How hot is too hot? Motors and transformers have maximum operating conditions, but can I exceed those ratings on occasion and not damage the equipment?  In my years as an electrical insulation application consultant, the most common questions posed by end users regard insulation thermal classes and what effect they have on machinery reliability and life expectancy. Many articles have …

The stator core of a rotating machine is composed of multiple stacked layers to minimize eddy current losses. A short between two or more layers leads to higher local eddy currents. This in turn can lead to local hot spots, which in a worst-case scenario can cause a partial core melt and eventually damage the machine. A ring flux (or …

Measuring the winding resistance of generators and motors is one of the essential tests used in factory acceptance testing and during periodic routine testing procedures. This test can detect various problems in rotating machine windings, including a turn-to-turn short circuit in windings, which reduces a motor/generator’s ability to produce a balanced magnetic field, and a phase-to-phase short circuit, which in …