Motors and drives, ubiquitous in industrial settings, can and do fail. To prolong motor life and save energy, five tests or inspections are frequently recommended: thermal, vibration, shaft alignment, insulation resistance and electrical measurements. All are fairly quick and easy to complete using handheld tools and the tests tell you a lot about system performance.
In addition, new wireless tools enable you to centrally capture, store and save data about the equipment in real-time or over time, including when the equipment is operational. With wireless meters, shut the system down, lock out, hook up a meter, close the panel door, re-engage, and start monitoring measurements.
Here is a brief rundown of five essential tests for motors and drives:
Thermal Inspections
Thermal inspection of the electrical and mechanical motor components with an infrared camera. High temperatures alone don't necessarily signal a problem, but a component with a higher temperature than similar components, or a rise in temperature, might mean something is amiss.
Insulation Resistance Testing
Insulation resistance testing can enable you to get a motor back into operation the easy way, by simply replacing a cable. An insulation multimeter like the Fluke 1587 FC Insulation Multimeter combines the function of insulation resistance testing with all of the most common digital multimeter functions. Measuring the insulation resistance of motor windings, you can detect deterioration caused by heat, age, corrosion, dirt, moisture, and excessive vibration before the motor fails.
Electrical Current Unbalance
Electrical current unbalance is a common root cause of motor overheating. Current unbalance can be caused by several different things, including power delivery problems, low voltage on one leg, or insulation resistance breakdown inside the motor windings. An instrument such as the Fluke 438-II Three-Phase Power Quality Analyzer can check all three legs of a three-phase system at the same time, and can detect transient voltage as well. An ac current clamp meter can also check the current draw on each of the three legs. With the Fluke ac3000FC and a Fluke Connect application readings can even be taken while the machine is in operation and the measurements can be easily saved and shared using a smart phone.