Brush dc motors and ac commutator motor structures with concentrated windings

Abstract

Structures of direct current motors or ac commutator (Universal) motors which use a concentrated winding on the rotor with coils wound around the teeth. The number of commutator segments is higher than the number of rotor teeth. Several coils are wound around the same tooth. The terminals of the coils are connected to different segments of the commutator. The parallel paths of the armature winding are perfectly balanced. An equal current distribution through the parallel circuits of the armature is maintained and there is no circulation current between these parallel circuits. The problems related to commutation are reduced because the value of the coil inductances is low. The copper volume of the end-windings, the Joule losses and the axial length of the motor armature are lower than a lap or a wave winding with interlocked coils. Two kinds of structures with a concentrated winding are presented: some with rotor teeth with identical dimensions and some with rotor teeth with different dimensions.

1 - 28 . (canceled)  
   
   
       29 . A direct current (DC) motor comprising: 
 a stator, including a number of stator poles  2 P and a stator core;    a concentrated-winding rotor, including: 
 a rotor core made of ferromagnetic material and separated from the stator core by an airgap,  
 a number of rotor slots S, and  
 a number of rotor teeth S, wherein each of the rotor teeth has same geometrical dimensions, wherein a plurality of non-overlapping coils of insulated wire is wound around each of the rotor teeth, and wherein each coil of the plurality of non-overlapping coils has two ends and is wound around a single tooth;  
   a commutator with a number of commutator segments Z; and    a number of brushes  2 B, with B being equal to or less than P,    wherein, for each coil of the plurality of coils, the two ends are connected to different commutator segments,    wherein each brush of the number of brushes has a width such that the brush can simultaneously touch only two commutator segments that are respectively connected to the two ends of a same coil, and    wherein at least two brushes of the number of brushes are arranged to respectively touch commutator segments connected to coils wound around a same tooth.    
   
   
       30 . The direct current (DC) motor of  claim 29 , wherein each stator pole comprises a permanent magnet mounted on a surface of a core made of a ferromagnetic material.  
   
   
       31 . The direct current motor of  claim 29 , wherein each stator pole comprises a coil wound around a tooth made of a ferromagnetic material.  
   
   
       32 . An AC commutator (Universal) motor comprising: 
 a stator, including a number of stator poles  2 P, each pole comprising a coil wound around a tooth of a stator core made of a ferromagnetic material;    a concentrated-winding rotor, including: 
 a rotor core made of a ferromagnetic material and separated from the stator core by an airgap,  
 a number of rotor slots S, and  
 a number of rotor teeth S, wherein each of the rotor teeth has same geometrical dimensions, wherein a plurality of non-overlapping insulated wire coils is wound around each of the rotor teeth, and wherein each coil of the plurality of non-overlapping coils has two ends and is wound around a single tooth;  
   a commutator with a number of commutator segments Z; and    a number of brushes  2 B, with B being equal to or less than P,    wherein, for each coil of the plurality of coils, the two ends are connected to different commutator segments,    wherein each brush of the number of brushes has a width such that the brush can simultaneously touch only two commutator segments that are respectively connected to the two ends of a same coil, and    wherein at least two brushes of the number of brushes are arranged to respectively touch commutator segments connected to coils wound around a same tooth.