When performing predictive maintenance, it's important to use the right tool for the job.
Facilities are steadily crowding more equipment into less space while eliminating planned downtime for maintenance. As these companies try to maximize the revenue per square feet of their facilities, the pressure is on the electrical worker to keep production equipment running without interruption. Now new tools and maintenance strategies relieve you from some of this pressure. These tools help increase uptime and reliability at lower cost by allowing you to predict and prevent failure.
Electrical workers approach predictive maintenance (PdM) in several ways, and the selection of instruments and techniques available for PdM is vast. Although not everyone's tool box will look the same, certain items need to be on everyone's list.
Early power monitors were forensic tools — they told you what went wrong after the fact, but they didn't help you prevent the problem. A modern power monitor shows how your power looks at different points in your facility at different times. You can watch power events develop and take corrective action before failures occur. Power monitors are now loaded with alarm options, storage capabilities, and communications features, such as paging, e-mailing, and remote control.
A simple interface gives you advanced reporting with the information you need to keep the power on, or correct threats to power quality. For example, your power monitor can pinpoint the cause of a random voltage imbalance. Since a voltage imbalance of only 2% significantly decreases motor life, just one such pinpointing may pay for the power monitor.
Insulation resistance (IR) testers.
Periodic IR testing allows you to trend deterioration in cable insulation and replace cables before they fail. Data centers and other high-uptime facilities switch between redundant systems to allow for such testing without shutting down. If you plot a trend line against time, you can predict when certain cables will fail and schedule replacement well ahead of time — before a process interruption and before a fault.
IR testers also help determine the health of motors. The main limiting factor in the life of a motor is insulation life. Theoretically, you can predict motor failure if you plot insulation against time. In the real world, this holds true only when you conduct the tests frequently, because motors are subject to much higher abuse than cables. If you want high motor availability, consider automatic IR testing. Then you shouldn't have to guess when you should pull a motor for a rewind.
Infrared imaging equipment.
Infrared thermography gives you a picture of heat in your electrical system. Thermography can reveal several problems like bad connections, overcurrent, bad insulation, or poor ventilation — all of which will lead to failure. Now that infrared cameras are a fraction of the price they were a few years ago, it's much easier to own one. However, it may not be cost-effective to buy an infrared camera if it's going to be operated only once or twice a year by an untrained person; you can hire a skilled thermographer who has completed formal classes in thermography and routinely works with those skills in a variety of situations.
Using similar technology, infrared guns can find loose connections, identify open fuses, find overheated breakers, and troubleshoot HVAC systems. An infrared gun gives you a non-contact way to see if your connections are loose, because loose connections will be hot. Open fuses don't carry current, so they won't be warm.
A breaker can overheat for several reasons, and they all require attention. For example, it may have a corroded contact. Unless you can measure the heat, you aren't likely to know a problem exists until a failure occurs. With an infrared gun, you can quickly trace down frozen or overheated contacts. Without it, you'll have to use a more time-consuming methodology.
Digital multimeters (DMMs).
Today's DMMs have a wide range of capabilities. They also have enhanced safety features and communications and an arsenal of accessories. Not only can you use DMMs to test the traditional three (voltage, current, and resistance), you can also use them to measure capacitance, frequency, and temperature.
Go beyond the basics with fast sampling rates, selectable sampling rates, true rms, offset, crest capture, backlist display, autoranging, diode testing, and continuity testing as your needs dictate. Some meters also have low battery indicators and an analog bar graph in the LCD area. Meters that display the waveform while including DMM functions help troubleshoot power quality problems and motor drives, though more specialized meters are a better investment if you have to troubleshoot these kinds of problems on a regular basis. But remember, no single meter will meet all of your needs, so it's good to invest in more than one.
Hand and power tools.
Today's industrial-grade, battery-powered tools have ergonomic grips and long-lasting batteries that can help you to be more efficient on the jobsite. Such advanced tools reduce the need to string and protect miles of portable cords and plug-in stations. Portable cords are still important, though — for example, you might use one to power one of the new generations of portable benders or cable-pulling equipment. Today's models are light and flexible, even in cold weather.
If you're doing custom panel work in the field, the right tools will allow you to do the job with a factory look at a low cost. Punches now exist for all the standard shapes (including square) and sizes that panel devices require. You should also have a labeling device to make the wiring error-free and neat in appearance.
Computerized maintenance management systems (CMMSs).
Tools exist for administering maintenance, too. As CMMSs continue to evolve, they're being incorporated into the information systems architecture of entire companies. As such, the CMMS is now the standard for planning and tracking maintenance activities. With the rise in popularity of wireless connectivity tools, including cell phones and laptops, maintenance electricians can now receive work orders and record project data in the field via personal digital assistants.
Proper preventive maintenance starts with an examination of the way you maintain your facility and the selection of the tools that will help you do it faster, better, and safer. The proper tool for the job may be as simple as a wrench or as complex as a wireless Internet network, but it's up to you to determine what you need to keep your system up and running. Regardless of what your job calls for, advances in maintenance tools have created a wide variety of options to meet almost any need.
Sidebar: Don't Forget Training
Maintenance activities sometimes cause equipment damage and downtime simply because a maintenance worker doesn't have sufficient knowledge and experience for the task. When it comes to maintaining electrical systems, a mistake can be lethal for the maintenance person and catastrophic for the facility. At a minimum, maintenance workers should be familiar with the following:
Vendor manuals for the equipment under maintenance
NEC Chapters 1-5 and 9
NETA Maintenance Testing Specifications for Electrical Power Distribution Equipment and Systems
IEEE Green Book: Grounding and Bonding
IEEE Buff Book: Protection and Coordination
IEEE Yellow Book: Maintenance, Operation, and Safety
Training that covers basic test equipment and safety procedures will establish the foundation for a solid maintenance program.