NASA Logo, External Link
Facebook icon, External Link to NASA STI page on Facebook Twitter icon, External Link to NASA STI on Twitter YouTube icon, External Link to NASA STI Channel on YouTube RSS icon, External Link to New NASA STI RSS Feed AddThis share icon
 

Record Details

Record 1 of 22542
High Power Density Motors
Author and Affiliation:
Kascak, Daniel J.(Ohio Univ., Dept. of Mechanical Engineering, OH, United States)
Abstract: With the growing concerns of global warming, the need for pollution-free vehicles is ever increasing. Pollution-free flight is one of NASA's goals for the 21" Century. , One method of approaching that goal is hydrogen-fueled aircraft that use fuel cells or turbo- generators to develop electric power that can drive electric motors that turn the aircraft's propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are far too heavy (for a given horsepower) to use on aircraft. Fortunately the liquid hydrogen fuel can provide essentially free refrigeration that can be used to cool the windings of motors before the hydrogen is used for fuel. Either High Temperature Superconductors (HTS) or high purity metals such as copper or aluminum may be used in the motor windings. Superconductors have essentially zero electrical resistance to steady current. The electrical resistance of high purity aluminum or copper near liquid hydrogen temperature can be l/lOO* or less of the room temperature resistance. These conductors could provide higher motor efficiency than normal room-temperature motors achieve. But much more importantly, these conductors can carry ten to a hundred times more current than copper conductors do in normal motors operating at room temperature. This is a consequence of the low electrical resistance and of good heat transfer coefficients in boiling LH2. Thus the conductors can produce higher magnetic field strengths and consequently higher motor torque and power. Designs, analysis and actual cryogenic motor tests show that such cryogenic motors could produce three or more times as much power per unit weight as turbine engines can, whereas conventional motors produce only 1/5 as much power per weight as turbine engines. This summer work has been done with Litz wire to maximize the current density. The current is limited by the amount of heat it generates. By increasing the heat transfer out of the wire, the wires can carry a larger current and therefore produce more force. This was done by increasing the surface area of the wire to allow more coolant to flow over it. Litz wire was used because it can carry high frequency current. It also can be deformed into configurations that would increase the surface area. The best configuration was determined by heat transfer and force plots that were generated using Maxwell 2D. Future work will be done by testing and measuring the thrust force produced by the wires in a magnetic field.
Publication Date: Jan 01, 2004
Document ID:
20050186593
(Acquired Jul 12, 2005)
Subject Category: SPACECRAFT PROPULSION AND POWER
Document Type: Conference Paper
Publication Information: Research Symposium II; (SEE 20050186580)
Meeting Sponsor: NASA Glenn Research Center; Cleveland, OH, United States
Financial Sponsor: Ohio Univ.; Dept. of Mechanical Engineering; OH, United States
Organization Source: Ohio Univ.; Dept. of Mechanical Engineering; OH, United States
Description: In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: GLOBAL WARMING; HYDROGEN FUELS; LIQUID HYDROGEN; HIGH TEMPERATURE SUPERCONDUCTORS; ELECTRIC MOTORS; TURBINE ENGINES; NASA PROGRAMS; REFRIGERATING; HEAT TRANSFER
Availability Source: Other Sources
Availability Notes: Abstract Only
› Back to Top
Find Similar Records
NASA Logo, External Link
NASA Official: Gerald Steeman
Site Curator: STI Program
Last Modified: August 23, 2011
Contact Us