of magnetic flux due to rotor mmf. induced by current which depends on stator mmf. were similarly derived.
    The frequencies and magnitude of magnetic fluxes such as time, space and saturation (time and space) harmonic fluxes calculated by these formulas were examined with experimental results.
    As a result, most frequencies of magnetic fluxes of induction motor could be predetermined with these formulas.
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  • Mutsuo Tadokoro, Fujio Tatsuta, Hiromichi Nagata, Toshiaki Yamazaki
    1990 Volume 110 Issue 8 Pages 899-907
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    In a three-phase nonlinear circuit composed of nonlinear reactors and capacitors, there are two noteworthy phenomena. One is the voltage jump phenomenon, which is very useful, and has already been used in the field of power devices such as frequency triplers. The other is abnormal voltage oscillation, which is very harmful to stable operation. In this paper, the mechanism and regions of occurrence of these abnormal oscillations are analyzed in detail.
    It has been reported that voltage jumps in the three-phase nonlinear circuit can be analyzed by using only the zero-phase-sequence circuit equation. But positive- and negative-phase-sequence circuit equations are indispensable for analyzing abnormal oscillations. According to this analysis, it is shown that the resistances in the positive- and negative-phase-sequence circuits play the main role in these abnormal oscillations. It is also shown that there are two regions where the abnormal oscillations occur: the pre-jump region and post-jump region, and the fact that the former region occurs in the reactors' almost linear operating mode is particularly noteworthy.
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  • Isao Hirotsuka, Kazuo Tsuboi, Sadaaki Mori, Kunihiro Kato
    1990 Volume 110 Issue 8 Pages 908-916
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    Although electromagnetic vibration and noise of a squirrel-cage induction motor have been studied for a long time, many unclear factors for a capacitor induction motor used most widely under the single phase power source are still remained.
    This paper clarifies the radial electromagnetic vibration of the capacitor induction motor running at no load from the experimental results. Also taking account of the effects of magnetic saturation and natural frequencies of the test motor, the following matters are described;
    (1) Derivation of the general equation of electromagnetic force waves, considering not only forward magnetic field but also backward magnetic field, and its experimental verification,
    (2) Features of producing the dominant electromagnetic vibration of the capacitor induction motor for the number of poles and the slot combination,
    (3) Difference between the features of the three-phase squirrel-cage induction motor and the capacitor induction motor,
    (4) Effect of skewed slot on the dominant electromagnetic vibration.
    We hope that this paper will be a basis for the solution of electromagnetic vibration and noise of the capacitor induction motor.
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  • Takeshi Mizuno, Toshiro Higuchi
    1990 Volume 110 Issue 8 Pages 917-924
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    An unbalance on a rotor causes whirling motions of the rotor and alternating forces of the bearings in rotating machines. The authors have shown a magnetic bearing control system in which an unbalanced rotor can be suspended without whirling. The concept of designing the control system was that the effects of unbalance were estimated by an observer and cancelled by the electromagnetic forces of the bearing. With the control method applied, the position of the rotor can be maintained at the desired position with high precision. It is suitable for some machines, however, to minimize the variation of exciting currents or vibratory force transmitted to the base through the bearing. In this paper, control methods are presented which can eliminate stationary alternating components from exciting currents or electromagnetic forces by using the output of the observer. Another control method is presented which feedback the estimated signals of the displacements of the principal axis; such signals are obtained by compensating synchronous obsevatory disturbances by use of the output of the observer. It is shown that the proposed three control methods are equivalent when unbalance stiffness due to the bias magnetic flux is null.
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  • Masaaki Sakui, Hiroshi Fujita
    1990 Volume 110 Issue 8 Pages 925-926
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
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  • Takehisa Igari
    1990 Volume 110 Issue 8 Pages 927-928
    Published: August 20, 1990
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    Download PDF (831K)
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