No abstract

In designing a thermal overload relay, it is necessary to analyze thermal characteristics of several trial models. UP to now, this has been done by measuring the temperatures on a number of posi~ons in the trial models. This experimental method is undoubtedly expensive. In this paper, the temperature distribution of a thermal overload relay is obtained by using 3-D finite element analysis taking into account the current distribution in current-carrying conductors. It is shown that our 3-D analysis is capable of evaluating a new design of thermal overload relays.A new design of thermal overload relays requires analyzing thermal characteristics of several trial models. We propose a numerical method by which the temperature distribution of a trial model carrying current can be obtained instead of the experimental method in use today. II . ANALYSIS METHOD A. Analysis of Current DistributionIndex terms-Heat analysis, overload relays, finite element method.

Addition of excess antishudder additive to transmission oil results in a decrease of the friction coefficient to a level below which the transmission torque capacity becomes unsatisfactory. However, very low concentrations of antishudder additive can result in unsatisfactory antishudder performance and durability. To obtain the optimal balance between antishudder performance and torque capacity, a specific alkenylsuccinimide has been developed. The relationship between the antishudder performance and torque capacity was investigated by performing a series of low-velocity friction apparatus (LVFA) rig tests as well as statistical analysis using the quantitative structure-property relationship (QSPR) method that related the structure and physical properties of the molecule to the measured frictional properties.

The reduction in viscosity of Automatic Transmission Fluids (ATFs) for improving fuel economy results in a reduction in transmission gear fatigue life due to occurring pitting. The aim of this study is to establish a suitable test condition for evaluating differentiation in the gear pitting life between ATFs by using a Forschungsstelle fur Zahnrader und Getriebebau (FZG). In this study FZG gear sets were modified so that gear teeth were misaligned and the contact tooth width was shortened by offset in the direction of the shaft. The fatigue pitting life in response to ATFs under this modified FZG test condition was of the same order as that obtained in the actual transmission test under a severely offset condition. A sulfur-containing additive could play a role on the gear tooth life under severe condition, which was most likely attributed to tribofilm for motion on the gear tooth surface.