Stainless steel motors come of age

The UK’s pharmaceutical manufacturing sector has traditionally 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 Rob Wood, UK Sales Manager at ABB Limited

Pharmaceutical production is governed by stringent legislation that stipulates world-class manufacturing techniques to ensure that patients get their medicines safely and efficiently. Critical to any process are stringent levels of hygiene and sanitation that avoid contamination and cross-contamination.

To achieve these standards, the traditional approach taken by pharmaceutical manufacturers is to do a complete washdown of their manufacturing facility.

However, this is not as simple or straightforward as it sounds. The electrical motors that power many essential manufacturing processes 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 and, in the worst-case scenario, failure to supply.

To make their motors last longer, many facilities cover them with shrouds. Whereas shrouds do protect motors on equipment in washdown areas, they create gaps and dead spaces where product ingredients or cleaning compounds can build up, compromising product efficacy or allowing bacteria to breed.

In many cases, the motor is fan-cooled and acts as a powerful vacuum cleaner, sucking 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.

Rob Wood

An alternative is to use a stainless steel motor that can withstand washdown conditions without needing protective shrouds. These motors are already widely used in North America. However, their take up in Europe has been relatively slow, with machinery suppliers still preferring to supply standard motors.

Unless a pharmaceutical manufacturer specifies stainless steel, then standard motors are fitted because they are more affordable. Some European machinery suppliers even fit standard 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 pharmaceutical manufacturers.

In fact, in extreme, conditions, these motors save money on maintenance, lost production owing 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 the three main characteristics to look for to ensure you are getting the best motor for your application.

Hygienic design: stainless steel motors for pharmaceutical production 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 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.

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.

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, 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.

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