2007 Best Practices Awards in Predictive

Read about the winner (and runners up) of the 2007 Best Practices Awards predictive category.

By Paul Studebaker, CMRP, Editor in Chief

Winner: Detect thermal problems with online non-contact IR thermometry

Thermal monitoring systems employing noncontact infrared (IR) sensors can measure temperature just about anywhere on the factory floor. These versatile devices measure and accumulate real-time data, and are well suited for environments with moving targets, inaccessible objects and high temperatures. An IR thermometer has no energy interference (thus, no energy is lost from the target), and no risk of contamination or mechanical effect.

IR sensors incorporating a miniature sensing head and separate electronics can be located in confined spaces close to hazardous process areas. They are able to withstand ambient temperatures as high as 180° C without any cooling, and cover measurement ranges from approximately -40°C to 600°C.

Unlike standard thermocouples, IR sensors don’t require any type of electrical isolation. The sensors can provide 20:1 optical resolution (a 1 in. diameter target can be measured from a 20 in. distance), avoiding the danger of accidental contact with high-voltage equipment.

For example, IR sensors allow maintenance staff to check for heat produced by loose electrical connectors or corrosion buildup; locate problems in battery banks and power panel terminations, ballasts, switch gear and fuse connections; and identify hot spots.

In a typical plant application, maintenance workers might use an IR-based thermometer to monitor the performance of a motor driving an air conditioning unit. Installing a permanent sensor makes it easier to detect overheated bearings or other hot spots and implement true predictive maintenance procedures.

IR sensors also can be used to keep track of electrical phase temperatures affecting motors, pumps, belt drives and other machinery. By continually monitoring phase temperatures, technicians can detect overload conditions on one or more phases, as well as identify phase distortion or imbalance.

As power demand rises in data centers and manufacturing plants, their electrical switchgear and distribution components need to handle the increased load. Currently, many companies perform annual thermography scans for predictive maintenance. But at some point between normal maintenance intervals, system components may reach a premature limit. Continuous thermal monitoring solutions with trending and graphing capabilities enable technicians to review temperature data, decide how well equipment is performing and look for problems occurring under specific operating conditions or during certain production periods.

Continuous thermal monitoring provides a safer, non-intrusive alternative for equipment inspection. With traditional physical maintenance, there always is a chance of an accident causing failure of the equipment or putting personnel in harm’s way. In the worst-case scenario, a technician can be killed from an accident or arc flash. Noncontact thermal monitoring eliminates concerns about electrical isolation, insulation and EMI flashover associated with contact probes. IR sensors can accurately measure temperature without contacting the surface of the target.

In the case of electrical switchgear, thermal measurements are sometimes limited to snapshot scans through a glass observation window ­ a safety interlock will disable the unit if its enclosure door is opened. IR sensors allow precise temperature readings to be taken without accessing the equipment and under full load conditions.

Thermal monitoring systems can provide alarms alerting operators when maximum temperature levels have been reached. Reviewing alarms and/or trend data can highlight a problem before it grows into an expensive failure or catastrophic event.
Raytek, www.raytek.com.


Alarm and event archiving speeds recovery from unplanned shutdowns

A North American energy producer’s SCADA system couldn’t provide accurate event time stamp of the alarms or store the alarms for later use, noticeably increasing recovery time from an unplanned shutdown. The company implemented a system to store and view alarm and event data from the sequence-of-events recorder in its PLC controls system. The ability to store and view events lets maintenance personnel accurately and expediently troubleshoot the system. Easy access to data lets engineers provide confident support, reducing maintenance, downtime and lost revenue.
Matrikon, www.matrikon.com.

Monitor machine tool spindles to prevent out-of-spec products

Recognizing that out-of-tolerance production is worse than an unplanned outage, an engine component plant is piloting vibration-based condition-monitoring systems on machine tool spindles. The pilot is intended to determine how far in advance bearing damage can be detected, reduce stoppages caused by bearing or other machine-induced failure (i.e. unbalance, misalignment, resonance), compare predictive to time-based and run-to-failure strategies, and increase knowledge about design and implementation of spindle-monitoring systems.
SKF, www.skf.com.

Monitor machine tool cells with a centralized PC-based SCADA system

An engine plant installed PC-based cell controllers to monitor CNC machine tool operations and alarms, and bring information into production monitoring, control and annunciation systems. Alarms are processed and sent to display boards for immediate attention by service personnel, and equipment functions are monitored plant-wide for analysis and process improvements.
Siemens, www.siemens.com.

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