Sumitomo Electric & Japanese Partners developed the World's first All HTS Motor

Author: admin / 2005-04-10

Sumitomo Electric and Japanese Partners have developed the world's first All High Temperature Superconducting Motor (HTS Motor). All the coils in this motor are made from bismuth based high temperature superconducting wire. The motor is cooled by liquid nitrogen to make the system economical. The motor has been successfully tested and demonstrated at IHI Yokohama works from April 14th. to April 28th. 2005.

The HTS Motor offers following features:
Uses "Off the Shelf" Superconducting Wires
This motor employs bismuth-based superconducting wires that can be fabricated in lengths of several kilometers through Sumitomo's innovative process. The motor is ready to go to mass production stage.

1. Economical Operation
HTS scarcely produces losses during operation. Use of liquid nitrogen as the cooling medium makes the system small and economical.

2. Small but Powerful
HTS with newly developed Flux Collector (FLC) makes the motor small but powerful.

3. Room Temperature Surface
Water does not freeze when this motor is equipped in a POD ship propulsion system. Super-high speed ships will be launched shortly employing this HTS motor.

4. Capability of Double Concentric Shaft
Realization of a contra-rotating propeller for ship propulsion system with combination of tandem configuration of this motor is feasible. This contra-rotating propeller can reduce fuel consumption up to 10%。World-wide use of this motor in all ships contributes to considerable reduction of carbon dioxide gas discharge.

5. Extremely Low Noise, Low Vibration
This low noise feature is attractive when this motor is applied to delivery trucks. 

6. Low Leakage Flux
Magnetic flux is confined in FLC and the flux scarcely affects human health. 

Sumitomo and partners plan to commercialize the 400kW-220rpm motor.It is expected to be available for sale in 2005 following verification tests.
Development of the contra-rotating propeller will also be started in 2006.Sumitomo and partners are also planning the manufacture of a motor over5000kW capacity 


Technical Note

Superconducting wire is considered to be the best approach to reduce losses in electrical machinery such as electrical motors.It is, however, difficult to manufacture a rotor or the motor using superconducting wire due to the complicated structure of the motor. Such a structure requires flow channels of cooling mediums 
through a rotating joint. 

The complicated structure reduces reliability and ease of maintenance. Superconducting coils of exciters and armatures used in this motor are fixed to a motor frame to avoid the issue. Inductors are installed as the rotor instead and reduce losses as there are no coils. This motor is called Inductor type Flux Control Superconducting motor (IFCS). The simple structure of this motor realizes high reliability and ease of maintenance.

Since the magnetic field limits and affects superconducting conditions, the realization of electrical equipment using bismuth based superconductor has been considered difficult at the liquid nitrogen temperature. To eliminate this problem ,Sumitomo and Partners have developed Flux Collector (FLC). This is a high permeable material which is positioned at the center of the coils to gather magnetic flux and enables reduction of magnetic flux on the coil.

Whilst the superconductor is operating at liquid nitrogen temperature it is possible to reduce the size of the cooling system and thickness of the thermal shield. Liquid nitrogen is easy to acquire at a reasonable cost. These features collectively enable the invention of a small and light superconducting motor.

This development has been undertaken by:
Sumitomo Electric Industries Ltd
Fuji Electric Systems Co. Ltd
Hitachi Ltd
Ishikawajima - Harima Heavy Industries Co. Ltd
Nakashima Propeller Co. Ltd
Niigata Power Systems Co. Ltd
Taiyo Nippon Sanso Corporation
University of Fukui (Prof. Hidehiko Sugimoto)

------from :Sumitomo Electric Industries.