Abstract:
A stator winding for a motor comprising main, left and right poles wound by a main winding and auxiliary winding(s) which enable relatively continuous commutation angle adjustment by imparting different excitation currents upon the different windings. The auxiliary windings accommodate load variations in all types of motors. In addition, circuitry is disclosed for incorporating the auxiliary windings in a bi-directional motor for facilitating reversal of rotation.

Description:
This application is a continuation-in-part, division, of application Ser. No. 07/583,236, filed Sep. 14, 1990 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the invention 
     The present invention relates to electric machines, and more particularly, to a stator having a plurality of lap-wound windings for allowing adjustment of the commutating angle. 
     2. Description of the Background 
     Conventional AC/DC rectifying motors, whether shunt excitation, series excitation or compound-excitation, all include commutating magnetic poles or brushes having a magnetic polar axis. The maximum load of the motor is determined by the commutating angle. 
     It would be greatly advantageous to provide a means for adjusting the commutating angle during rotation of the rotor to accommodate load variations. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a rotor winding which allows for adjustment of the commutating angle during rotation of the rotor. 
     It is another object of the present invention to provide a rectifying motor having a lap-wound stator with adjustable commutating angle which provides relatively continuous polar axis adjustment in accordance with the direction of rotation. 
     In accordance with these and other objects, the present invention provides a composite lap-wound stator which enables relatively continuous angle movement adjustment by imparting different excitation currents upon different windings for the convenience of commutation. The invention accommodates load variations in all types of motors, and is especially useful in bi-directional motors for facilitating reversal of rotation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments and certain modifications thereof when taken together with the accompanying drawings, in which: 
     FIG. 1 shows the layout of the stator windings according to one embodiment of the present invention, including main field winding W0 in the middle position and right W2 and left W1 lap-wound windings. 
     FIG. 2 shows the layout of the windings according to a second embodiment of the present invention, including main field winding W0 in the middle position, supplemental winding W3 in the middle position, and right W2 and left W1 lap-wound windings. 
     FIG. 3 shows the layout of a composite winding according to a third embodiment of the present invention, the composite winding comprising right W2 and left W1 lap-wound commutating windings. 
     FIG. 4 is a circuit diagram showing the embodiment of FIG. 1 configured for use in a compound-excitation rotation-reversing driving motor. 
     FIG. 5 is a circuit diagram showing the embodiment of FIG. 3 configured for use in a rotation-reversing driving motor. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The examples and characteristics of operation according to the present invention are described as follows: 
     Referring to FIG. 1, the stator is provided with at least three projecting poles T 0 , T 1 , and T 2 . 
     Auxiliary poles T 1  and T 2  may be identical in size, or alternatively, may be of different sizes as necessary. Main pole T 0  in the middle position may also be greater, smaller or identical in size than/with the auxiliary poles at either side. 
     The poles are wound as follows: 
     Main winding W 0  is wound around the three projecting poles, auxiliary winding W 1  is wound around the main pole T 0  and pole T 1 , and auxiliary winding W 2  is wound around pole T0 and pole T2. The position of the pole center of the resulting composite magnetic field depends upon the selection of the winding(s), and on the proportional magnitudes of the excitation currents imparted to the selected windings of FIG. 1. 
     The embodiment of FIG. 2 incorporates the basic embodiment of FIG. 1 and, additionally, the following: 
     A fourth winding W3 wound around the intermediate pole. Winding W3 may be independently excited for correcting the magnetic field wave shape, or alternatively, may be wound in series with the main winding W 0  of FIG. 2. 
     In the embodiment of FIG. 3, a pair of windings are incorporated as follows: 
     auxiliary winding W 1  is wound around the 
     intermediate pole T 0  and left pole T1, and 
     auxiliary winding W 2  is wound around the 
     intermediate pole T 0  and right-handed pole T 2 , and the position of pole center of composite field will be moved depending on the selection of excitation intensity among each winding as shown in FIG. 3. 
     The above-described embodiments have many practical applications in the field of AC/DC type series, shunt or compound motors, but are especially useful when used in a rotation reversing model. A circuit diagram of a rotation reversing motor incorporating the three-winding stator of FIG. 1, and its associated circuitry, is shown in FIG. 4 wherein: 
     Control switch SW1 is a double-pole double-throw switch having poles P3 and P4 respectively connected via brushes to the windings of armature A0. Contact P1 is connected to contact P5 through auxiliary winding W1. Main winding W0 is connected in series between auxiliary windings W1 and W2. Contact P2 is connected to contact P6 through auxiliary winding W2. 
     Left auxiliary winding W 1 , main winding W 0  and right auxiliary winding W 2  have identical excitation polarities, and all three series-connected windings are connected in parallel to power input terminals A and B for connection to a power supply; the motor A0 may be placed in positive or reversed rotation by means of switch SW1. More specifically, when P 1  is connected to P 3 , and P 4  is connected P 5 , W 1  is in parallel with armature A0 and in series with windings W0 and W2 between power input terminals A and B. Main winding W 0  is in series with right auxiliary winding W 2 , and windings W0, W1 and W2 are parallel to power input terminals A and B. The above-described configuration results in a positive-rotation compound motor. However, upon switching of SW1, P 2  will be connected to P 3 , and P 4  will be connected to P6. In this state, armature A0 will rotate in the reverse direction of operation. 
     A further embodiment of the present invention incorporating the lap-wound bilateral winding of FIG. 3, is as shown in FIG. 5, wherein either one of lap-wound positive rotation field winding W1 and reversal rotation field winding W2 may be switched in series with armature A501. In this embodiment, windings W1 and W2 have opposite excitation polarities relative to each other. The other end of the two windings W1 and W2 are respectively connected to contact points PF and PR of control switch SWD. Control switch SWD is a single-pole single-throw switch having a common connection point COM, and power input terminal A is wired directly to the point COM. Power input terminal B is wired directly to one winding of armature A501. 
     In operation, when the point COM of control switch SWD and contact PF are connected, the polar axis of field winding W1 and armature A501 are aligned in a positive rotation commutating angle, and the motor will operate with a positive operation. 
     When point COM of control switch SWD and point PR are connected, the polar axis of field winding W2 and armature A501 are aligned in a reverse rotation commutating angle, and the motor will operate with a reversed rotation. 
     Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiment herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. 
     For example, all of the above embodiments can be applicable to power generators. 
     It is to be understood, therefore, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically set forth herein.