What Other Predictive Maintenance Strategies Can and Cannot Do

There are several solutions for predictive maintenance employed in the industry today. Some of the leading industry solutions are discussed here. These solutions lack their ability to provide continuous monitoring of crucial metrics to predict the health of the equipment in real-time.

Handheld infrared imaging device to detect motor hot-spots*

Infrared devices

Infrared devices come in two common types used to detect hot-spots in plant equipment: the laser-pointer type and the imaging type. The laser pointer measures average heat energy over an area, but does not give precise measurements of spot temperatures. Their accuracy is sensitive to read distance and angles. With the laser pointer it is difficult to determine if a stopped motor’s core is cool enough to tolerate the heat spike from a restart. Imaging infrared devices are superior at detecting spot heat sources, but they often give false readings. If the object being monitored has a reflective surface, or easily reflects heat, this can badly confuse the reading. Although infrared devices may seem simple to use, they must be used by well-trained workers.

Vibration analysis

Vibration analysis can be used to recognize misalignment, defective bearings, or loose parts in electric motors. Proximity sensors, velocity sensors, and accelerometers are examples of vibration analyzers. These sensors can be costly on a per-node basis. Although they are small, some sensors require external power and a complicated installation. This incurs costs both to install and maintain the sensors. They need a fine-tuned calibration and are often susceptible to outside noise, which confuses the readings.

Manual testing of industrial motor**

Performance testing

Performance testing is a commonly done on motors and other industrial equipment. These tests are used to measure motor efficiency or evaluate performance under varying load conditions. Such methods can incur large cost in terms of equipment downtime and the tools requires to execute these tests. Performance checks cannot accurately reproduce all real-world conditions, like length of continuous use, occasional power surges, or load conditions, thus limiting their efficacy.

Hand testing

Hand testing was the traditional means of gauging temperature of running motors. Motors were once over-specified for their loads, making them more robust at the cost of inefficient energy usage. Historically, an operator had little risk that a motor would overheat, and could even put their hand directly on the motor casing to check for anomalous heat conditions. Today, motors are specified very near their thermal limits and can now operate well over 100°C. Touching a motor is no longer a safe or viable option.

Continuous temperature monitoring is preferable over intermittent monitoring for predictive maintenance solutions. RFMicron’s sensors add further value by being passive and thus requiring little to no maintenance overhead after installation. A complete solution from RFMicron is a major savings in installation and maintenance costs compared to either an IoT system or a vibration sensor that requires wires and batteries. More efficient than performance testing or scanning motors with an infrared device, RFMicron can also provide savings in time and an easy-to-use system.

To learn more about our solution and its deployment, read more in the next blog post.

*Image sourced from: http://www.ipesearch.co.uk/page_734155.asp on Nov 10, 2017.

**Image sourced from: http://www.studyelectrical.com/2014/03/testing-of-dc-machines-dc-motor-and-dc.html on Nov 10, 2017.


In case you missed the previous posts in this Series, here they are:

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