Growth and Investment in Solar Applications

Dunkermotor's Experience Key to Success in Alternative Energy Field

by Matthew Jaster, Associate Editor

solar power grid

There are a number of harsh environmental and mechanical conditions to address when supplying power transmission components to solar applications (photo courtesy of Neville Micallef).

In the solar tracker market, there are a number of harsh environmental and mechanical conditions to address in order to ensure low total cost of ownership over the desired system life. These include high wind loads, sand/salt/rain/ice, thermal expansion constraints, medium to high position accuracy and a high efficiency of operations. Because Dunkermotor has supplied the railway market for over three decades, the company has the engineering motor solutions to meet the demanding EN61373:1999 shock and vibration standard.

"The railway and agricultural markets provided an excellent background for working in harsh environments, which transferred very nicely to the solar industry," says John Morehead, vice president, business development at Dunkermotor USA. "As an example, we have over 30,000 motors successfully operating over 15 years in the New York City subway system."

Solar Components and Systems
Dunkermotor manufactures low voltage brushed and brushless DC motors, planetary and worm gear reducers, encoders and controls which have been used over the past two decades in a wide variety of applications in the solar industry, not only in photovoltaic (PV) trackers but also concentrating solar power (CSP): from parabolic trough and power towers to Fresnel and Stirling dish.

Dunkermotor brushless, DC motors

Dunkermotor's range of brushless, direct current motors offer long life, high efficiency and dynamic acceleration (courtesy of Dunkermotor USA).

"We produce motors to IP65 (total dust ingress protection and protected from low pressure water jets from any direction), IP67 (which goes further, being protected against immersion between 15 cm and 1 m depth). We also build IP69K products, which offer protection against steam jet cleaning. Our motor control boards are designed with up to 650,000 hour MTTF. Our motors for the solar market are designed to operate in temperatures from -40 degrees C to +85 degrees C and incorporate special venting devices to prevent condensation. In terms of our gearing, we employ proprietary lubrication techniques for the low speed, high torque and wide temperature ranges found in solar applications," Morehead adds.

By integrating the intelligent control as well as the fieldbus interface with the motors and gearmotors, a number of advantages can be gained, according to Morehead.

"Cables and wiring to discrete, separate control devices are eliminated, which is very important in solar applications which can span wide geographic areas. The embedded intelligence reduces bus traffic by running complex routines on board, such as homing, closing position loop with an integral absolute encoder or an inclinometer which can be linked by Modbus.

Further, intelligent motors can host and run program code to act independently when the network is down (and for example can return a tracker to a safe position), or run routines to lower bus traffic even further. The onboard control's integrated speed and torque regulation features prevent mechanical damage. Rather than requiring what was previously a purpose-built master control system, Dunkermotor's brushless STM solar tracker motors, with integral fieldbus, for example, can be controlled with any of a growing number of off-the-shelf PLCs which have a solar tracking function block built in. Such a simple, economic PLC is capable of controlling up to 127 STM motors over a 5,000 meter (16,400 feet) bus length using the motors' integral CANopen interface."

With fieldbus connectivity, scalability and immediate diagnostic capability, Dunkermotor embedded-intelligence solutions reduce cost of installation and ensure lowest total cost of ownership (TCO).

Dunkermotor components can be combined with control electronics, gearboxes and encoders

Dunkermotor components can be combined with control electronics, gearboxes and encoders in a module system to provide a flexible market solution (courtesy of Dunkermotor USA).

The Been There, Done That Approach
Although the U.S. solar market lags significantly behind Europe from an implementation standpoint, there's a continued push for additional alternative energy sources provided companies can squeeze through all the red tape. "The solar market is currently one of our most active application areas in North America, although it also is influenced dramatically by factors of a political and economic nature," Morehead says. "In essence, we've been spec'd into a lot of new systems that have not yet been green lighted."

For projects that actually get the go-ahead, companies may call upon Dunkermotor's customized solar experience for assistance. "We can help a design engineering team develop a system more rapidly based on proven designs which easily integrate with existing slew drives, pan and tilt mechanisms and the linear actuators used in the solar industry. Often, we can safely meet a customer's application requirement with a smaller lower energy consumption motor and gear assembly than they had originally planned," Morehead says "Our 'customized solution' approach is rather unique because we are able to use our large portfolio of configurable components (motors, controls, encoders, gearing, brakes) to put together truly custom solutions for each application. However, most of those solutions are made up of standard components that have the additional benefit of being more economic and available with shorter lead times," Morehead says.

Gearmotors Revisited
Though the solar market will play a large role in Dunkermotor's success in North America, the company is also focused on the factory automation and packaging machinery markets. "We are finding much interest in our embedded intelligence motor solutions, especially in light of the many benefits and advantages that the adoption of fieldbus networks can have in those markets," Morehead says.

The motor market, in general, is changing as consolidation continues in the gearmotor, electric motor and motion control industries and companies broaden their capabilities to meet the growing needs of OEM customers. "Our recent acquisition of the Copley Motion Systems linear motor business is an example of that and we continue to look at growth in North America as well through acquisition of complementary companies," Morehead says. "Fifteen years ago, a small, niche gearmotor company with a handful of OEM customers and annual sales of less than $5 million was a nice, promising business. Today, very few still exist that haven't been acquired or shut down. Because customers today want to look at their suppliers as sole-source solutions providers, it's no longer possible to stand still in this market. It takes continual growth and investment not just from a monetary, but also a technology standpoint."

The key will be getting the message across in North America that has been in Europe for decades. "I think Dunkermotor is the best kept secret in the American motion control market primarily because we had been focused on serving the U.S. operations of many of our European customers and a few OEMs in market segments like door automation where we are a world leader. Our objective is to let North American OEMs know that Dunkermotor has become more than a PMDC gearmotor company and that we have rapidly evolved in the motion control market," Morehead says. "With global operations in Europe, Asia and the United States, today we're a team of 1,000 that has produced more than three million motors for demanding OEM customers last year. We look forward to sharing that story with more American OEMs and building lasting relationships as we have in other markets."

For more information:
Dunkermotor USA Inc.
2511 Technology Drive Suite 105
Elgin, IL 60124
Phone: (224) 293-1300