The slow but continuous rotation of the energy meter (Induction type) when only the pressure coil is excited and no current is flowing through the current coil is called creeping. This error may be due to excessive friction compensation, excessive voltage supply, stray magnetic field, etc.
In order to prevent creeping at no-load, two holes of the same radius are drilled in the disc on the opposite side of the spindle.
Lap Winding:-In a lap winding the number of parallel paths (a) is always equal to the number of poles (p) and also to the number of brushes. In the given question number of poles is 4 hence the number of brushes will be 4.
Wave Winding:- In wave windings, the number of parallel paths (a) is always two and there may be two or more brush positions.