As the future becomes increasingly electric, electric motor manufacturers are constantly searching for new ways to achieve greater output from their designs. Independent start-up DHX Electric Machines Inc. might have just found the answer with its innovative micro-feature enhanced Direct-Winding Heat Exchange (DWHX™) cooling system.
The company, specializing in ultra-high torque density electric machines, was founded in 2014, based on technology developed at the Georgia Institute of Technology.
"Our proprietary technology takes advantage of a unique ability to remove extraordinarily high levels of heat, and we apply that in a way where it is directly connected to the windings of the electric machine (thermally, not electrically)," says CEO and president Dr. J. Rhett Mayor, who is also a professor at the Woodruff School of Mechanical Engineering.
"That's where our name comes from - direct winding heat exchange," he continues. "From the beginning, our target was simply to maximize the amount of heat you can take out of the winding. To do that, our cooling technology uses a micro-feature-enhanced heat exchanger."
The DWHX™ cooling system is situated directly at the heat source - the stator windings. Using micro-feature enhancement, it is capable of removing up to 25 times the heat of conventional cooling systems. Consequently, it provides a five-times increase in torque per volume, allowing DHX electric motors to produce the same torque in 75% of the space of the conventional motor.
"As far as we know, people have developed other cooling solutions using air, water, direct lamination cooling - people have even run a cooling tube down by the coil - but no one has successfully managed a direct heat exchange like we have," Dr. Mayor affirms.
At present, DHX Electric Machines has three ranges of electric motors: the Hawk, Kestrel and Falcon. The Hawk series incorporates low voltage traction power (48-60 volts).
"The Hawk20 operates on a 48-volt source," Dr. Mayor says. "It will deliver 15 kilowatts of peak power and 7.5 kilowatts of all-day, every-day power. The amount of time you can stay at peak power depends on the power of your cooling system. These motors are generally used in golf carts, electric utility vehicles, and neighborhood electric vehicles - an area of the market that I see growing exponentially in the coming years. Similarly, the 60-volt Hawk60 has a lot of potential in the marine markets."
The Kestrel series mainly comprises industrial motors, which currently account for roughly 85% of the market. "The Kestrel series is perfect for wash down motors; cooling tower motors; and heating, ventilation and air conditioning (HVAC) - these are all exciting industries for us."
Finally, the Falcon series focuses on automotive passenger vehicle applications. DHX is currently developing ultra-high torque density motors for light trucks and buses and other applications in the transportation sector.
A concept that Dr. Mayor is particularly interested in is sustainable mobility. "This term has been around for a long time but I think we have a very interesting confluence of opportunity at the moment," he says. "Low voltage traction motors could provide a completely renewable neighborhood mobility solution - a legitimate green electron supply using solar and wind power battery regeneration. Our 48-volt Hawk models are doing this right now.
"The ‘golf cart solution' is already seeing success in the US as a viable alternative to vehicles powered by internal combustion engines. The development of ‘lifestyle paths' - mini roads where you can cycle and also use small electric vehicles - are helping this to become a reality. I believe that application spaces will open dramatically in the next three to five years," stated Mayor.
Having previously presented numerous invited seminars and keynote addresses on various topics within the field of micro-manufacturing and energy systems, Dr. Mayor will be speaking at CWIEME Chicago 2017. The leading exhibition for coil winding, transformer and electric motor manufacturing will take place at the Donald E. Stephens Convention Center, October 3-5.
His seminar, entitled ‘Motoring into the future by incorporating the patented Direct Winding Heat Exchange (DWHX) cooling technology' will take place between 12:10 - 12:50 on October 3 in the CWIEME Connect Theatre. DHX Electric Machines will also be exhibiting at booth E43.
"We will start off exploring the physics behind the cooling technology of the DHX motors," says Dr. Mayor. "After that, we'll move into a couple of areas that I think are very exciting for the electric motors world. We'll discuss the role of electric machines in the global trend towards ‘sustainable mobility' and what we believe the future opportunities will be in that field.
"We will consider where the industry is going and what new application spaces will open up in the future based on liquid cooling systems and the associated new levels of torque densities and power densities that electric machines are now capable of, for example, beginning to compete with hydraulics in electro-mechanical actuation. Above all, I'm excited about contributing to the conversation of a rapidly changing electric machines industry. I want people to walk away from my seminar with renewed vigor for our industry knowing that innovation is vibrant in the electric machines world, and, hopefully, empowered with ideas for new growth."