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Feature 6 | SURFACE SHIP PROPULSION
Ship-size HTS propulsion motor passes tests
American Superconductor Corporation (AMSC) and Northrop Grumman
Corporation have successfully completed full-power testing of the world’s
first 36.5MW (49,000hp) high-temperature superconductor (HTS)
ship propulsion motor.
T
he trials, at the US Navy’s
Integrated Power System
Land-Based Test Site in
Philadelphia, were the first in which an
electric propulsion motor sized for a large
combatant had been tested. The motor
was designed and built under a contract
from the Office of Naval Research (ONR)
to demonstrate the efficacy of HTS motors
as a primary propulsion technology for
all-electric warships and submarines. The
Naval Sea Systems Command (NAVSEA)
funded and led the testing effort.
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 Artist’s concept showing the reduced size of the HTS propulsion motor compared with a
motors used on the first two DDG-1000 conventional motor.
hulls and will reduce ship weight by nearly
200 tonnes, and could help make new
warships more fuel-efficient and free-up or to pack more capabilities onto fewer Performance benefits
space for other onboard systems. ships, the end result is the same: more Apart from being smaller and
“The successful load test of our HTS capability for the warfighter at less cost to lighter and more power dense than a
motor marks the beginning of a new era in the taxpayer.” conventional motor, AMSC notes that
ship propulsion technology,” claimed Dan As previously highlighted in Warship the superconducting HTS motor are
McGahn, senior vice-president and general Technolog y, in 2008, the US Navy also acoustically quiet, highly reliable
manager of AMSC Superconductors. successfully installed another HTS system and efficient.
“This motor provides the US Navy – an HTS degaussing coil – onboard USS Highlighting the advantages of the
with a truly transformational capability Higgins (DDG 76). Powered by AMSC’s new generation of AC synchronous
relative to size, stealth, endurance and HTS wire and magnet cable technology, machines, AMSC said the HTS motors
survivability, providing the US Navy with the coil system will undergo sea trials over are, on average, 35-50% of the weight
a clear performance advantage for years to the next two years onboard Higgins. of conventional synchronous motors of
come.” AMSC and Northrop Grumman As with the HTS motor, degaussing equal torque, and consume less fuel. Being
shared the work under a formal business coils utilising HTS wire would have substantially smaller and lighter than
agreement, with AMSC serving as the significantly reduced weight if fitted on their conventional counterparts, they are
prime contractor for the research and DDG 1000 destroyers, landing platform capable delivering 2-3 times more power
development phase. dock (LPD) ships, and vessels such as the per unit weight and volume than machines
“HTS technology offers the US Navy Littoral Combat Ship (LCS). that utilise conventional copper wire.
a power-dense propulsion solution, and The US Navy has invested more than HTS wire used in rotor field
it will save money,” said Donna Potter, US$100 million in the development of windings conducts electricity with
director of the Development & Integration HTS technology, paving the way not no loss of energy, as a result of which
business at Northrop Grumman’s only for use in navy ships but also in HTS motors operate at three to four
Sunnyvale, California-based Marine commercial vessels, such as cruise liners times higher efficiency at partial loads
Systems business unit. “Whether the and liquefied natural gas (LNG) tankers, than conventional AC synchronous
Navy uses the size and weight savings to which can also take advantage of the space ship propulsion motors – achieving
make ships lighter and more fuel-efficient, and efficiency benefits of HTS motors. efficiencies as high as 98% of load.
Warship Technology March 2009 33
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