SAE TECHNICAL PAPER SERIES 400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 Web: www.sae.org2002-01-1876 Prototype Low Voltage Homopolar Traction Motor T. A. Aanstoos, J. H. Beno and M. T. Caprio Center for Electromechanics, The University of Texas at Austin 2002 Future Car Congress Arlington, Virginia June 3-5, 2002Reprinted From: Pr oceedings of t he 2002 Future Car Congress on CD-ROM (FCC2002CD)Downloaded from SAE International by University of British Columbia, Saturday, July 28, 2018The appearance of this ISSN code at the bottom of this page indicates SAE’s consent that copies of the paper may be made for personal or internal use of specific clients. This consent is given on the condition,however, that the copier pay a per article copy fee through the Copyright Clearance Center, Inc. OperationsCenter, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sections 107 or108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying forgeneral distribution, for advertising or promotional purposes, for creating new collective works, or forresale. Quantity reprint rates can be obtained from the Customer Sales and Satisfaction Department.To request permission to reprint a technical paper or permission to use copyrighted SAE publications in other works, contact the SAE Publications Group. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior wr itten permission of the publisher. ISSN 0148-7191 Copyright © 2002 Society of Automotive Engineers, Inc. Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussions will be printed with the paper if it is published inSAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Group. Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 3 00 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed in USAAll SAE papers, standards, and selected books are abstracted and indexed in theGlobal Mobility DatabaseDownloaded from SAE International by University of British Columbia, Saturday, July 28, 20182002-01-1876 Prototype Low Voltage Homopolar Traction Motor T. A. Aanstoos, J. H. Beno and M. T. Caprio Center for Electromechanics, The University of Texas at Austin Copyright © 2002 Society of Automotive Engineers, Inc ABSTRACT Lower battery voltage enhances electric vehicle safety. A homopolar traction motor operates at low voltage because of its low internal impedance, and delivers torque independent of speed. A 48 VDC multi-pass, iron core homopolar traction motor was designed, fabricated, and tested in the laboratory. A MOSFET pulse width modulated controller was also designed and tested. The motor weighed 227 kg and used solid copper-graphite brushes. Laboratory testing of the motor verified the current-torque characteristic, but high brush wear prevented full speed and power demonstration. System studies show that a hybrid Ward-Leonard drive using a similar motor could yield significant cost and weight savings and improved fault tolerance over a traditional EV architecture. INTRODUCTION It has been postulated that a DC homopolar device might be preferable to a variable speed AC induction motor as a ground vehicle traction motor because 1) it is capable of developing full torque independent of speed, and 2) it is, inherently, a low voltage (safer) device. The Center for Electromechanics at The University of Texas at Austin (UT-CEM) designed, developed, fabricated and assembled, and conducted preliminary testing of a laboratory prototype homopolar traction motor (HPTM) and controller [1].