An electric motor 10 has a stator 14; a wound rotor 20, including a commutator 28; and brush gear for connecting the commutator to a source of electrical power. The brush gear has at least two cage brush assemblies 34. Each cage brush assembly 34 having a brush 40 for making sliding electrical contact with the commutator of the motor; a cage 50 for guiding the brush 40 along a path towards the commutator; and a spring 70 for resiliently urging the brush 40 along the path through the cage 50. The spring 70 is a constant force spring having two coiled end portions which engage the cage 50 at a commutator end portion. The cage 50 has two fingers about which the coiled end portions of the spring 70 locate.