Given the sometimes frenzied movement in the effort to go green, maintenance management may overlook the fact that maintaining reliability can pay dividends towards efficiency while improving the bottom line. Each of the six fault zones: Power Circuit, Power Quality, Insulation, Stator, Rotor, and Air Gap impact motor efficiency. This tip focuses on the Power Circuit.
The power circuit fault zone is defined as the system of conductors and connections running from the point of origin of testing to connections at the motor. Any non symmetric change in the resistive element of a three phase circuit will create an imbalance in voltage and current.
This imbalance results in inefficient circulating currents that produce elevated winding temperature without performing any real work. A study conducted in the mid-1990's determined that more than 46% of the faults found in industrial power distribution systems that reduced motor efficiency stemmed from problems within the power circuit.