One method of testing for a reversed shunt field coil in a DC motor is by connecting the coil to a low voltage source, and testing for polarity. How is this done?

Correct Answer: Option A — placing a magnetic compass near each field

Passing low voltage through a field coil creates a distinct magnetic field. Moving a magnetic compass across each adjacent pole piece verifies alternating north and south polarities. Per IEEE 45, a reversed coil fails to deflect the compass needle correctly, indicating a polarity error.