What does a growler test primarily check for in electric motors?

A growler test is a diagnostic procedure used to check the electrical integrity of an electric motor, particularly focusing on the armature. When performing this test, an alternating magnetic field is induced in the armature windings, which can help identify short circuits between the winding turns or to the motor core.

When the armature is shorted, it generates an abnormal magnetic field pattern, which can be detected by the growler's pickup. The presence of shorts can lead to overheating and can significantly affect the motor’s performance, causing inefficiencies or failure. Identifying a shorted armature is crucial for maintaining motor health and preventing further damage.

In contrast, while out-of-round commutators, broken field leads, and faulty voltage regulators can also impact motor operation, they do not specifically relate to the primary function of the growler test, which is aimed explicitly at revealing issues within the armature itself.