ABB Food safe motors feature a stainless steel housing to resist corrosion, and IP69 ingress protection to ensure that high-temperature, high-pressure spraying will not cause damage. They are also easy to clean, with a smooth, self-draining outer surface that has no angles where contaminants could gather.
“Our Food Safe motors are already in use at a number of customers’ plants,” says Tero Helpio, Global Product Manager, IEC Food safe motors, ABB. “In order to prove their long-term performance under realistic washdown conditions, we worked with a state-of-the-art laboratory in Västerås, Sweden to devise a set of tests replicating industrial-type sanitizing procedures.”
Food safe motors unaffected by washdown
“We put two IEC stainless steel Food safe motors through the tests and they performed extremely well. They were largely unaffected and were still in full working order at the end of the test program. In particular, no water, condensation or indication of corrosion was found inside the motors. All the three main O-rings and drain plugs remained tight.”
“For comparison purposes we also tested a standard painted aluminum motor. This motor started to deteriorate very quickly. The paint on the housing blistered and flaked off, and the shaft and other steel components suffered severe corrosion. Washdown chemicals penetrated both the terminal box and the main housing, causing short circuits between the phases and ground. The aluminum rating plate became detached from the motor. This standard motor failed well before the end of the tests.”
Realistic clean-in-place cycles
The test regime was designed to reproduce typical CIP (clean-in-place) cycles in the food and beverage industry. Three different chemicals commonly used in poultry and other plants were used: a strong alkaline detergent, a strong acidic solution and a sanitizer. The concentrations, temperatures and contact times were based on those used in industry, with pH values measured and readjusted every 2-3 days during the tests.
A seven-stage test cycle was prepared to represent a full week of daily washdown sequences. Detergent and sanitizer were applied during every stage, with acid applied once per cycle. This reflects the common industrial practice of washing down with acid once each week. Temperatures up to 55 oC and pressures up to 25 bar were used. In all, a total of 158 cycles were performed, corresponding to 1,106 daily washdowns or 418 total hours of testing.
Electrical tests and visual inspections were done at regular intervals. At the end of the test period all three motors were opened up to enable internal inspection.
IP69 ingress protection keeps liquids out
One observation from the tests underlines the importance of ensuring that all components exposed to washdown conditions have IP69 protection. The two stainless steel motors were identical except for the cable gland: one was fitted with a polymer gland, the other with an IP69 stainless steel gland. During testing the polymer gland developed a small fissure in the nut. This did not result in any leakage of liquids into the terminal box in this case, but it clearly shows that IP69 ingress protection is the preferred option for washdown areas.
Standard motors unsuitable for washdown
The tests also confirmed that standard motors – like the painted aluminum motor – cannot withstand clean-in-place conditions.
“Paint flakes, rust, and particles from the rating plate could contaminate food products, leading to an expensive recall,” Helpio explains. “Some plants try to get around these problems by protecting their standard motors with shrouds, but the shrouds actually cause new issues. Food particles can collect inside the shroud, hidden from view, providing the potential for bacteria to grow.”
Food safe motors with their stainless steel housings and laser engraved rating plates avoid all the problems associated with standard motors. They eliminate the need for motor shrouds, providing 360-degree access for inspection and sanitization, and the easy-to-clean surfaces mean that less water and chemicals are needed. The tests prove that Food safe motors successfully withstand washdown conditions, giving plant operators confidence that they will help to reduce unscheduled downtime.
