In 1987, Processing began publication in Chicago. Since then, its editors have witnessed changes in regulations and standards and in the equipment that operates industrial processes. Innovation has occurred throughout the process plant. However, no equipment has been scrutinized more than motors, and no equipment has helped improve control and efficiency more than variable frequency drives (VFDs). In this piece, motor and drive experts from Nidec, Siemens and TECO-Westinghouse Motor Company (TWMC) share their insights into the drive and motor innovations of the last 30 years and what improvements and trends we can expect during the next 30.
Top motor innovations
During the last three decades, motors have evolved, with smaller footprints, standardized production and increased energy efficiency. According to Ryan Maynus, application engineer for Siemens, the use of better processing tools allows manufacturers to "more accurately predict motor performance and reduce waste in the product. [Using] better processing tools, like more powerful computers, Siemens has been able to more accurately predict motor performance. This change allowed for a more standardized product while reducing waste in the motor."
The footprint that modern motors require have decreased and improved.
Motor innovations like efficiency advancements, spurred by the National Electrical Motor Association (NEMA) and the U.S. Department of Energy (DOE), were cited as major innovations by Tim Albers, director of marketing and product management at Nidec Motor Corporation.
"From small, single-phase up to larger, integralhorsepower, three-phase motors, the industry has dramatically changed to raise the basic efficiencies on most standard induction motors," Albers said. "Thirty years ago, motor efficiency standards were just being created along with accepted test standards. Now they are embedded into the fabric of the industry."
Because of the DOE motor rule, end users purchasing new motors from 1 to 500 horsepower hp) must purchase NEMA Premium Efficient motors (eia.gov).
"Although energy costs have really impacted the need to develop more efficient induction motors, the DOE motor efficiency rules have influenced the industry as well. In general, there is an increased focus on system efficiency," Maynus said.
Other motor innovations that Maynus cited are improvements in airflow analysis and the development of a rigid shaft motor at a two-pole speed.
"One of the challenges with operating a larger hp motor at 3,600 rpm or at a speed range with a VFD is being able to meet the vibration requirements. By introducing a rigid shaft motor that can achieve power ratings up to 8,000 hp, [the user] maintains the benefit of an optimized power train system at a more affordable life-cycle cost," he said.
Michael Prater, director of sales and marketing for TWMC, indicated that the first TWMC innovative product was manufactured a little more than 30 years ago in 1985.
"The World Series motor product line was … innovative for its time. Large motors back then were operating at efficiencies in the 80 percent range, and the World Series took those levels to the 90 percent range," Prater said.
Albers also indicated that one of the top motor innovations was the integration of VFDs with motors and controls in process applications, which leads the conversation to the top innovations in drives during the last 30 years.
The experts’ top motor innovations
- Increased efficiency of induction motors
- Standardized products
- Inverter wire standard in integral-horsepower, random-wound motors
- Optimized two-pole design to meet noise and vibration requirements
- The growth and penetration of brushless permanent magnet motors
- Improved airflow concepts, along with optimized flux paths, to increase power outputs by up to 40 percent in the same frame
- Rigid shaft motor at two-pole speed
- A product line to allow up to 6,000-rpm operation without using exotic components
Top drive innovations
As difficult as this fact may be to believe, VFDs applied to processing systems is a relatively new phenomenon. Albers and Mark W. Harshman, director of technical business development at Siemens, agree that the move from Darlington Power transistors to using IGBTs was a leap in VFD development.
Harshman said, "In 1994, the first successful cascaded H-bridge VFD was designed using IGBT devices. The Robicon Perfect Harmony was a … design that provided harmonic free waveforms to the … plant power grid and [the] output voltage waveform that could be used by existing motors, no matter what their age. This breakthrough resulted in the establishment of the cascaded H-bridge design as the industry standard, which became the most [duplicated] design with the largest installed base of any VFD topology."
Prater said that VFDs "allowed for overall system efficiency improvement. Adding a VFD to the system also corrects power factors which could lead to lower energy costs for the plant."
Smaller VFDs are also becoming a requirement in many industries. In response to the DOE rules and grant funding, many end users "are already demanding increased efficiency and smaller footprint," Prater said. "In the coming years, we can expect that footprint to continue to shrink while the efficiency increases. Customer specifications already reflect these concerns and requirements. The customer processes now are built around VFDs [because the] industry has accepted them as a valid process control method that saves cost."
The next 30 years
We asked our experts to look into their crystal balls and tell us what innovations and trends they expect to see during the next 30 years. Not surprising, the Industrial Internet of Things (IIoT) was an important factor on many of their lists.
Albers expects to see "more and more connected points.” He said, “We will have the ability to see and evaluate pretty much every process as well as the operational health and capability of the equipment. Call it what you want — IIoT, Internet of Things, Industry 4.0 or Connected Factories — we will move beyond monitoring and controlling the process, to predicting process outcomes and predicting and scheduling equipment maintenance and repairs as opposed to reacting."
This monitoring trend is also on Harshman’s list. "Online diagnostics and monitoring, available 24/7 via iPhone and iPad will be the norm, and customers will expect to be notified by the motor or drive well before a failure occurs," he said. "The online capability may even include dispatching a service technician or sending replacement parts before the VFD or motor has failed."
The experts’ top drive innovations
- The introduction of new power semiconductor devices, which allowed for the development of larger, medium-voltage VFDs
- The addition of standard communications protocols and basic processing as a standard part of a VFD
- Change from Darlington Power transistors with switching frequencies around 800 to 1,200 hertz to using IGBTs with a range of 2 to 20 kilohertz
- The introduction of the first cell-based VFD
- Fast processing to allow for vector control of speed and torque throughout a wide range
- The ability to control an induction motor and synchronous reluctance of a brushless permanent magnet motor all with one set of hardware and only requiring software updates of configuration settings
Combining a motor with a VFD has already begun. Harshman predicts this trend will grow in the future.
"Recently the DOE has begun funding on variable speed motors that combine the motor and drive into one package where the drive is integral to the motor," he said.
"This is aimed at reducing the footprint by 50 percent and decreasing costs … By 2030, VFD manufacturers still manufacturing stand-alone VFDs in cabinets may be competing with a single variable speed motor, especially in the power ranges below 1.5 megawatts."
Increased efficiency seems to be the message from all the experts. "We’ll definitely see a continuation of constant energy efficiency," said Prater. “We already see that the DOE is pushing from premium efficiency (IE3) to super premium efficiency (IE4). I guess we’ll stop short of 100 percent efficiency, since that’s impossible, but we’ll keep looking for innovations to make it possible."
As the process industries continue to push small footprints, better efficiency and faster processing, the industry will put forth more drive and motor innovations to answer end-user demand.
Editor’s note: Email us at [email protected] and tell us your top motor and drive innovations.
To read the full Q&A from our experts, visit www.processingmagazine.com/motors-drives-30th-anniversary-qa.
Lori Ditoro is editor in chief of Processing. She may be reached at [email protected].