MOTOR ARMATURE HAVING DISTRIBUTED WINDINGS FOR REDUCING ARCING

摘要

An armature for a brush commutated electric motor having a distributed coil winding arrangement for reducing brush arcing and electro-magnetic interference (EMI). The winding pattern involves winding a first coil Cl into a first pair of slots of the armature. A second coil having a first subcoil portion C2a is then wound into the same slots as the first coil, while a second subcoil portion C2b of the second coil is wound into a pair of slots that is offset by one slot position from the first pair of slots. The two subcoil portions have the same number of turns, and the total turns of the two subcoil portions equals the number of turns of the first coil. A third coil C3 is then wound in the same slots as the second subcoil portion of the second coil. The third coil C3 has the same number of turns as the fir coil Cl. This pattern is repeated around the armature. In a two coil per slot armature, this pattern enables the magnetic axis of each coil to be maintained at a constant angular position relative to the commutator bars to which it is coupled without the need for using uneve numbers of turns for the two subcoil portions of each segmented coil.