Industrial Motor Health Tips and IIoT SolutionsOctober 11, 2020 by Jeff Kerns
Learn about tips and solutions to promote long-lasting electric motor health.
Industrial motors are quite literally driving manufacturing. Keeping electric motors healthy and operating properly can greatly affect production.
According to a report from the Department of Energy, an average motor’s life cycle might be from 30,000 to 40,000 hours. When it comes to motor health, regular monitoring and maintenance will increase its life cycle.
Parts and Problems
Industrial electric motors may not have many parts, which makes each piece important. Generally, there are windings, stator, rotor, bearings, and a shaft. Keeping motors clean and debris free will increase its life cycle.
One way motors stay clean from outside sources such as dust and water is by selecting a motor housing with an internal protection (IP) rating. An IP rating has two numbers. The first number indicates what protection the housing provides against solids while the second number is for water.
If motors are in a dusty or wash-down application knowing the motor's IP rating will be important. However, with or without an IP rating humidity, corrosion, and contamination can still occur. Often monitoring the temperature, and humidity of a motor's lubrication can indicate when a motor might require maintenance.
Maintenance and Wear
Some technicians might be able to use a pneumatic tool to blast a motor with air if there is any suspected contaminates or humidity built up within the housing of a motor.
Electric AC motor.
While this might help, it is important to understand how humidity and temperature can affect lubrication. Some motors and bearing are considered lubricated for life and should be left alone. In fact, this can lead to increased wear and tear by damaging seals and over lubricating.
Tip: Know your lubrication maintenance plan and use proper documentation.
Motors and bearings that require lubrication will not only need a maintenance plan but should have proper documentation. Technicians, managers, etc. should have access to maintenance information. This should include any manual or data from the OEM on operation specification and maintenance.
When it comes to documentation, the more information the better. For example, include the date and hours of operation. If an OEM indicates a motor to be re-lubricated every year based on a single shift of operation, but you use the motor for fluctuations in production, having the manufacturer's information, data, and operational hours of the motor will help ensure maintenance is done on time.
There are multiple ways to monitor lubrication. You can check filters for contamination before startup, or pressure, temperature, and flow sensors could provide information during operation. Many monitoring products offer a wide range of operations and applications so some sensors used on pumps or hydraulic applications may also work to monitor electric motors.
Tip: Documenting common events or normal operation data is also important. Common data can establish a baseline and how factors change over time. This data can help pinpoint if something is a common or special occurrence.
Monitoring lubrication isn’t the only variable to ensure a healthy motor. Data such as vibration and non-lubricant temperatures can help monitor motor health. Also, having more data can provide accurate information for predicting maintenance, preventing failures, or troubleshooting motor problems. One way workers are able to monitor or troubleshoot motors or bearings is based on how they sound.
A screech or squeal might indicate a lubrication problem. A clang or clatter might indicate that the bearing ring has deformed and needs to be replaced. Scoring on the ball or race in the bearings could produce a hissing sound. It may require years of exposure and experience to be able to pick up on these sounds.
Working environments might have ambient noise making sounds hard to detect. Also, human ears may not be able to detect a sound until it is too late and a motor must be shut down for maintenance.
Operating and Starting
While attentive workers are important, temperature and vibration sensors will provide higher fidelity and quality detection of motor performance. For example, variable frequency drive (VFD) motors are becoming popular in some applications. Operating at different speeds can cause vibrations to fall within the natural frequency of a system.
Workers might not be around, notice, or know why vibrations increase seemingly at random. However, sensor packages able to log data throughout operation might show an increase in vibration is only happening at a specific speed. Having this information can reduce or eliminate the time spent operating at speeds that cause excessive vibration.
Tip: If an application runs at a constant speed a VFD isn’t necessary and would incur a higher cost compared to a soft start solution.
Problems around VFD might be new for some, but most know that wear and damage on motors, bearings, and gearboxes can increase when a motor is started. While there isn’t much maintenance or monitoring can do to reduce this, devices can be added to provide a softer or more gradual start. Devices known as soft starters and VFDs can ramp up speeds to reduce wear and damage associated with starting a motor.
Healthy Motor IIoT Solutions
Tip: Most monitoring solutions center around, but are not limited to, a few factors: Temperature, vibration, and humidity.
There are many monitoring devices available. Fluke offers a thermal imaging camera that can show the temperature of a motor. It can’t look inside, but most industrial motors will have a tag indicating a normal operating temperature that the camera is able to verify at a glance. Additionally, thermal cameras are able to detect temperatures over the entire motor or an area that can help when troubleshooting temperature concerns.
A thermal imagine camera. Image courtesy of Fluke.
There are many types of vibration sensors. Some solutions are easier to retrofit depending on your equipment. For low-voltage motors, ABB offers a sensor package that is easy to integrate, wireless and claims a five-year battery life. The package is installed on the outside on the motor and is able to collect data for a month. Data is able to download to mobile devices that have ABB’s app. As long as a mobile device comes within a couple of meters of the sensor package at least once a month there shouldn’t be any gap in data.
Wireless sensors reduce the needed infrastructure and wires to integrate monitoring devices quickly for manufacturing and motor applications. Parker Hannifin offers battery-powered SensoNode wireless products that are able to monitor pressure, temperature, and humidity in many applications.
This line of products is Bluetooth enabled, but other companies offer Wi-Fi, Sigfox, LoRA, cellular, and RF communication.
Understanding the bandwidth, power, and distance these technologies provide is important to know when applying them to your application. Some wireless technology might have limits on how many products can communicate reliably.
Some companies have come out with developer kits. Simply offering a sensor packet, downloadable software, and developer tools so companies can create their own solutions. For example, Bosch Rexroth’s XDK can be strapped to a motor and start collecting data. These products are more for experimentation and exploration than a permanent solution, but provide a lot of value.
Whatever you use, paper and pencil, connected sensors, etc. monitoring and documenting motor information will give you the data needed to keep motors healthy and improve life cycles. Many companies are adopting more advanced solutions as companies such as ABB report that monitoring with smart sensors can improve energy efficiency by 10%, extend a motor’s lifetime by 30%, and decrease unplanned downtime by 70%.