May 2019

37 www.drivesncontrols.com May 2019 MOTORS SUPPLEMENT n Stainless-steel motors come of age P lants that process meat, poultry, dairy and other high-risk products need to keep their hygiene areas sanitised. With food safety at the heart of every food and beverage company, undertaking a complete washdown of the facility demands products that are corrosion- free and which do not harbour bacteria. However, general-purpose motors cannot withstand strong chemicals and high- pressure washing because their paint flakes off, leading to corrosion. Water can get inside and cause the motors to fail. Any failures mean expensive downtime. To make their motors last longer, many plants cover them with shrouds. While shrouds do protect motors on equipment in washdown areas, they create gaps and dead spaces where food particles can build up, allowing bacteria to breed. In many cases, the motor is fan-cooled and acts like a powerful vacuum cleaner, sucking air and airborne contaminants into the shroud. There is no easy way to access the motor inside the shroud, and the only way to ensure that everything is completely clean is to remove the shroud – a time- consuming operation. An alternative is to use a stainless-steel motor which can withstand washdown conditions without needing protective shrouds. These motors are already widely used in North America. In fact, in some applications in the US food industry, stainless-steel motors are the only acceptable technology. However, their take- up in Europe has been relatively slow, with machinery suppliers still preferring to supply standard motors. Unless a food producer specifies stainless-steel, regular motors are fitted because they are more affordable. Some European machinery suppliers even fit regular motors and shrouds on equipment for their home market, but use stainless-steel motors in products that they export to the US. However, the situation is now starting to change. The people who have to operate, maintain and, above all, clean the equipment, know only too well that shrouds have no place on machinery that has to be washed down regularly. Stainless-steel motors simply make life much easier for food producers. In fact, in extreme conditions, these motors save money on maintenance, lost production due to downtime, and the cost of replacing them. So, for those who have seen the light and are keen to reap the benefits from stainless- steel, here are four characteristics to look for to ensure you are getting the best motors for your application. n Design to hygienic principles Stainless- steel motors for wet-food processes must be able to withstand harsh washdown conditions and high humidity. Ideally, they should be compatible with clean-in-place (CIP) methods to reduce cleaning times. Look for motors with a smooth, self-draining housing with no cavities where food particles could collect. Any markings should be laser etched onto the frame, avoiding channels and ridges where contaminants could accumulate. A typical stainless-steel motor can last up to five times longer than a standard motor in hard washdown environments. n IP69 ingress protection The level of ingress protection is important. Many motors advertised as being suitable for washdown offer IP66 protection, but IP69 – which provides protection against powerful, high- temperature water jets – is superior and essential for effective sealing. n Food-grade lubricants H1-rated lubricants suitable for food environments should be used in the bearings to avoid potential contamination and to maximise food safety. n Encapsulated windings For improved reliability, the motor should have encapsulated windings. This ensures a longer lifetime in humid conditions and helps to reduce the total cost of ownership. In summary then, stainless-steel motors can be cleaned in place, help to reduce water consumption and save time, making them the ultimate in reliability for hygiene areas. n Stainless-steel motors offer many advantages over shrouded machines in food and beverage applications, but at a higher initial cost For many years, the UK’s food and beverage sector has preferred to use shrouded motors, rather than the more costly stainless- steel alternative. But advances in motor technology are making the latter more attractive, argues ABB’s Luciano Santos.