Superconducting motor to increase power density

May 24, 2007 By Lisa Zyga feature
Superconducting motor to increase power density

The scientists’ experimental setup: (1) stationary cryostat; (2) induction motor; (3) belts; (4) sliding, contacts—(a) brushes, (b) rings. Image credit: Ailam, et al. ©IEEE 2007.

The field of electric motors has recently entered a new era. The electric motors that you see today in everything from washing machines, toys, and fans use the same basic principles as motors from 50 years ago. But with the realization of using superconducting wire to replace conventional copper coils, motors are becoming more compact, more energy efficient, and less expensive, which will have advantages particularly for large industrial applications.

Recently, scientists El Hadj Ailam and colleagues working at the Université Henri Poincaré in Nancy, France and the Center for Advanced Power Systems in Tallahassee, Florida, have designed and tested a superconducting rotating machine based on an unconventional topology. Their results, which are published in IEEE Transactions on Applied Superconductivity, show promising opportunities for the motor.

“This work has two goals,” Ailam, who is currently with the Centre Universitaire Khemis Miliana in Algeria, told PhysOrg.com. “The first is to show the feasibility of an electrical motor based on the magnetic flux density, and the second is to demonstrate that superconductors can significantly ameliorate the electrical machine performances.”

Building on high-temperature motors designed over the past few years, Ailam et al.’s motor is a low-temperature, eight-pole machine with a stationary superconducting inductor. Unlike copper coils, the niobium-titanium (NbTi) inductor coils in this design have no electrical resistance, which is one of the greatest advantages of superconductors.

When the two NbTi coils are fed with currents moving in opposite directions, the currents create a magnetic field. Located between the two coils, four superconducting bulk plates (made of YBaCuO, or yttrium barium copper oxide) shape and distribute the magnetic flux lines, which then induces an alternating electromagnetic field based on the magnetic concentration. A rotating armature wound with copper wires then converts the electrical energy to mechanical energy, which is eventually transferred to an application.

In this design, the entire inductor is cooled to 4.2 K using liquid helium to enable zero electrical resistance in the coils. (The scientists explain that high-temperature wires could also work in this configuration.) As with all superconducting motors, the superconducting wire can carry larger amounts of current than copper wire, and therefore create more powerful magnetic fields in a smaller amount of space than conventional motors.

“For the majority of electrical superconducting machines, the structure is a classical one, and the magnetic flux is a radial one,” Ailam explained. “[However,] for our machine, the inductor magnetic flux is an axial one.”

To test the performance of the motor, the scientists calculated the magnetic scalar potential, which tells the strength of a magnetic field in a certain area, and then determined the magnetic flux density, which is the quantity of magnetism in that area. As the scientists explained, the maximal value of the flux density exists in between two of the bulk plates, while the minimum value exists behind the plates; a large difference in magnetic flux density maximizes the motor’s performance by generating a more powerful magnetic field.

The group experimentally demonstrated a performance of 118.8 volts for the motor. Further, they calculated a theoretical generated voltage of 172.5 volts, and explained that the difference is due to an uncertain value for the difference in the maximal and minimal values of the magnetic fields around the bulk plates, which was not directly measured. Improving this difference in magnetic flux density will hopefully increase the motor’s voltage.

“As we demonstrate in another paper, under realization, using this structure with several superconducting wires and 20 mW generated power decreases the inductor volume 20-50 percent in comparison to a classical electrical machine,” Ailam said.

In the near future, the group plans to design and construct a 100 kW superconducting machine using the same configuration.

“The major advantages of these motors are a high power-volume density and a high torque-volume density, and less vibration than for the conventional motors,” Ailam said. “I think that the maritime propulsion can and the electrical traction generally can benefit principally to these motors.”

Citation: Ailam, El Hadj, Netter, Denis, Lévêque, Jean, Douine, Bruno, Masson, Philippe J., and Rezzoug, Abderrezak. “Design and Testing of a Superconducting Rotating Machine.” IEEE Transactions on Applied Superconductivity, Vol. 17, No. 1, March 2007.

Copyright 2007 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

4.2 /5 (92 votes)  

Rank 4.2 /5 (92 votes)
Tags

Relevant PhysicsForums posts
  • Empirical data regarding shower heads and water
    created4 hours ago
  • feed hold button on CNC lathe
    created23 hours ago
  • RFAC in Fortran
    createdFeb 09, 2012
  • dynamics 2/32
    createdFeb 08, 2012
  • dynamics
    createdFeb 08, 2012
  • Vibration Absorbtion Problem
    createdFeb 08, 2012
  • More from Physics Forums - General Engineering

More news stories

US video game sales fall 34 percent in January

(AP) -- U.S. retail sales of video game hardware, software and accessories fell 34 percent in January from a year earlier to $751 million due to the lack of new game titles, according to market researcher NPD Group.

Technology / Business

created 46 minutes ago | popularity not rated yet | comments 0

Zynga partners with toy maker Hasbro

Old school toy maker Hasbro and online social game star Zynga on Thursday announced a partnership to mesh the Internet firm's hits with real-world products.

Technology / Business

created 5 minutes ago | popularity not rated yet | comments 0

Samsung can continue selling Galaxy tabs in Germany: court

South Korea's Samsung Electronics can continue to sell its Galaxy Tab 10.1N tablet computer in Germany, a German court ruled Thursday, rejecting a bid by arch-rival Apple to have them banned.

Technology / Business

created 22 hours ago | popularity 4 / 5 (4) | comments 3

Digital photos could put kids at risk

A study published in the International Journal of Electronic Security and Digital Forensics this month suggests that parents and carers could be putting children at risk if they upload digital photos that are automatically "geota ...

Technology / Internet

created 18 hours ago | popularity 5 / 5 (1) | comments 3

Google launches Chrome browser for Android smartphones

With more and more people connecting to the Internet through a phone or a tablet instead of a PC, Google Inc. is bringing its fast-growing browser, Chrome, to the newest Android-powered mobile devices.

Technology / Software

created 20 hours ago | popularity 5 / 5 (5) | comments 0


Humans may have helped the decline of African rainforests 3000 years ago

(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...

Japan scientist makes 'Avatar' robot

A Japanese-developed robot that mimics the movements of its human controller is bringing the Hollywood blockbuster "Avatar" one step closer to reality.

Fighting crimes against biodiversity: How to catch a killer weed

Invasive species which have the potential to destroy biodiversity and influence global change could be tracked and controlled in the same way as wanted criminals, according to new research from Queen Mary, University of London.

Metastatic breast cancer hitches a free ride from the immune system

Inflammatory breast cancer (IBC) is the most lethal form of breast cancer . It spreads easily through the lymphatic and blood vessels, forming metastasis which can lead to multi-organ failure. New research published in BioMed ...

A novel method for simultaneously measuring blood pressure and arterial stiffness

Arterial stiffness due to is a major contributor to cardiovascular disease but is very difficult to measure. It also can influence blood pressure readings since these rely on the time taken for arteries to return to normal ...

Sleep breathing machine shows clear benefits in children with sleep apnea

Children and adolescents with obstructive sleep apnea had substantial improvements in attention, anxiety and quality of life after treatment with positive airway pressure (PAP)—a nighttime therapy in which a machine ...