Method of producing an electrical component

A method for producing a brush for a dynamo electric machine comprising the steps of:

• providing a powder mixture consisting essentially of copper, lead, carbon and a hard phase, compacting said powder mixture under an applied load of between substantially 10 tons per square inch and substantially 35 tons per square inch to form a powder compact defining a brush body having a thickness of between substantially 0.30 inches and substantially 0.32 inches and having a mounting surface and an opposite commutator engaging surface, providing a conductive support member, positioning said conductive support member in electrical contact with said mounting surface, urging a pair of electrodes against said support member and said powder compact at an applied load of substantially on the order of 20 lbs. force, and simultaneously with said urging, passing an electrical current of between substantially 1500 amperes and substantially 1800 amperes through said conductive support member and said powder compact for between substantially 1.5 seconds and substantially 2 seconds to precondition said powder compact and thereafter passing an electrical current, while maintaining said urging, of between substantially 2200 amperes and substantially 2400 amperes for between substantially 5 seconds and substantially 6 seconds for sintering said powder compact and electrically connecting said conductive member to said powder compact.

A method of producing a brush for a dynamo electric machine comprising the steps of:

• providing a powder mixture consisting essentially of copper, tin, lead, carbon and a hard phase;
• compacting said powder mixture to form a powder compact;
• providing a conductive member;
• positioning said conductive member in electrical contact with said powder compact;
• said conductive member being of larger area than the contacting area of the powder compact in contact therewith;
• and thereafter, passing an electrical current of predetermined magnitude through said conductive member and said compact to heat said compact and said member for sintering said compact and electrically connecting said conductive member to said compact;
• the step of passing an electrical current of predetermined magnitude through said conductive member and said compact comprising the steps of first passing an electrical current of a first predetermined magnitude through said member and said compact for preconditioning said powder compact and thereafter passing an electrical current of a second predetermined magnitude through said member and said compact for sintering said compact and connecting said conductive member to said compact, and wherein said first predetermined magnitude is less than said second predetermined magnitude.