Pumps & Systems, November 2012
Maintenance and energy efficiency are key concerns for plant managers and process engineers. Controlling these costs contributes to organizations’ overall bottom line. Continuously monitoring key failure indicators with remote monitoring solutions helps facilities respond to equipment problems sooner.
Because many processes run continuously, preventing downtime and scheduling maintenance are crucial. At the same time, electric motor-driven systems used in industrial processes consume an estimated 23 percent of all U.S. electricity sold. As energy costs continue to increase, understanding the methods of motor and pump control and protection is increasingly important for industrial users.
Nearly every motor and pump in an industrial facility uses some form of motor protection. Different levels are available, and understanding the options is important, because spending too much can offset predictive maintenance benefits.
Condition Monitoring Systems
Condition monitoring makes use of sophisticated technologies and tools to assess equipment condition and predict potential equipment failure. Condition monitoring can be critical to predictive maintenance. The information helps schedule maintenance, avoid equipment failure and prevent downtime.
Condition monitoring systems typically incorporate vibration sensors, pressure transducers, resistance temperature detectors (RTDs) and other means of measuring temperature—such as infrared scopes and other sensors. Condition monitoring systems require extra assets and personnel to collect the data.
|Figure 1. Spectrum of ways that condition monitoring adds value
A small percentage of critical motors and motor loads in the U.S. are equipped with condition monitoring systems. This is because of costs, time and the complexity of many systems. Condition monitoring is usually used for the most critical and expensive equipment. In a high percentage of low-horsepower, critical loads, condition monitoring is not used. Therefore, low-horsepower systems are more likely to experience unscheduled downtime or inefficient equipment operation.
Although only the most critical and expensive equipment is typically monitored by condition monitoring systems, most motors in a pumping system use motor protection—the overload relay. Advanced overload relays provide a host of advantages:
• No large investment need
• Achieve 100 percent motor coverage
• Continuous data
• Non-invasive and no firewall issues
• Data for action locally or at the system level
• Optimize labor practices—targeted inspections