Why Encapsulated Food-Safe Motors
Engineering to the highest possible standards of protection
Regal Beloit Corporation, a leading manufacturer of electric motors, electrical motion controls, power generation and power transmission components, announced that the Extreme Duck Ultra motor came onto food and beverage processing lines following two decades of the Duck product line development to drive the most intense wash-down and sterilization spray applications in the industry. The company’s top-of-the-line Extreme Duck Ultra motor established a large installed base in the food and beverage industry for one key attribute: increased durability in food and beverage related conditions.
Every aspect of wash-down spraying — the splash-back of scalding hot water, corrosive saltwater, acids and solvents, all pumped at high pressures in often high humidity or dusty environments — seems custom designed to destroy motors. And they did. The primary advantage of the Extreme Duck Ultra motor was that it prolonged the inevitable.
The original Washguard® (or White Duck) motor in the early 1990s was one of the first motors specifically designed for high-intensity, wash-down applications. A steel housing, precisely welded seams, tight seals and sealing washers all helped prevent water and small particles from infiltrating the motor and causing it damage and failures. At the time, no motor came close to completely blocking humidity, vapor, water spray, corrosives and the finest dust particles, but the White Duck motor came as close as technically possible. That made it the motor of choice for food-grade and pharmaceutical spray-down applications: work that required completely clean and sterile equipment. Still, even the White Duck motor was vulnerable to splash-back,harsh wash-down conditions and quicker endoflifein the field; thus, it was not invulnerable.
In 2004, the National Electrical Manufacturers Association (NEMA)adopted the International Elecrotechnical Commission (IEC) standards and test procedures to determine “ingress protection” in enclosures, i.e., the “IP rating”. This rating, now universally recognized in multiple industries, consists of the letters IP followed by two numbers; these define the amount of protection the device has against foreign matter which could get inside its system and cause it to fail. The first number (0–6) indicates its protection factor against solids, such as dust. The second number represents its protection factor against liquids. Initially,the second number ranged from 0–6, but eventually that changed to 0–8 as new standards were established to enable manufacturers to prove a higher level of impermeability under even more demanding conditions. Then, in 2013, the IP69k rating established the ultimate ingress protection for the most extreme applications.
With the new IP standards in place, third party testing was conducted to rate the Extreme Duck Ultra motor. That motor was rated IP66: dust-tight and protected against powerful jets of water. The motor was safe from the intense water spray it helped generate and suitable for most applications. But in other applications, the Extreme Duck Ultramotor faced far harsher conditions than just high-pressure water. The engineers believed they had to achieve better than an IP66 rating and build a motor that would stand up to the worst —and work reliably and continuously in any application.
The Extreme Duck Ultra motor’s primary application has been in the food and beverage industry. The Food and Drug Administration (FDA) has stringent standards for wash-down and equipment sanitation in all aspects of food production. For example, in defeathering and descaling systems, poultry moves through high-pressure spray sand steam in every direction for 30–75 seconds at water temperatures of up to 180°F (82°C), with motors exposed to the hot, intense backsplash continually, while other wash-down systems continuously clean and sterilize every exposed surface in the processing plant. The wash-down and sterilization of equipment and containers often require adding chemicals such as citric acid, chlorine and even diluted hydrochloric acid to the high-temperature spray, adding to its corrosive nature, as does the saltwater used in seafood processing plant wash-downs. Water and beverage companies require intense wash-downs at their bottle transfer lines; breweries need wash-downs after every step for every batch produced.
The applications for wash-down motors go beyond the food and beverage industry. Pharmaceutical manufacturing equipment and conveyors require complete cleanliness and sterility for product quality and to prevent cross-contamination. The motors propel machine-cutting fluids and water-cooling systems in a range of industries —even simulating rain and saltwater spray in automotive test tunnels. To handle all these applications and survive, the Extreme Duck Ultra motor would not only be exposed to the hottest water, highest humidity, corrosive elements, and dirt anddust full-time without failure, but it would also have to perform in any mounting position while supporting inverter-driven, variable-speed applications.
This would require a higher level of engineering, one focused on attaining near-absolute ingress protection. The goal was the IP69k rating: as close to total imperviousness as the IP standard could measure.
Regal engineers set out to completely redesign the top-of-the-line Extreme Duck Ultra motor, designing motors from ½ to 2 HP in most standard frames, and added two larger motor designs capable ofup to 10 HP in new, larger frames for heavier-duty applications.
