How is a short in the shunt field of a DC motor best located?

Correct Answer: Option A — applying AC voltage to the shunt field circuit and measuring the voltage drop across each field coil

Applying a low AC voltage to the shunt field and measuring the voltage drop across each individual coil allows for precise comparison. Coils with shorted turns will exhibit a significantly lower voltage drop than healthy coils, providing a reliable, non-destructive method to isolate the faulty field winding per standard electrical troubleshooting practices.