FIRSTCADLIBRARY.COM

Robotic Cad Files, 3D Modeling, Solid Works, AutoCad, Inventor

    

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First Cad Library of 3D Components and Robotic Design Files

First Cad Library

Welcome to my CAD library of robot components . Here you will find many models of the components used in current and prior FIRST robotic competitions as well as some other useful information. This includes all motion control and indexing components, servo driver electronics, motor selection and additional information on both hardware and software available. i-Models are included in the libraries and take advantage of Inventor 6's iFactory feature. i-Models are made up of graphic elements that are attached to tables of dimensions. Each i-Model contains many versions of a base part. For example, If you insert the i-Sprocket Model into an Inventor Assembly, you will be asked for the number of teeth, the bore diameter, and keyway details. The iFactory feature of Inventor will then generate the customized part and insert it into your assembly. The i-Models are identified with a i in the lower right corner of the thumbnail. Notes for first time users: This site now supports mutiple CAD file types primarily the most popular which is AutoDesk's Autocad. Just click on the file type button next to the thumbnail to download the part model. All Autocad models have been converted to R14 and all Inventor Models are R5 or R6. Manufacturer's web site links have been added. Click on the thumbnail of a part to open the manufacturer's web page (when available). "New", "Updated", and "Obsolete" icons to help you know when a model has changed status.

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3D Solid Modeling of High Performance Electric Motors for Aerospace

50,000 RPM, High Power and Torque Electric Induction Motor designs

Designing an high speed turbo powered electric motor system with capability of up to 50,000 RPM at a continuous rate of speed is quite an engineering challenge. Especially if it is for aircraft design and usage. The weight to size ratio is of extreme importance as with anything that is to be used for aviation or aerospace type applications. Other high performance machine designs included such as turbo compression systems in gas turbines, flywheel energy systems, surgical drills and high speed spindles for machine composite materials.

The overal physical and mechanical constraints imposed with designs whose maximum circumferential speed that reaches or exceeds the speed of sound are critical. Typically and historically permanent magnet type synchronous machines (PMSMs) have been used in past designs, though mostly 2D. According to this and including information up to 2010, there have been no simulations, prototype tests, or industrial applications made in compliance with the requirements in Table I. The power range and the speed have been reached (and even exceeded) separately, but never simultaneously. According to [17], in the range of high power, more motors are designed for induction machines (IMs) than for PMSMs, which are mainly found in generator applications.

The world record speed attained by an electric motor is now at over 1 million rpm. For efficiency in aerospace and aviation requirements a minimum of 50000 rpm is required with power of less than 7 Kilowatts and a 92% efficiency. These designs are reviewed with real-time software 3D modeling to observe and correct dynamic problems associated with vibration and torque at high speeds. Wear and damage caused by corrosion is critical. In-situ testing of bearings, circumferential speed and stress induced is part of the design process and included in the final 3D modeling design decision.

A superior machine is analyzed both with 3D modeling software and simulation software to produce analytical tools needed to produce the most efficient and exacting engineering design approach prior to manufacturing. Materials Properties must be carefully considered, and heat generation caused by friction and component degradation over fixed periods of time must also be considered.

An induction based motor or machine (IM) using the typical squirrel-cage rotor for example is more susceptible to problems than a solid rotor from the mechanical design considerations necessary to prove the concept. Whereas the slip ring rotor is undesirable for it's use of carbon brushes- and potential fire ignition from sparking. Permanent magnet synchronous machine motors and brushless DC motors both supplied with sinusoidal current instead of square wave DC that is used in brushless DC Motors. This design yields a lower torque ripple effect and acoustic resonance behaviors more conducive to high performance designs. Materials historically that contain high power to weight density over mass are normally reserved for gas turbines such as waspalloy, inconel, titanium and graphic epoxy carbon fiber are more pervasive to be used in these 3D designed assemblies.

Other designs of motors include: Switched reluctance machine designs, Synchronous reluctance machine (SynRM) and Homopolar and heteropolar machines and Transverse flux machines. Piezo Electric drive and traveling wave engine, are better suited than Linear Motors. Currently the maximum current density between 15-22 A/mm² ensures safe, thermal damage free operation. Rotor slots with a closed type design can withstand with higher centrifugal force since the stress distribution is spread. Another factor is that of breakdown torque, varying inverse to the leakage reactance. Again, thermal considerations in 3D design must be factored in.