World's First Liquid Nitrogen-Cooled Full Superconducting Motor Completed

August 1, 2005

The cutting-edge Japanese academic-industrial group (*1) coordinated by Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI) has completed the world's first liquid nitrogen-cooled inductor-type flux control superconducting motor (IFCS motor).

At a time when the problems of global warming and abnormal climate change are cause for grave concern, the Kyoto Protocol has come into effect (Feb. 16, 2005). Under this protocol, Japan is required to reduce its greenhouse gas emissions between 2008 and 2012 by 6% of the emission level in the reference year (1990). (A 14% reduction is actually considered necessary, averaged over the 2008-12 period.) Legal controls on automobile exhaust emissions are already in place, and similar controls are expected to be imposed on ships sooner or later. The academic-industrial group has developed the full superconductor motor as a power plant capable of meeting such controls.

Superconductivity, which can reduce electric resistance to zero, makes possible waste- less utilization of energy, eliminating the discharge of heat into the atmosphere and thereby reducing adverse impacts on the natural environment. Moreover, compared to a conventional wire, superconductivity facilitates the flow of more than 200 times as much electricity, thereby reducing the size and weight and improving the economy of equipment.

A ship equipped with the superconducting pod propulsion system mentioned above is estimated to reduce its annual CO2 emissions by about 11% (for operations involving frequent port calls).

Superconducting motors are about 10% more efficient than conventional motors used on shore, and accordingly will make a significant contribution to conservation of scarce energy resources.

It is hoped that these economical, environment-friendly superconducting motors will be installed in many ships and on-shore plants, doing their part to reduce emissions of greenhouse effect gases while reducing energy consumption.
The recently unveiled product is an epoch-making full superconducting motor, representing as it does the first ever application of superconducting technology to both the field and the armature coils. It can virtually eliminate wasteful energy consumption by the motor, the size and weight of which can be reduced dramatically.

Previous attempts around the world to develop a superconducting motor have run into three major problems, and the experience of the Japanese group was no different. However, by adopting an unconventional approach, the group succeeded in resolving these problems, completing the world's first full superconducting motor.


Problem 1: Achieving superconductivity when using helium or neon gas, as the coolant requires a large, complex structure to capture the coolant's negative heat, meaning that neither the size nor the weight of the motor can be reduced.
Solution: The group developed a mechanism to allow the motor to operate even if liquid nitrogen, which has a higher temperature than helium or neon, was used, and succeeded in simplifying the heat-insulating structure, resulting in a dramatic reduction in the motor's size and weight.
Size is 1/10 that of a conventional motor with an output of 5000 kW (the world first)

Problem 2: Since superconductivity is susceptible to the adverse effects of magnetism, no superconducting motor could be realized until some way was worked out to nullify the effects of the latter.
Solution: A Flux Collector (FLC; trademark registration pending) was conceived to solve this problem. The FLC is a mechanism featuring a highly permeable material in the core of the coil that protects the coil from the effects of magnetism by inducing the magnetic flux to intensively pass that material.
Completion of a full superconducting motor (the world first)

Problem 3: All earlier superconducting motors were designed with superconducting parts that revolved as movable elements of the motor; this design requires a mechanism to allow coolant to flow in via the shaft, reducing the motor's reliability and ease of maintenance. As such, realization of a motor whose superconducting parts did not turn was the goal.
Solution: All superconductive parts have been fixed in place, and a revolving part has been added as an inductor. Since the inductor has no coil, it does not bleed energy.
High reliability and freedom from maintenance have been realized (fixed superconducting parts - another world first).


Solving the unsolvable has resulted in the following additional features.
1. Ultra-quiet (noiseless) motor: It is so quiet that operation of the motor may go unnoticed. This is a dream motor that, if mounted on a parcel delivery truck, would relieve residents along the truck's route from engine noise and exhaust emissions.
2. Although the motor contains a very strong electromagnet, it has no external influence (no magnetic flux leaks). It is a motor that even cardiac pacemakers could live with (verification in progress).
3. Though the inside of the motor is cryogenic, its surface is kept at normal temperature. Even if used in water, the motor presents no risk of freezing. Combined with its small size and large capacity, this non-freezing characteristic might realize the dream of running a large ship as fast as a car.
4. It makes possible double structuring of the motor shaft. Such a feature would enable two motors to be connected in tandem and yet revolve in opposite directions. The world's first superconducting contra-rotating propeller is scheduled for realization next year. The contra-rotating propeller could achieve additional saving in terms of energy consumption (by over 10%). Use of such propellers by the world's ships would yield a significant leap forward in the battle against global warming.

Because of these remarkable features, this new concept in motors is expected to find effective application as a marine electrical propulsion system, railroad motor and many others.

IHI established a new business department, "Superconductive Ship Propulsion System Div.," and started the sales activities of the Integrated Power System (IPS) using the world's first inductor-type flux control superconducting motor (IFCSM), or Full Superconducting Motor. IHI is now building an 800kW pod propulsion system consisting of two-400kW IFCSM for verification tests. These motors are arranged in tandem to allow two propellers contra-rotation. The test unit will be completed by the end of 2005. The three-month verification tests will begin using a dock of a shipyard in January 2006. The active sales of the IPS are now expected to start the second half of fiscal 2006.



Note:(*1)
Ishikawajima-Harima Heavy Industries Co., Ltd., Sumitomo Electric Industries Co., Ltd.,
Taiyo Nippon Sanso Corporation, Nakashima Propeller Co., Ltd.,
Niigata Power Systems Co., Ltd., Hitachi, Ltd.,
Professor Hidehiko Sugimoto of Fukui University,
and Fuji Electric Systems Co., Ltd.