Motor Management: Data Necessary to Evaluate Motor Operations

By James Piper, P.E.  
OTHER PARTS OF THIS ARTICLEPt. 1: Motor Management Can Reduce Repair Costs by 50 PercentPt. 2: This PagePt. 3: How to Make a Business Case for Motor-Management Programs

Perhaps the most important element driving the success of motor-management programs today is their ability to give managers data they need to evaluate motor operations without having to take the motor offline. The systems monitor and record data on the health of the motor through a network of sensors, including its rotor or armature, stator, field coils, bearings, power quality, voltage and current levels, and its connection to the load it is driving. Managers then can analyze this data in real time, diagnose problems, or monitor trends over time to identify developing problems.

Identifying motor problems either by individual readings or by readings over time allows managers to identify motors most likely to fail, reasons for the failure, and the likely timing of the failure. This information helps managers pick the time to repair or replace the motor, rather than reacting when it fails. The results include lower labor costs, lower motor-repair costs, and fewer disruptions of operations.

One factor making the programs successful is their ability to test certain characteristics of motor operation without having to take the motor offline. Transducers applied to the motor and its driven load enable technicians to measure vibrations and identify imbalances in the entire drive system, as well as the magnitude of those imbalances.

Having the ability to test motor-operating characteristics without having to remove the motor from service gives managers a wealth of information on the condition of the motor and its components. But additional testing technicians can perform with the motor offline provides equally important information. Offline tests typically can identify faults such as turn-to-turn shorts, open turns, open coils, air-gap defects, rotor defects, loose and broken connections, and insulation breakdowns.

No single test exists that tells technicians everything they need to know about a motor's condition. Different tests evaluate different components of the motor system. But for a motor-management system to be effective, it must examine as many aspects of the motor's operations as possible.

Taken together, the test results will help managers identify motors in good condition, those that need close monitoring, and those requiring replacement immediately or soon. By using the system to track data over time, managers will be able to detect trends in motor performance and better predict the best time to schedule maintenance or replacement.

Most programs include software that can record and track data gathered from the facility's motors. Some can record the data automatically from motor-mounted sensors, while staff will have to enter some test data manually into the system. Managers in commercial and institutional facilities who already have a building-automation system or a supervisory control and data acquisition (SCADA) system should be able to interface the motor-management system software with the existing system, eliminating the need for a redundant communications system while allowing data sharing.

Continue Reading: Motor Management: Powerful Benefits

Motor Management Can Reduce Repair Costs by 50 Percent

Motor Management: Data Necessary to Evaluate Motor Operations

How to Make a Business Case for Motor-Management Programs

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  posted on 2/2/2010   Article Use Policy

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