S. Kikuchi

Microfabrication and characteristics of magnetic thin-film inductors in the ultrahigh frequency region

Thin-film inductors for 1 GHz-drive mobile communication handset application has been demonstrated. This is the possible practical application of soft magnetic films in 1 GHz range. Fe61Al13O26 with Ms=1.2 T, ρ=500 μΩ cm, fr=2 GHz were used for the inductors. L=7.6 nH, R=6.5 Ω, and Q=7.4 were obtained at 1 GHz in a 370 μm×370 μm square four turn spiral of line/space=11 μm/11 μm covered with 0.1-μm-thick slitted Fe61Al13O26 film with Cr underlayer. The L was increased over the flux saturated inductor by 8.6% without any degrade of quality factor.

Design and characteristics of a new magnetic worm gear using permanent magnet

The structure and the method of design of a magnetic worm gear using a permanent magnet are described. The basic concept of the design is as follows: high gear ratio; and meshing based on internal contact to enlarge the meshing area and reduce the size of the gear. The trial magnetic worm gear has a gear ratio of 1:33. The measured maximum transmitted torque is 11.5 Nm. >

Consideration of contactless power station with selective excitation to moving robot

A new method of contactless energy transmission to a moving machine is proposed. This system is useful for application with moving robots, including electric vehicles such as an electric wheelchair, an automatic guided vehicle, and so on. A moving robot was used as a model experimental system with these loads. The primary coils, an arrangement of spiral coils used with the selective excitation system, are located on the floor. A secondary spiral coil is attached to the bottom of the robot. The robot receives the magnetic flux radiating from the primary coils, which serves as the power source for the robot. In terms of electric power, in this experimental system the robot needs at least 2 W to start moving. As the robot moves, the excitation follows its movement. We have studied the characteristics of power transmission when the robot moves from one primary coil to another. This selective excitation system was found to be very effective for the overall efficiency of electric power transmission. We also examined the efficiency of the coil system used herein. Based on a comparison of the closed magnetic loop circuit and the open magnetic loop circuit, the efficiency of the former determined to be 70 [%] and that of the latter was determined to be 9 [%]. A monitoring system was constructed to ascertain which coil was excited. Based on our results, it would be possible to apply this contactless power transmission system to larger systems.

A new meander type contactless power transmission system-active excitation with a characteristics of coil shape

We propose a contactless power transmission system using a new meander type coil. Effectiveness for stabilizing the amount of the transmitted power against a load displacement and suppressing electromagnetic noise emission is the features of meander type coils. Maximum power is transmitted when the pitch of the transmitter coil corresponds to the receiver shape. An Active Excitation System was realized using circuit in which the relative position between transmitter and receiver coils are always assured. Furthermore the system result is an optimal distribution of flux. Therefore, the receiver position is cleared and transmitter-pitch is set up optimally.

Trial construction of a new magnetic skew gear using permanent magnet

This paper describes the structure and the design method of a magnetic skew gear using a permanent magnets. The magnetic skew gear can be easily designed by expansion of the design method for a magnetic worm gears. The trial magnetic skew gear has a gear ratio of 1=38/66=0.575 and has an internal contact meshing to increase the transmitted torque by enlarging the meshing area. >

Local hyperthermia based on soft heating method utilizing temperature-sensitive ferrite rod

A description is given of soft heating, an induction heating method which uses an implantable heater consisting of temperature-sensitive magnetic materials and a metal ring. Local hyperthermia based on soft heating is experimentally shown to be effective. A phantom test reveals that a piece of heater supplies sufficient heat to surrounding tissues whose volume is 1 cm/sup 3/. Wister rats and Walker Carcinosarcoma 256 were used in an animal experiment. Tumors in five rats vanished almost completely after four heating treatments. The accuracy of the regulation is +or-0.2 degrees C near the Curie temperature, which can be readily varied. >

Characteristics of a new AC motor making good use of parametric oscillation

This paper is a description of the operating principle and the construction of a new AC motor making good use of parametric oscillation. This motor is constructed by two magnetic cores of U-shape, a stator of ring form, a cage rotor of usual induction motor and two windings. It has a number of excellent operating characteristics.

Some considerations on the anomalous phenomenon of parametric induction motor

The stability of the parametric induction motor is analyzed in this paper. In results, the anomalous phenomena observed in operation is clarified and the method to avoid the undesirable phenomena is obtained. The results of this study will be useful for designing stable parametric induction motors.

Performance of soft heating for local hyperthermia using temperature sensitive amorphous metal flakes

A heater made of temperature-sensitive amorphous metal flakes with a length of 100 approximately 800 mu m is proposed. The calorific power of the heaters is calculated, making some simplifying assumptions. The analysis shows the conditions that must be satisfied when the amorphous flakes are used for heating. A balloon filled with the flakes can be used, or the shape of the heater can be tailored to suit the form of the malignant tumor to be heated. No temperature monitoring is needed. >

Characteristics of a parametric synchronous motor and a parametric induction generator made for test

This paper describes the structure and the operation of two new machines using rotational field based on a parametric oscillation. One of the machines is the parametric synchronous motor using permanent magnet rotor. Another one is the parametric induction generator. These machines have a number of interesting features in construction and operation. The results of this study seem to be useful for development of electrical machines and to introduce a new field for application of the parametric machine in the future.