Starter generator with slots in the commutator head assembly

A starter generator having one or more brushes wherein the brushes comprise the following percentages by weight:

• Boron <0.002
• Iron <0.015
• Copper <0.002
• Molybdenum <0.002
• Magnesium <0.02
• Silicon <0.015
• Silver <0.60
• Aluminum <0.002
• Calcium <0.15
• Phosphorous <0.02
• Sulfur <0.02
• Potassium <0.02
• Nickel <0.002
• Cobalt <0.002
• Manganese <0.002
• Titanium <0.002
• Vanadium <0.002
• Zinc <0.02
• Lead <0.02
• Lithium <2.0
• Lithium carbonate <5.0
• and wherein the remainder is carbon.

A starter generator for a helicopter comprising

• a body with an end bell,
• a commutator head assembly having a sidewall with an upper portion and a bottom portion, said sidewall having one or more air outlets in the upper portion of the sidewall in said commutator head assembly and
• a fan cover assembly, and
• wherein the commutator head assembly comprises a frame with a top end and a base end, the top end being adapted to fit within the fan cover assembly and be retained therein by a suitable means, the commutator head assembly having a plurality of slots in the bottom portion of said sidewall of said commutator head assembly that are designed to exhaust air flow passing over one or more brushes in the starter generator.