Incorrect brush pressure can result in accelerated brush wear on a DC generator. What statement concerning brush pressure is true?

Correct Answer: Option D — There is an optimal pressure range that results in minimal brush wear. Brush pressures above the optimal range cause excessive mechanical wear, and brush pressures below the optimal range cause excessive electrical wear.

Proper brush pressure is critical; excessive pressure accelerates mechanical wear through friction, while insufficient pressure causes micro-arcing and excessive electrical pitting. Maintaining the manufacturer's optimal range balances both mechanical longevity and electrical integrity.