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Yamazaki K.,Chiba Institute of Technology | Suzuki A.,Toyo Electrical Manufacturing Co. | Ohto M.,Yaskawa Electric Co. | Takakura T.,Yaskawa Electric Co.
IEEE Transactions on Industry Applications | Year: 2012

In this paper, we investigate the harmonic losses and torque of high-speed induction motors from both results of measurements and calculations. The calculation method of harmonic core losses and torque has been developed from the viewpoint of practical and useful application to rotating machines. This method is based on the combination of 2-D and 1-D finite-element methods with approximated core loss modeling, which requires only few material constants obtained by Epstein frame tests. The frequency and the flux density dependence of the core loss are modeled by the 1-D analysis along the thickness direction of electrical steel sheets. Furthermore, the proposed method can decompose the total loss and torque into harmonic components because of its simple modeling. This decomposition reveals the main loss factors and the decrease in the torque of the high-speed induction motors due to the harmonic core losses. The validity of the calculation is confirmed by measurements. In addition, useful information for the design of high-speed induction motors is obtained by using the proposed method. © 2012 IEEE. Source

Yamazaki K.,Chiba Institute of Technology | Suzuki A.,Chiba Institute of Technology | Suzuki A.,Toyo Electrical Manufacturing Co. | Ohto M.,Yaskawa Electric Co. | Takakura T.,Yaskawa Electric Co.
IEEE Transactions on Energy Conversion | Year: 2013

The circuit parameters involving stray load loss and harmonic torques of high-speed induction motors fed by inverters are determined by both finite-element method and experiments, respectively. In the finite-element method, the parameters are directly determined from the electromagnetic field distribution of the motors under load conditions. On the other hand, in the experiment, the parameters are determined from no-load, locked rotor, and load tests. The characteristics calculated by the proposed circuits are compared with those of the measurement in order to confirm the validity and usefulness of the proposed circuit. It is clarified that the accuracy of the calculated characteristics is significantly improved by the proposed circuit as compared to the conventional circuit, particularly under high-speed conditions. © 1986-2012 IEEE. Source

Sasaki T.,Kanazawa University | Maruyama Y.,Kanazawa University | Ohba H.,Toyo Electrical Manufacturing Co. | Ejiri S.,Iwate Medical University
Journal of Instrumentation | Year: 2014

In this study, an application of the two-dimensional imaging technology to the X ray tri-axial stress analysis was studied. An image plate (IP) was used to obtain a Debye-Scherre ring and the image data was analized for determining stress. A new principle for stress analysis which is suitable to two-dimensional imaging data was used. For the verification of this two-dimensional imaging type X-ray stress measurement method, an experiment was conducted using a ferritic steel sample which was processed with a surface grinder. Tri-axial stress analysis was conducted to evaluate the sample. The conventional method for X-ray tri-axial stress analysis proposed by Dölle and Hauk was used to evaluate residual stress in order to compare with the present method. As a result, it was confirmed that a sufficiently highly precise and high-speed stress measurement was enabled with the two-dimensional imaging technology compared with the conventional method. © 2014 IOP Publishing Ltd and Sissa Medialab srl. Source

TOYO Electrical Manufacturing CO. and A&D Company | Date: 2011-09-13

A chassis dynamometer for a vehicle has a base seat, a fixed shaft having one end thereof attached to the base seat, a rotary proximal portion rotatably supported to the fixed shaft, a roller connected to the rotary proximal portion, for loading a wheel of a vehicle, and a motor connected to the roller so that power can be transmitted therebetween. The roller has a single flange portion connected to the rotary proximal portion and extending obliquely to the axis, and an outer peripheral portion extending both axial directions from an outer periphery of the flange portion and disposed outward in the radial direction of the motor.

Toyo Electrical Manufacturing Co. | Date: 2011-11-09

Main circuit of an electric power generating apparatus for dispersed power supply, having a permanent magnet type electric power generator driven by windmill or waterwheel and having three windings, each inducing a different value of induced voltage, AC outputs of the generator rectified by rectifiers, and DC outputs of the rectifiers summed in parallel for output. First and second reactors are respectively connected in series between first and second rectifiers and output terminals of first and second windings, the first winding inducing the lowest induced voltage among the three windings, the second winding inducing the second lowest. A capacitor is connected between a third rectifier and an output terminal of a third winding inducing the highest induced voltage. The sum of inductive impedance by internal inductance of the third winding and capacitive impedance by the capacitor is capacitive impedance within a range of rotational speed of the generator.

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