August 17, 1998 Design News
Exclusive interviews with technology leaders
Servo motor technology meets today's
Custom Servo Motors, Inc. New Ulm, MN
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
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
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
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.†