China claims to have successfully tested its first permanent magnet propulsion motor for vessels recently, according to the State-owned China Shipbuilding Industry Corporation (CSIC), which is known for manufacturing China’s first aircraft carrier and the Jiaolong submersible vessel.
The motor used in conventional submarines has the power of several megawatts, but he still cannot determine the exact power of the installed test model.
Permanent magnet propulsion motor technology can replace the reduction gears and significantly reduce the running sound to the lowest possible level, the expert said.
On the global scale, the permanent magnet motor will have the power to meet the needs of full electrical movement for nuclear submarines.
Rear Admiral Ma Weiming, China’s top naval engineer, is notably responsible for the development of multiple Chinese naval electromagnetic programs, including the electromagnetic catapult and railguns. He said the Chinese navy is adding a “shaftless” rim-driven pumpjet, a revolutionary and silent propulsion system to their newest attack submarine, the Type 095 SSN.
This electric drive is an attempt to leap beyond current submarine technology to technology with a long history of attempted development. This is similar to China making a stronger commitment to develop a submersible arsenal ship. China is taking technology and designs with decades of history and actually implementing them.
Previous submarine pumpjets are “shrouded propellers,” which consist of a tubular nozzle covering the propeller. By removing the shaft of the propeller, the reduction in the number of moving parts decreases the noise made by the pumpjet, as well as saving hull space. Smaller civilian rim driven electric pumpjets are easier to maintain, and have less cavitation (bubbles that form during propeller movement), which make them even more quiet.
CCTV13 had a “Focus on the interview” segment on May 30,2017. They discussed the of electric propulsion technology power of Admiral Ma Weiming. There was some discussion of the technology and spin about how China was moving beyond copying to attempt to create breakthroughs.The first few minutes of the video discussed telecommunication switching work of Zhang Ping.
Integrated Electrical Propulsion System (IEPS) turns all the output of the ship’s engine into electricity, unlike traditional propulsion designs, which convert engine and reactor output into mechanical action to turn the propeller shaft. The high electrical output can also be used to power motors for the propellers or potentially high-energy weapons. Additionally, IEPS has far fewer moving parts, making them quieter, and thus ideal for use on submarines. When coupled with quieter reactors like the Type 095’s reported natural circulation reactor, the rim-driven pumpjet and IEPS can drastically reduce the acoustic signature of any SSN.
Yamato-1 in 1991
Westinghouse, the leading U.S. advocate, gave up in the late 1960s — because the weight required to create a sufficiently powerful magnetic field would sink most ships.
In the early 1990s, Japan succeeded in making a 100 foot long 8 mph prototype surface ship called the Yamato. A group of Japanese physicists and naval architects quickly realized that the powerful magnetic coil made possible by superconductors could transform the MHD ship from old dream to new reality. Aconsortium of universities and major high-tech firms here committed about six years ago to forge ahead with a $40 million-plus project to build the propellerless MHD ship.
US and UK have tried to get electric drive to work but have not committed to it for their next generation submarines
The US Columbia submarine and UK Dreadought will not start construction for a few years and the first unit will be ready around the 2031. They have not decided to use electric drive and may choose more conventional propulsion systems.
The US and UK military and researchers have been working on electric drive propulsion tests for at least two decades. The RED-I motor used a wet gap permanent magnet motor to turn a ring of propeller blades. Two RED-I motors are mounted in free flood areas in the submarine mud tank, forward of the stern planes. The permanent magnet motor employed is large enough to permit a four feet diameter UUV to internally pass through the RED-I propulsor system in order to deploy from the stern of the submarine.
There has been general acceptance that there is potential benefit for quieter submarines using this technology but the US has opted for more conventional approaches for quieter submarines.
Various electric motors are being or have been developed for both military and non-military vessels.Those being considered for application on future U.S. Navy submarines include: permanent magnet motors (being developed by General Dynamics and Newport News Shipbuilding) and a high-temperature superconducting (HTS) synchronous motors (being developed by American Superconductors as well as General Atomics).
More recent data shows that the US Navy appears to be focusing on permanent-magnet, radial-gap electric propulsion motors (e.g. Zumwalt-class destroyers use an advanced induction motor). Permanent magnet motors are being tested on the Large Scale Vehicle II for possible application on late production Virginia class SSNs as well as future submarines. Permanent magnet motors (developed by Siemens AG) are used on Type 212 class submarines.