A Big Motor For The Electric Navy
Superconducting Motor

Last week I did a post on the the science of electric motors that featured a learning kit for kids that provided the parts required for a kid (of any age) interested in the science and technology of electric motors to build a small one. I'd estimate that the motor, which you could hold in the palm of your hand, produced less than 1/1,000th of a horsepower. Here is a motor whose power is about ten orders of magnitude bigger. And that is a whole lot bigger.

The Next Big Future reports on the really big motor that uses high temperature superconductors.

American Superconductor Corporation, a leading energy technologies company, and Northrop Grumman Corporation announced today at the Surface Navy Association's 21st National Symposium the successful completion of full-power testing of the world's first 36.5 megawatt (49,000 horsepower) high temperature superconductor (HTS) ship propulsion motor at the U.S. Navy's Integrated Power System Land-Based Test Site in Philadelphia. This is the first successful full-power test of an electric propulsion motor sized for a large Navy combatant and, at 36.5 megawatts, doubled the Navy's power rating test record.
The Business Wire tells a little more of the story.
This system was designed and built under a contract from the Office of Naval Research to demonstrate the efficacy of HTS motors as the primary propulsion technology for future Navy all-electric ships and submarines. Naval Sea Systems Command (NAVSEA) funded and led the successful testing of the motor.

Incorporating coils of HTS wire that are able to carry 150 times the power of similar-sized copper wire, the motor is less than half the size of conventional motors used on the first two DDG-1000 hulls and will reduce ship weight by nearly 200 metric tons. It will help make new ships more fuel-efficient and free up space for additional warfighting capability.

"The successful load test of our HTS motor marks the beginning of a new era in ship propulsion technology," said Dan McGahn, senior vice president and general manager of AMSC Superconductors. "This motor provides the U.S. Navy with a truly transformational capability relative to size, stealth, endurance and survivability, providing our Navy with a clear performance advantage for years to come. We are grateful for the steadfast support from the Office of Naval Research, Naval Sea Systems Command and the Naval Surface Warfare Center."

A different branch of the Navy, Naval Air Warfare Center Weapons Division, is funding work that may lead to a shipborne fusion power reactor. Which would be kinda handy to have to power two or four of those electric motors turning the screws of an aircraft carrier. You can read about the latest contract for development of the Bussard Naval Fusion Reactor at IEC Fusion Technology.

And that is not the only electric propulsion system that future aircraft carriers will use. There is also the electric catapult being developed by General Atomics (GA).

GA and its Team have completed the Program Definition and Risk Reduction (PDRR) phase of the Navy's electromagnetic aircraft launch system (EMALS) program and have been selected to perform the System Development and Demonstration phase. The goal of the EMALS SDD phase is to develop the existing design chosen during PDRR into an integrated shipboard system that is both operationally suitable and effective, thus replacing steam catapults with an electric system that will reduce maintenance and provide flexibility and growth potential for carrier aviation throughout the 21st century.The GA Team EMALS design is a robust, highly reliable launch system that will meet or exceed all Navy performance goals. This design will provide significant reductions in installed weight, volume, and workload compared to the existing steam catapult. The design uses state-of-the-art technologies that we believe will demonstrate our system is affordable and producible.
There are more details at the link.

And guess what else the US Navy is working on? A real honest to God beam weapon. The Free Electron Laser

The Navy is pushing ahead with a five-year, $163 million dollar plan to bring the "Holy Grail" of energy weapons up to battlefield strength.

For decades, scientists have been slowly working on a laser that never runs out of shots -- and can be "tuned" to blast through the air, at just the right wavelength. For most of that time, all they could get was a laser at lightbulb-strength. But in 2004, researchers at the Thomas Jefferson National Accelerator Facility finally managed to assemble a "Free Electron Laser," or FEL, that could generate 10,000 watts of power. Now, the Navy has started an effort to design and build a new FEL, 10 times as strong. That would bring the laser up to 100 kilowatts -- what's considered the minimum threshold for weapons-grade. But it would also be just a stepping stone, on the way to an energy weapon as powerful as any produced. If ray gun researchers can get the thing to work, that is.

And lest we leave out projectile weapons how about an offshoot of the electric aircraft catapult. The rail gun which fires projectiles with electricity at a muzzle velocity of better than 8,000 ft per second.
The Navy is researching rail guns because they would weigh less than conventional ones, and since they rely on electromagnetics to fire rounds, you wouldn't need a big, dangerous pile of explosives stored in a magazine. All of that means a lighter ship, and a much more deadly ship: a combat-ready rail gun would be able to fire Mach 5 projectiles over 200 miles with pinpoint accuracy, hitting 5 meter targets.

Yesterday's test firing at the Naval Surface Warfare Center Dahlgren Division used just some of the potential 32-megajoules the laboratory test gun is capable of, and that's only half the 64-megajoules the Navy is aiming at for the final weapon.

If you follow the link you can watch some really cool videos.

It looks like the US Navy has a plan. And you know? I just love it when a plan comes together.

H/T just_an_observer at Talk Polywell

Cross Posted at Power and Control

posted by Simon on 01.14.09 at 12:07 PM


Don't get me wrong, I'm all for having energy weapons but....
I wonder if the laser could be used to transmit energy in usable form.
Like making solar collectors in space and beaming the collected power down to Earth.

Veeshir   ·  January 15, 2009 9:24 AM

Liked the write-up. Question: How is the power generated for the super-big HTS electric motors?

dave   ·  January 16, 2009 12:56 PM


Gas turbines are the current (heh) standard for oil burners.

