Brush holder assembly for dynamoelectric machines

A brush holder assembly that, by design, cannot be assembly incorrectly is disclosed. The brush holder assembly includes a brush inserted into a brush holder, a block attached to the top of the brush, a spring engaging the block so as to apply radial pressure to the block and brush, and a hook pin engaging the spring and the block so as to hold the spring onto the block. The block includes a semicircular indentation that cradles a coiled portion of the spring. The block also includes a slotted hole for receiving a portion of the hook pin as the block is glued to the top of the brush. The hook pin is preferably a loop terminating at a first end that is a substantially straight pin and terminating at a second end that is a hook-shaped loop in which the straight pin end is inserted. The hook pin is formed from a spring biased metal to facilitate insertion of the straight pin end and into the hook-shaped loop end. Alternatively, a spool assembly can be used to engage the coiled portion of the spring so as to lock it in the indentation in the block. The spool assembly is U-shaped with a first upright end that supports a first spool holder and a second upright end that supports a second spool holder, the first spool holder and second spool holder each engaging and supporting an end of the coiled portion.