Servo motor technology meets today's automation challenges

Anderson worked for several motor companies in the Midwest before deciding to start his own company. He founded Custom Servo Motors seven years ago, and sold the company to MTS System Corp. more than five years ago, though he still is involved in the day-to-day operations of the company. Recently, Custom Servo Motors bought Bregenhorn-Butoew, a custom power amplifier manufacturer in Germany, and Performance Controls, a custom power electronics company in Horsham, PA. Today all three groups are strategically aligned under MTS Automation.

Now that the price has gone down and the technology is easier to use, education is the major obstacle to growth in servo technology, Anderson says. "Manufacturers like ourselves need to show engineers the tangible benefits of using the technology."

Design News: In industry in general, many manufacturers talk about being custom suppliers. What does custom mean in the high-end servo market?

Anderson: It means giving the customer what he wants. But, that doesn't mean that the product is a special. In our case, we have a modular approach--tell us your application and what performance you want and we will assemble a motor to meet, or exceed the performance requirements. Seventy percent of our custom orders are for a configuration of our standard product line. Customers can actually design a motor from our sales literature.

Q: What are the major applications in the high-end servo market?

A: High end to us means high peak torque, high acceleration, the smallest physical package possible. The major applications are press feeds, because of their high speed and hard stops; packaging equipment, where repetitive acceleration and deceleration are important; and factory automation, where speed of move is important.

Q: What are the major benefits of servo technology?

A: Flexibility in machine tool operations is one of the biggest benefits. Additionally, servos replace traditional gears, belts, and pulleys, thus eliminating the problems of wear and failure typical with those older technologies. Servos increase productivity, reliability, and machine throughput.

Q: What is the major obstacle to growth in servo technology?

A: More education on how to use servo technology. Manufacturers like ourselves need to show engineers the tangible benefits of using the technology. There has been a lot of education in the last five or ten years. Potential users are now aware of the benefits and value of servo technology. Another obstacle seems to be cost effectiveness. That is, the actual cost of the servo hardware compared to alternate technology. Five years ago, 50 inch/lb servo drives might cost $2,400 per system. Today, the price is about 1/2 that or $1,200. Servos are almost at the price threshold of stepper motors now. The price has gone down because the servos are easier to implement and use and require less support.

Q: What is the main reason for their use ?

A: Competitiveness in the marketplace has customers demanding higher performance and productivity rates which servo technology provides.

Q: Where is servo technology headed?

A: Higher power ranges. Traditionally, there have been two solutions--electrical and hydraulic. The electrical solution utilizes dc brush motors or ac induction motors which have always carried very high motor inertia. Typical hydraulic solutions have been replaced by high-power servo applications, including tube benders, winding equipment, and various press applications, eliminating the necessary hardware and maintenance associated with pumps, cylinders, fluids, etc. Today, 400 inch/lb servomotors are common. One example is the replacement of a 200 hp brush-type motor with a 75 hp servo motor, which increases machine performance and reduces motor inertia. Servos have actually increased product throughput in all the above cases.

Q: What areas of the world hold the most promise for proliferation of servo technology?

A: North America is, of course, the biggest market. But, 30% of our sales are outside of North America. In the next five years, North America will represent less than 50% of our sales. South America could outpace Asia.

Q: What will limit the growth of your company?

A: People--In a very tight labor market, it is very difficult to find talented people. We look for hands-on people who can comfortably interact with others. It's important to have common sense. You don't necessarily have to be the smartest guy in the class, but you have to be able to communicate. It's hard to find people with technical know-how and the ability to communicate. We hire engineers from outside our own field and train them. We also expect our engineers to talk to customers. That's one way they learn to understand customer problems.