It takes a few good motors to run a food plant. Mixers, conveyers and packaging equipment require a variety of motors for a variety of functions.

Interest in energy efficiency, which at one time would wax and wane with the fluctuations of the energy market, is now a permanent issue when considering motors. And while unsanitary design has never been welcomed on the processing floor, enclosed, encased, stainless and wash down-resistant are the buzz words for motors today.

"Since the Food Safety Modernization Act was passed last year, I would say the No. 1 concern is now hygiene — especially in direct food contact areas," says Kay Cabaniss, food and beverage industry manager at Baldor Motors (www.baldor.com), Fort Smith, Ark. "Food companies are looking more at stainless housings to eliminate rusting and chipping paint."

Indeed, all four industry sources contacted for this article mentioned that stainless motor housings were among the most important features for their food and beverage customers -- but efficiency was not far behind in the comments.

Most food plants are kept clean with regular wash downs that result in a continually moist environment. This means that everything in the room has to conform to that environment, and electric induction and servo motors are no exception.

"In food plants specifically, users are looking for more than just functionality," says Jim Gegg, global product manager, Rockwell Automation (www.rockwellautomation.com), Milwaukee.

"Because of the stringent cleanliness requirements, motors used in these types of conditions must be able to withstand frequent wash downs with high pressures and caustic chemicals."

Stainless steel housings, encapsulated windings and hygienic welds are among the features that help achieve hygiene standards. Rockwell also offers white paint on some of its products. "This allows food manufacturers to more easily see dirt while holding up to corrosive chemicals with a durable, two-part, white food-grade epoxy coating and corrosion-resistant stainless fasteners," Gegg says.

In 2010, SEW-Eurodrive Inc. rolled out a pair of stainless steel gear reducers designed to replace single worm gears. The stainless construction makes these ideal for food plants, but their technical design was aimed at the other big concern for plant operators — energy consumption. The company says the design of the helical and bevel helical gearing permits up to a 50 percent energy savings, plus the units run cooler than single worms.

Energy efficiency became not just a good idea but a mandate with the Dec. 19, 2010, final implementation of the 2007 Energy Independence and Security Act, which required more energy efficiency for industrial motors sold in the U.S.

"Because of the energy legislation, the U.S. government defined the most important feature [of a motor] as efficiency," says Tom Capell, marketing and training manager at SEW-Eurodrive Inc. (www.seweurodrive.com), Lyman, S.C.

SEW also introduced products with highly efficient drive systems built around permanent servo motors, high-efficiency gearing and electronic components with intelligent control modes. Others utilize no-contact energy transfer.

Whether using older or newer motor technologies, there is always a chance that energy will be wasted if systems are not properly sized or maintained.

"The efficiency shown on the nameplate is usually at 80 percent load, which is greater than the efficiency at 25 percent," says Capell. "Therefore, when the motor is oversized, the operating efficiency is much lower. It's important to size the motor to the load to get the most efficiency."

Baldor employs an energy-efficiency team that helps users track their energy consumption and meet goals for improvement.

"We calculate the energy savings per motor and the payback period for purchasing the energy efficient motors," says Cabaniss. "Our team has been in high demand this past year and we see this trend continuing into 2012. Baldor can identify energy saving potential in applications ranging from energy efficient motors to using variable frequency drives in pump and fan applications to high-efficiency gearing on conveyor applications."

Rockwell's Gegg also notes that electric cylinders, used in place of pneumatic cylinders for air compression, have enabled significant savings. Inefficient, leaky compression eats up thousands of dollars each year in a typical plant, he says.

Food manufacturers seek reliability at least as much as other manufacturers, Capell says, and when a motor fails, replacing it should be a quick, easy process. As packaging operations have become an integral part of food manufacturing, there is a trend toward the use of nimble, precise servo motors in the packaging room.

Servo motors utilize large powerful magnets and brushless technology to offer more power and torque and smoother, more precise movements than other types of motors. They also offer more predictable performance and better efficiency in a smaller foot print.

As more sophisticated primary and secondary packaging design has become standard in the food industry, servos have done well in this area well. They also increasingly are used in more sophisticated processing and filling equipment.

"Because of the cost of personnel and the demand of case-ready product, food processors have been dragged into the automation age, like it or not," says Capell. "Packaging has become a major part of a food processing facility. Therefore, there is more and more use of PLCs, servo motors and motion controllers. That places a higher demand on decentralized control and motors with integrated inverters right on the conduit box."

While standard induction motors come in a variety of sizes (from 1/12 hp to 300 hp and beyond), certain applications employ more specified equipment, such as vibratory motors.

"Vibratory motors have a variety of applications in food production," says Rob Beiersdorfer, senior account manager at Italvibras (www.italvibras), Princeton, Ill. "They are used mostly for conveying, compacting or separating."

The company offers various products that help food companies do things like sift foreign or unwanted materials from ingredients, and convey, separate or accumulate empty cups and bottles before filling.

What are the important considerations for food processors when buying vibratory motors? Stainless construction and energy efficiency, of course, Beirsdorfer says.