Electric motor commutator brushes arrangement - has blocks which hold outer brushes in reserve until inner brushes are worn down when outer brushes are then brought into contact with commutator.

摘要

A commutator brush arrangement for electromotors has two pairs of spring-loaded brushes (10,11). The outer brushes (11) are held in a reserve position at a distance from the commutator (4) by displaceable blocks (14). These are held under the effect of springs (13) on the cladding of the inner brushes (10). The inner brushes (10) have grooves at their ends perpendicular to the elongate direction. The blocks (14) can engage in these grooves (12) when the brushes (10) are worn down. In this position, the blocks (14) allow the outer brushes (11) to contact the commutator (4). ADVANTAGE - Prolongs the life of the electromotor without increasing the space requirement.