The first design decision was an all stainless-steel housing, which provides far higher corrosion resistance than even carbon steel with composite coatings, and provides tight, precise welds: the first line of defense. Stainless steel also allowed a full-fact nameplate to be permanently etched onto the motor frame.
Then the engineers addressed their primary challenge: sealing, particularly around the rotating shafts. Instead of multiple seals, a new, two-piece shaft seal with a flinger provided three points of protection from water, oil and chemicals, and ensured the motor could be installed in any orientation. This proprietary seal shaft was considered so critical that it underwent a year oftesting — 8,760 hours — before the system was released for third party IP evaluation.
The conduit had always been the most vulnerable area for intrusion. In the new Extreme Duck Ultra motor, a welded pipe nipple at the ingress eliminated the need for an O-ring at the conduit, which often deteriorated and allowed fluid intrusion. At the conduit itself, engineers eliminated the most common field failure: lead wire wicking. In previous models, the motor came with a kit of connectors with heat-activated adhesives an end user could install to water-proof the lead wire, but many installations did not allow the use of heat guns to apply the adhesives, so the lead wire was often insufficiently protected. The engineers replaced this with non-wicking leads directlyin the motor. The result was a complete, non-wicking power supply, using a specialized seal and wiring fully encapsulated in epoxy, all color-coded for easy installation. The conduit box itself, also stainless steel, rotated 360 degrees for convenient wire placement.
Then, the entire body assembly, including the end bells, was fully encapsulated with a proprietary epoxy using a vacuum assist, blocking virtually all air pockets where condensation could occur —and eliminating the need for drain plugs and breathers on the motor. Once enclosed, the completely impervious windings incorporated an easily handled Q-Car™ rotor cartridge. The result? Potentially, an FDA-approved, food-grade, wash-down motor which is completely impenetrable to liquids, chemicals and dust in any mounting position in any application. Only testing would tell
Independent testing to earn an IP rating is rigorous and tightly specified, including the test equipment used and particles and fluids tested. As noted, the rating consists of two numbers: protection against solids and protection against fluids.The goal forthe motor was the highest possible rating: IP69k. This rating establishes complete protection against any ingress of dust or high-temperature and high-pressure water. This certification would establish the Extreme Duck Ultra motor as ideal for conditions where equipment must be carefully sanitized, must withstand rigorous wash-down procedures, and, in many industries with dust and dirt issues, it ensures that dust cannot penetrate the motor and cause it to fail.
Previous Extreme Duck Ultra motor models passed dust resistance testing with perfect “6” ratings —dust-tight —and the new models were no different. Seams were tested with a 1 mm wire test probe, and then the motor was placed in a cabinet test chamber filled with blowing talcum powder or alum dust (particles as small as 0.5 microns). The motor was subjected to a vacuum of up to 20 mbar for up to eight hours while inside the test chamber. Upon disassembly, no evidence of dust ingress was found in the motor: it was dust-tight—a“six”.
For fluid protection testing, the motors were placed on turntables at 4–6 RPM. They were then continuously sprayed with scalding water of a temperature of 176°F (80°C) at a pressure of 1,160–1,450 PSI for a minimum of three minutes —from just 4–6 inches away —until the entire surface of the motor had been sprayed.
The motors were fully disassembled and examined for any evidence of fluid penetration or residual moisture from steam. None was found, and the Extreme Duck® Ultra motors were certified IP69k.
Today, testing continues on every Extreme Duck Ultra motor produced: each is completely pressure-tested before leaving the plant to ensure the motor is completely sealed. The international IP69k standard asks (and answers) the question: “What is truly water-proofand dust-proof?” The Leeson® Extreme Duck Ultra motor proves the value of a truly water-proofand dust-proof motor:
- Pressure testing guarantees liquids don’t penetrate the motor, increasing motorlife and reducing plant downtime
- Eliminating corrosion ensures longer motor life and reduces operating costs
- Protected wash-down motor enhances reliability, flexibility and durability, decreasing operating expenses while increasing uptime
- Motor redesigns increase energy efficiency: the Extreme Duck Ultra motor meets the Department of Energy (DOE) Energy Security Act Mandate to meet NEMA Premium® Efficiency levels
The Leeson Extreme Duck Ultra motor won the 2015 Plant Engineering Product of the Year award and the 2016 Control Engineering Engineer’s Choice Award in both sponsor’s motor categories.