However, you have to go beyond basic insulation resistance testing to catch high resistance connections.Ī good method of finding high resistance connections is to measure the phase-to-phase resistance between each of the three windings (in a three-phase motor). This test is often misapplied, as it is easily misunderstood what minimum insulation requirements should be and that these readings must be temperature compensated. Many maintenance teams will occasionally test motor resistance to ground with a megohmmeter. Per the previously mentioned article by IEEE, “it is important to monitor and correct high-R connections for a reliable, efficient, and safe operation of the industrial facility”. How can you detect a high resistance connection?
Many times a motor, although initially in perfect health, is installed into a faulty power circuit, with a high resistance connection for example.Noah went on to write in an article in Reliable Plant that: The focus of today’s topic is the motor lead connections, which, done improperly, often lead to failure.Īccording to Noah Bethel of PdMA, a project conducted in 1994 on industrial power distribution systems “found that connectors and conductors were the source of 46 percent of the faults reducing motor efficiency”. You can find them at circuit breakers, motor starter terminals, disconnects, or anywhere on the power circuit where a connection is made. They are often the root cause of motor failures.Īccording to IEEE, “a high-resistance (R) connection in an induction-motor electrical circuit results in localized overheating and supply-voltage unbalance, which leads to a decreased efficiency and reliability and an increased fire hazard in the electrical distribution system and motor”. Loose, poor, heat, imbalance, and failure are a few often associated with high resistance connection, and for good reason. EECO loves to supply your electrical equipment needsĪ lot of words come to mind when the term “high resistance connection” is used, though reliability is not one of them.Motor Repair Shops for Reliability Programs.Condition Based and Preventative Maintenance Services.Automation and Electrical Products for Industrial Applications.Carolina-Eaton Automation and Supporting Products.Getting Started with Smart Manufacturing.EtherNet/IP, Connectivity, and Smart Manufacturing Services.Modernization Services for Aging Automation Equipment.Smart Manufacturing is Changing Industrial Automation.