What is the purpose of a growler test?

• A. To test the armature for opens and shorts
• B. To test bearings for wear
• C. To measure insulation resistance
• D. To test the field winding for leaks

Answer: (A)

A growler test is used to check the armature windings for faults such as opens and shorted turns. The test applies a magnetic field and looks for abnormal current paths in the winding. If a turn is shorted, a localized current path alters the magnetic field in a detectable way (often giving a noticeable indication on the tester or a slight drag), revealing a winding fault. If there’s an open in the circuit, there’s no current path and no indication of a fault. This test specifically targets the armature windings, not bearings, insulation resistance, or the field winding.