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Title: Operation of a test bed axial-gap brushless DC rotor with a superconducting stator

Abstract

A variable-speed axial-gap motor with a stator consisting of four liquid helium cooled superconducting electromagnets (two pole pairs) was built and proof tested up to 608 rpm in November 1990 as a tool for joint industry-laboratory evaluation of coils fabricated from high-temperature oxide superconductors. A second rotor was fabricated with improved material, winding configuration, and wire type, and the drive system was modified to eliminate current spiking. The modified motor was characterized to design speed, 188 rad/s (1800 rpm), to acquire a performance baseline for future comparison with that of high-temperature superconducting (HTS) wire. As it becomes commercially available, HTS wire will replace the low-temperature electromagnet wire in a stator modified to control wire temperatures between 4 K and 77 K. Measurements of the superconducting electromagnetic field and locked rotor torque as functions of cryocurrent and dc current through two phases of the rotor, respectively, provided data to estimate power that could be developed by the rotor. Back emf and parasitic mechanical and electromagnetic drag torques were measured as functions of angular velocity to calculate actual rotor power developed and to quantify losses, which reduce the motor`s efficiency. A detailed measurement of motor power at design speed confirmed the developedmore » power equation. When subsequently operated at the 33-A maximum available rotor current, the motor delivered 15.3 kW (20.5 hp) to the load. In a final test, the cryostat was operated at 2500 A, 200 A below its critical current. At rotor design current of 60 A and 2500 A stator current, the extrapolated developed power would be 44.2 kW (59.2 hp) with 94% efficiency.« less

Authors:
; ; ; ; ; ;  [1];  [2]
  1. Oak Ridge National Lab., TN (United States)
  2. Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
OSTI Identifier:
45492
Report Number(s):
CONF-930703-
TRN: 94:007382-0085
DOE Contract Number:  
AC05-84OR21400
Resource Type:
Conference
Resource Relation:
Conference: International cryogenic materials conference (ICMC), Albuquerque, NM (United States), 12-16 Jul 1993; Other Information: PBD: 1994; Related Information: Is Part Of Advances in cryogenic engineering, Volume 39, Part A; Kittel, P. [ed.]; PB: 1038 p.
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; SUPERCONDUCTING MOTORS; OPERATION; TORQUE; ELECTRIC MOTORS; POWER; HIGH-TC SUPERCONDUCTORS

Citation Formats

McKeever, J W, Sohns, C W, Schwenterly, S W, Young, Sr, R W, Campbell, V W, Hickey, M H, Ott, G W, and Bailey, J M. Operation of a test bed axial-gap brushless DC rotor with a superconducting stator. United States: N. p., 1994. Web.
McKeever, J W, Sohns, C W, Schwenterly, S W, Young, Sr, R W, Campbell, V W, Hickey, M H, Ott, G W, & Bailey, J M. Operation of a test bed axial-gap brushless DC rotor with a superconducting stator. United States.
McKeever, J W, Sohns, C W, Schwenterly, S W, Young, Sr, R W, Campbell, V W, Hickey, M H, Ott, G W, and Bailey, J M. Sat . "Operation of a test bed axial-gap brushless DC rotor with a superconducting stator". United States.
@article{osti_45492,
title = {Operation of a test bed axial-gap brushless DC rotor with a superconducting stator},
author = {McKeever, J W and Sohns, C W and Schwenterly, S W and Young, Sr, R W and Campbell, V W and Hickey, M H and Ott, G W and Bailey, J M},
abstractNote = {A variable-speed axial-gap motor with a stator consisting of four liquid helium cooled superconducting electromagnets (two pole pairs) was built and proof tested up to 608 rpm in November 1990 as a tool for joint industry-laboratory evaluation of coils fabricated from high-temperature oxide superconductors. A second rotor was fabricated with improved material, winding configuration, and wire type, and the drive system was modified to eliminate current spiking. The modified motor was characterized to design speed, 188 rad/s (1800 rpm), to acquire a performance baseline for future comparison with that of high-temperature superconducting (HTS) wire. As it becomes commercially available, HTS wire will replace the low-temperature electromagnet wire in a stator modified to control wire temperatures between 4 K and 77 K. Measurements of the superconducting electromagnetic field and locked rotor torque as functions of cryocurrent and dc current through two phases of the rotor, respectively, provided data to estimate power that could be developed by the rotor. Back emf and parasitic mechanical and electromagnetic drag torques were measured as functions of angular velocity to calculate actual rotor power developed and to quantify losses, which reduce the motor`s efficiency. A detailed measurement of motor power at design speed confirmed the developed power equation. When subsequently operated at the 33-A maximum available rotor current, the motor delivered 15.3 kW (20.5 hp) to the load. In a final test, the cryostat was operated at 2500 A, 200 A below its critical current. At rotor design current of 60 A and 2500 A stator current, the extrapolated developed power would be 44.2 kW (59.2 hp) with 94% efficiency.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1994},
month = {12}
}

Conference:
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