The Times, They Are Changing

The Times, They Are Changing

Occasionally in conversation you make a reference to technology and then realize that you are old. I could talk about the first microprocessors, vacuum tubes and the first power MOSFETs, but I will not bore you with these stories.

But I do notice continued changes in our industry and it often takes time and inertia for some of these trends to happen; but when they do, they are very powerful.  Looking at some of our recent projects, I noticed that one trend that has often been touted by some manufacturers is spreading ever more rapidly, i.e. — the integrated motor.

In reality, many technical obstacles remain that prevent the proliferation of integrated motors, but we are certainly seeing an ever increasing number of these motors enter the marketplace.

It is easy to see the appeal. Envision a conveyor system for a moment where multiple motors must be connected and synchronized. We can make very small and reliable electronic controls these days, and a conveyor system with small, integrated motors requires a power connection and a communication link. This can be as simple as a Wi-Fi signal, a powerline carrier, an Ethernet — or any other robust and simple communication technology. Thus, with a power connection and communications, your system is ready to run.

Compare that to a traditional system where we have to mount drives, connect motor leads and feedback devices, and it is easy to see the advantages of integrated motors. And by the time you factor in the installation costs and the improved reliability — due to the reduced wire interconnects — then the integrated motor will, most likely, be the more cost-effective, although less familiar, technology.

The main drawbacks of the integrated motor are size and thermal management. Today the drive electronics can be made to fit a very small volume.  But the integrated motor will still command some added volume, although as drives become smaller the added volume will be shrinking.

The next challenge is the thermal management of the motor. We need to keep the internal temperatures of the motor low enough to ensure a long operating life of the control electronics. In most instances that will not be a challenge, but if we look at under-the-hood applications, then this may well prohibit the use of an integrated motor.

For the motor design, high temperatures are becoming less of an issue. High-temperature magnets, ceramic wire or reluctance-type motors allow us to build cost-effective, high- temperature motors. We just completed a design for a 450º C (840º F) motor, and yes — I have finally worked with the much talked about carbon nanotube wire. We in fact now have a sample in our lab, and the prospects are very exciting. But that is a topic for another day.

The control electronics, however, are still very limited and most components are limited to 125º C (255º F) maximum operating temperature, while some power devices are rated up to 175º C (345º F) max. The technologies to go to higher operating temperatures are currently emerging for military application, but once the technology has been fully developed, industrial applications are not too far behind.

The next frontier is using 3-D printing to build production motors and also for printing electronic packages. A 3-D-printed package can perform multiple functions. First, it can be made to seal and protect the electronics from the environment. A custom-printed packaging solution can mix materials to design and create a package that is strong, thermally conductive and also shielded for EMI protection (3-D printers allow printing metal for electrical connections and shielding). Lastly, we have great flexibility to shape this package, so it can be a seal, an end-bell, and also have mounting provisions and integral connectors — all of which can potentially make 3-D-printed packages economically attractive.

Of course, there is nothing that says we cannot use the same technology to package conventional controllers.

I remember seeing my first 3-D-printed motor housing in the year 2000. And now printing has become an established technology where even a small company, like ours, can own and use. In fact, we have saved a lot of money by printing prototype parts versus getting them from a machine shop; but we are not yet doing any volume production using 3-D printing.

And I am hoping to see the day when I can look back and say — “I remember when they started 3-D printing in motor manufacturing. That was so long ago and now we print the whole motor. Back then we never thought we would — or could.”

But the times are changing.


About Author

George Holling

With over 70 publications and 9 U.S. patents on sensorless and efficient motor controls and low-cost power circuits to his credit, George Holling (PI) is an in-demand consultant to many major U.S. and International corporations for motors and drives. At present he holds significant influence in two companies — as technical director of Electric Drivetrain Technologies (2011– present) Moab, UT and as CTO of Rocky Mountain Technologies (2001– present), Basin, MT. Holling is a graduate of the University of Aachen, earning his B.S. (1974), M.S. (1978) and Ph.D. degrees there, while picking up his MBA here at the University of Wisconsin. His career has spanned both the commercial and academic arenas, the latter including stops at (Dean, Computer Science & Engineering) Utah Valley University, 2001 – 2003; and (Adjunct Professor), Western Michigan University, 1997 – 2002. From the commercial side, apart from his current positions, Holling has served as Project Engineer and Product Line Manager, UNICO; Franksville, WI (1978-1981); Project Engineer, General Electric, Medical Products Division, Milwaukee, WI (1981-1983; Manager R&D, Pacific Scientific/Honeywell Motor Products, Rockford, IL (1983-1985); Vice President of Engineering, Regdon Solenoid, Brookfield, IL (1988-1990); President, Advanced Motor Controls, Sun Prairie, WI (1990 – 1999); and Vice President of Engineering, Cordin Company, Salt Lake City, UT (1999 – 2000). Holling has also spearheaded projects for the development of high-efficiency motors and drives up to 400 kW, and has successfully negotiated licensing agreements with U.S., Chinese, Japanese and Indian customers for the licensing of motor and drive technology.

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