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Technical Paper

Electromagnetic Characteristic Comparison of Superconducting Synchronous Motors for Electric Aircraft Propulsion Systems

Aircraft service has been increasing today and it also results in the increase of the greenhouse gas emission. To solve this problem, the electric aircraft propulsion system is the key solutions to realize the clean and high efficiency aircraft, while demanding higher output density motors. So far, though 5 kW/kg is realized with permanent magnet type synchronous motors, the electric aircraft for over 100 passengers demands motors with 16 -20 kW/kg. Superconducting (S.C.) technology is one of the effective candidates for higher output density motors. In comparison with copper wires, the S.C. wires have higher current density at less than –200 ℃. And we can make a lighter weight coil with the S.C. wires. So far, many groups have been studying the S.C. motors over 16 kW/kg. Generally, there are two kinds of S.C motors. One is the S.C. motors made of the S.C. field coils and copper armature windings. The other is the fully S.C. motors using S.C. field and armature windings.

Bolts and Screws, Roll Threaded Procurement Specification For


This procurement specification covers bolts and screws made from carbon steels, high expansion steels, or corrosion and heat resistant steels of the type identified under the Unified Numbering System as follows: a. UNS K00802 - carbon steel (AMS 5061) b. UNS K91505 - high expansion steel (AMS 5624) c. UNS K91456 - high expansion steel (AMS 5625) d. UNS S32100 - corrosion and heat resistant steel (AMS 5645) e. UNS S34700 - corrosion and heat resistant steel (AMS 5646)


Inspection of Ground, Chromium, Plated Steel Parts

This specification covers the requirements for inspection of ground chromium plated surfaces for grinder-induced damage to the chromium plate and substructure. The specification also provides users with criteria for distinguishing between such damage and acceptable indications inherent to the chromium plate.
Technical Paper

Structural Vibration and Acoustic Analysis of a 3-Phase AC Induction Motor

This paper aims to study the NVH and acoustic performance of a 3-phase AC induction motor in order to develop an approach to reduce the magnetic component of noise from an electric motor in an electric vehicle (EV). The final goal of this project is to reduce the magnetic component of sound from the motor by making modifications to the end bracket of the motor housing. EVs are being considered the future of mobility mainly due to the fact that they are environment-friendly. As many companies are already investing in this technology, electric drives are set to become extremely popular in the years to come. The heart of an EV is its motor. Modern electric vehicles are quiet, furthermore with the lack of an IC engine to mask most sounds from other components, the sound from the electric motor and other auxiliary parts become more prominent.
Technical Paper

A Novel Kind of Proportional Electromagnetic Dynamic Vibration Absorber

A new proportional electromagnetic dynamic vibration absorber (EDVA) is proposed for control of engine vibration during idling. The device consists of an electromagnetic actuator attached to the primary structure through elastic element, where the driving force pair is implemented between the reaction-mass and the primary structure. The design of the proportional electromagnetic actuator is realized considering the geometric parameters of the core to achieve nearly constant magnetic force over a broad range of its dynamic displacement but proportional to square of the current. A methodology is proposed to achieve magnetic force proportional to square of current and consistent with the disturbance frequency. The proportional EDVA is subsequently applied to a single-degree-of-freedom primary system with an acceleration feedback control algorithm for attenuation of primary system vibration in a frequency band around the typical idling vibration frequencies.

Fasteners - Part Standard - Cap Screws, Hex Bolts, and Hex Nuts (Metric)

This SAE Part Standard covers selected metric screws, hex bolts, and nuts manufactured in accordance with American Society for Testing and Materials (ASTM) and SAE fastener standards. This document covers fastener materials often used in ship systems and equipment but its use may be applied wherever fasteners of the covered materials are used. This document permits the fasteners to be identified and ordered by a part or identifying number (PIN) as defined in this document.