For steam ships (including nukes) the turbines will be direct coupled to a generator eliminating reduction gears, shafts, and shaft alleys.

Turbines will be run at constant speed. Electronic converters will control the motors. At least that is how I would do it. Constant speed turbines are easier to design.

M. Simon   ·  January 16, 2009 1:24 PM

And the beauty of all of this is, the power electronics required to pull it all off is so big, so heavy, and so expensive, that they need a second ship following the first just to house the electronics, but they can only afford to build a single ship in each class. I worked in these programs for a number of years, and they are hopeless. Sure, they are full of great ideas, but they are hopelessly complex, they never bother to test any of the concepts against reality, always wanting to go to bigger and more complex systems instead.

I worked on the design of a new destroyer class that was to be all electric. It is so expensive that they are building one (1) ship for the whole class! Zillions of dollars of development for a new ship class, and we can only afford to build one ship! But that is probably just as well because it will be a fiasco.

The Navy does not ever believe in taking an idea out and making it operational on an existing ship. No, that would be too simple! They have to incorporate all their good ideas in a new ship design, and everything get more and more complex.

All electric sounds so nice. There will be no more leaking hydraulics, no more messy, hard to control steam, no more pneumatics, just nice, clean simple electrical systems. Well, it is not quite that simple. The energy density of a hydraulic cylinder is a lot higher than an electric motor in most cases, and if you need to turn a shaft at low speed, such as to turn a control surface, a hydraulic cylinder is ever so much easier to use than an electrical device. Sure, there are electrical ball screws, and other similar devices, but the energy density and power density is just not there. I have spend years researching this, along with a lot of other people. But when it has to be all electrical, well ....

And then how do you distribute all that electrical power around the ship. You can't just run an extension cord from the generator to your application. It gets to be quite a problem to distribute large amounts of power on ship board (we are talking many megawatts) by electrical cable. Do you do it as AC, or DC, at what frequency, at what voltages? Mind you, we are talking about enough power to drive the ship, so this is the power that previously was transferred through large steel shafts, but now has to go through electrical cables. It is tough!! (And expensive, and heavy, and takes a lot of space!)

Dr.D   ·  January 17, 2009 6:46 PM

Dr. D,

When did you last work on power electronics? A few advances may have probably been made since then.

4.5KV @ 2,400 A IGBTs are available. 3 in series should be good for 10KV (6.6KV RMS) operational. Six such modules should work for making 3 ph AC at the required frequencies. That is 18 IGBTs. Or 36 if you want a more conservative design re: current.

As to electric drives for ships. A lot of folks seem to be making them:


As to power distribution: superconducting cables of course.

DC is good. You convert it at the point of load. The Space Station has a DC Bus. Around 300VDC IIRC.

By getting rid of shafts, shaft alleys, and reduction gears you save a lot of volume and weight.

By better matching load to engine speed (the engine can run at constant speed) you save on life cycle costs (fuel) even if initial costs are higher. And the fuel savings translates into longer operational range or reduced at sea refuelings.

M. Simon   ·  January 17, 2009 9:49 PM

I retired from the Naval Surface Warfare Center-Phila in summer 2006, so that is about 2-1/2 years ago.

Simon, you make it all sound so simple. Which contractor do you work for? Everyone of them can tell you that is is a piece of cake, but when push comes to shove, there are always problems.

One of the things few folks think about is the area of survivability. What happens when a combat ship is hit? The distribution system needs to provide for alternate routing of power, and at the same time for the isolation of areas where fire fighting and other damage control is underway. Superconducting cables don't work too well when you have taken a hit on the port side, but you still have to have power (you cannot afford to loose power just because the super conductive cable quenches!).

Yes, there are good points to the all-electric idea, but there are huge problems with it as well.

My biggest objection, however is this: The US Navy never, ever, takes a single system to an existing platform and gets it to work there, rather than simply specifying it as a part of a new, super-duper platform. Thus the new ship platform is burdened with an almost endless list of untried systems, none of which have ever been made to work at full scale on a ship. Thus the design of the new ship is a fantastic compromise of what is best for the ships drive, versus what is required for the electric armor, versus what will be required for the rail gun, versus what will be required for the gee-whiz radar, versus ...., none of which are known to work at all under the best of circumstances. It is all just a big boondoggle, an empire building enterprise to keep a bunch of incompetents in government and industry on high salaries. I think that they are careful to always keep reaching for the sky, beyond the realm of possibility, so that they never really have to produce.

Dr.D   ·  January 18, 2009 8:20 PM

Oh, by the way, Simon, 3-phase AC is sooo... 20th century for large power! These big motors are many, many phases, which means lots and lots of IGBTs (with water cooling and the fun that entails!). The heat load from all the power electronics is pretty substantial for running one of those big machines, before we ever get to the motor itself.

Dr.D   ·  January 18, 2009 8:29 PM

Dr. D.,

Well, I'm sure now you don't know what you are talking about. The motors are 3 phase 6 pole. You didn't even read the article.

EMALS - a linear motor - probably has multiple phases.


All the Navy vessels I knew had port and starboard electrical, water, etc. distribution.

They also had backup generators for emergency power.

I would imagine that there would also be a low power AC distribution network with copper wires. For emergency pumps etc.


As to full scale testing: that is being done on land in the same way the nuke stuff was done. Full scale mock ups.

Shock testing was done with explosives.


BTW the Brit Navy has had the 45 Class of destroyers for a while. The first of the Class started sea trials in 2007. Electric drive.

Cruise ships use electric drive.

M. Simon   ·  January 18, 2009 9:16 PM

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