This explanation paper discusses acoustic and magnetic noise generated by an IH cooker. IH cooking heater is a cooker that applies the electromagnetic induction. Recently, influence of the electromagnetic wave on the human body is worried. The symptoms; user of home electronics appliances feels; are headache and nausea. There is a report that some users who are using IH cooking heater also feel these symptoms. We have discovered that the high frequency acoustic noise (ultrasonic range), which is generated from an IH cooker, indicates strong-level sound pressure. High frequency strong acoustic noise must not be ignored, because its danger on our health is reported scientifically and medical standpoints. And, due to the spread of power electronics device, noise superimposed on the AC power supply is a problem. It has been reported that the acoustic noise (Audible range) provides discomfort feeling when using the IH cooker.
Banko ware is famous for heat resistant ceramic wares such as earthen pot, ceramic plate and so on. Petalite is used as a raw material for these ceramic wares aiming for the enhancement of heat resistant property. Their thermal expansion coefficient is as low as 2.0×10-6 K-1 due to β-spodumen produced from petalite during firing in the body. Heat resistant property is also improved because the porous body is suppressed the spreading for cracks. In addition, the infrared radiation of them is much higher than that of metal wares, which made it possible to heat ingredients efficiently. It is expected that Banko ware with heat resistant and high infrared radiation properties, which are advantages for a kitchenware, is used continuously at the kitchen in the future.
The outline of the transition of the kitchen from ancient times to modern times was reported. The stainless steel sink born in the Japanese high-growth period has changed to the system kitchen equipped with various built-in multi-functional components. Materials for kitchen sink has changed from concretes, zinc, and iron at 1970s , to stainless steel during at the high growth period, and to resin nowadays. The fundamental way of thinking on the human and the earth conscious manufacturing was discussed with the transition of kitchen.
This paper deals with the quenching problem of electromagnetic vibration of the motor stator in the wide frequency region around the natural frequency. The iron stator is modeled by a perfect circular ring. To quench its vibration, single mass is set on the stator, it is supported by the two springs, and a pair of dynamic absorbers is installed on the outside of it. The solutions of forced vibration are obtained by the theoretical analysis and the finite element method. Following was made clear: (1) The vibration quenching effect is improved by using an imperfect mass and spring supports in addition to the dynamic absorbers. (2) If an imperfect mass is set to be effective for cos mode and spring supports are set to be effective for sin mode, and a pair of dynamic absorbers is installed about the angle between the loop and the node of the quenching target mode, higher quenching effect is obtained. (3) The results obtained by the theoretical analysis and the finite element method coincide qualitatively with each other.