IMAGE 1: Washdown procedure (Images courtesy of Meg-Alert, Inc.)
Continuous offline I/R testing can help combat motor failures.

The food and beverage industry battles with unexpected electrical equipment failures on a daily basis, mostly due to the necessary washdown process that is required under Occupational Safety and Health Administration (OSHA) and Food and Drug Administration (FDA) regulations. Food processing equipment can get dirty during production, and even the tiniest splatter of ingredients can leave a biofilm that attracts pathogens. Greasy films can also form on surfaces, potentially causing falls and making it dangerous to work in the area.

The root of the problem is all food and beverage processing areas require absolute cleanliness. This means a continual cleaning regimen that includes high pressure steam and hot water coupled with industrial strength detergents. Machines on the production floor that are too large to move need to have washdown performed in place. Despite their best efforts, cleaning crews sometimes expose the motors and electrical junction boxes on the processing equipment to the steam and water, making it virtually impossible to keep moisture out of the electrical components and motors.

6 Basic Stages of Washdown Procedure

Prewash: A prewash to remove caked-on grime will prepare the surface for sanitation. The prewash should remove all visible soiling from the machine, leaving only thin biofilms that can be broken down by detergent in the next step.

Soak: Next, the machinery is sprayed from top to bottom with a foaming detergent, coating every surface in a solution that will dissolve oil and sugar residues.

Scrub: Mechanical action is necessary to ensure the removal of all traces of organic matter. Soft-bristled brushes are gentle on equipment and can squeeze into tight corners, but stiffer brushes may do a better job of removing stubborn materials.

Sanitize: The cleaned surface is now ready for a sanitizing agent, which will kill any lingering pathogens. Many quaternary ammonium compounds (quat)-based sanitizers are designed to be no-rinse and can be left to dry on the equipment.

Dry: Pockets of moisture are not compatible with a sanitary environment. Bacteria thrive in puddles and pools, so the washdown should conclude with the equipment in a fully dried state.

Verify: Finally, verify the washdown has successfully removed all traces of food residue. Whenever possible, visual inspection should be complemented with an adenosine triphosphate (ATP) laboratory test, which will verify no organic material remains on the machine’s surface.

At a chicken processing plant in Westfield, Wisconsin, motors and junction boxes were found to be the weakest link in their processing operations. Water is a conductor of electricity, so a damp motor is an accident waiting to happen. The motor does not even need to be wet, as high humidity alone can be enough to cause a catastrophic failure. Likewise, motor failures have also been caused by food dust, dirt and contaminants that cause overheating of the electrical insulation, which leads to shortened insulation life.  In the best case scenario, a damp motor will blow a breaker. More often, the motor instantly shorts out and destroys the windings. In the worst case scenario, a burned-out motor also destroys the motor-starting circuitry, the cabling and even the attached machinery. In environments with flammable or combustible materials, these ground faults have been the cause of fires, explosions, injuries to workers and even deaths.

In the case of the chicken processing lines, the damp motors that resulted from the daily cleaning of the lines were failing on a regular basis. A processing line with multiple motors is dependent on every motor operating trouble free. When a single motor failed, the entire processing operation on that line was shut down. With these shutdowns came the problem of hundreds of pounds of chicken frozen in various stages of processing having to be discarded.

The Cost of Motor Failure

The plant quickly learned a simple motor failure cost far more than the cost of just a replacement motor. There is always a labor cost to removing and replacing a motor, but the greater costs are associated with the downtime that results from the interruption of a high-volume process. Here are just a few of the other costs the plant faced with motor failure:

  • lost labor costs for workers idled by the breakdown
  • lost product costs for the chicken (in various stages of processing) that was no longer saleable
  • cleanup and disposal costs for ruined chicken resulting from the shutdown
  • expensive emergency rewind repair costs versus recondition costs
  • missed deadlines for orders, delayed shipments and destroyed timetables for the delivery trucking fleet
  • potentially damaged relationships with users that were affected, as well as the loss of reputation for reliability in the industry

To try and combat these problems, the plant began an extensive new preventive maintenance program. Every Saturday (normally not a production time), every motor on every processing line was manually insulation resistance (I/R) tested with a hand meg-ohm meter. The volume of motors necessitated a team of electricians to do the testing, and even then, many motors were skipped in the process.  The intended result was the elimination of motor failures.

The high cost of this labor-intensive effort could have been justified if it had accomplished its goal, but the results were less than impressive. The motor failures, although lessened, still continued. The plant electrical engineer soon realized the manual testing was not going to stop the motor failures on startup. After researching the technology, they purchased permanently installed automatic I/R testing systems for each freezer line, which reduced frequent motor failures dramatically and eliminated the manual testing program. The results were immediate labor hour and repair cost savings.

A major snack food company located in Charlotte, North Carolina, was having the same type of issues with its critical motors at its plants. Food dust and moisture from the washdown procedures were causing unplanned outages and costly motor rewind repairs. To keep up with the highly competitive snack food market, the plant reliability engineer went looking for a way to prevent the motor failures on startup in order to improve the reliability of
operations as well as safety at the plant. They found a company in Wisconsin that manufactures automatic insulation tester and monitoring systems. These systems continuously test the motor insulation whenever the motor is offline and before every startup with a current limited direct current voltage. This allows the maintenance team to know ahead of time when a motor is unsafe to operate due to moisture or contaminant buildup. It would also give them time to take corrective action before the motor was needed.

Since most motor failures occur at startup, the I/R testing system helped eliminate electrical equipment failures and improved the plant’s reliability while increasing personnel safety with its automatic operation. The engineer began installing these systems on 10 of the critical 480 volt line motors and two large 300 horsepower compressor motors. The company has since seen a significant cost savings in labor hours, along with increased equipment operating life.

By using automatic insulation testing and monitoring technology, plants can improve safety and reliability while also saving time, money and labor.