The tongue-in-cheek saying “If it’s in black and white, it must be right” is a helpful reminder that not everything we read (or hear) is accurate or complete. It’s always best to check sources and verify facts before accepting consequential statements as true. This article provides a selection of common misconceptions about three-phase squirrel-cage motors and the facts that deny them.

Here is a random collection of some relatively common misconceptions about three-phase squirrel cage motor performance characteristics.

Aquí tenemos una colección de algunos de los conceptos errados más comunes acerca de las características de desempeño de los motores eléctricos tipo jaula.

This paper, presented at the 2013 EASA Convention, will examine Power Factor Tip-up and Partial discharge testing to assess stator winding conditions for motors rated 2300 V and above. Both tests will be evaluated for: effectiveness; which windings/types of machines the test is effective; set-up; interpretation and limitations.

In large office buildings or industrial settings, the power factor should be maintained close to unity. The benefits in doing so are as follows: The losses in the cables and other equipment can be reduced because the current flow through them is reduced. This, in turn, reduces heating, and hence aging. In addition, the requirements for circuit interrupting devices are less onerous. So smaller or less expensive ones can be used. Finally, energy costs can be reduced by eliminating or reducing utility surcharges. Note that not all utilities penalize the user for low power factor.

In electric motors, power factor varies with load (although not directly). A motor running without a load will have a very low power factor, whereas at full load, the power factor may be relatively high. A facility that has a very low power factor in the total system may be charged a penalty by the power company for "borrowing" the power without fully using it. This is because more current is being transmitted than is actually doing any useful work.