In a magnet stirring apparatus comprising a base which includes a plurality of magnet coils and onto which respective vessels can be placed, said vessels being made of a non-magnetic material and each containing a magnetic stirring bar as well as the liquid to be stirred, the stability of the stirring operation within a wide range of lengths of stirring bars and of adjusted rotational speeds is achieved by pole shoes which are long straggling in the radial direction toward one center.

Stator assembly for single phase induction motor

Magnet stirring apparatus

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.

Brush dc motors and ac commutator motor structures with concentrated windings

A novel stator assembly, D.C. electric motor, and method of controlling the speed of the motor is described. The stator assembly includes a pair of field poles, each having a field coil wound around a shank portion, and a plurality of separately excitable field control coils wound individually around the field pole legs defining a face portion of the field poles. The field poles also have a core portion which provides a magnetic path between the shank and face portion. This core portion permits the magnetic flux in the field poles to shift across the face portion when one or more of the field control coils are energized magnetically subtractive to the flux generated by the field coils. The speed of the motor may be controlled by energizing the field control coils and controlling their polarity with respect to the field coils. A motor controller for the motor according to the present invention is also described, and is particularly useful in an electric vehicle application.

Speed control of a D.C. electric motor

Stator assembly for a motor includes slotted magnetic core with main and auxiliary windings in core slots. Main winding comprises at least two sections each forming a main pole. Auxiliary winding in form of a starting winding also includes at least two sections forming poles angularly displaced from the main poles. Each starting winding is formed of a material that yields the same motor operating performance as a copper starting winding design with a backlash section and yet is provided with fewer, if any, backlash turns as compared to such copper winding arrangement. Preferred auxiliary winding materials have an electrical conductivity of about 29% IACS (International Annealed Copper Standard), a density of about 0.1 pound per cubic inch, and a specific heat at 25 DEG Centigrade of about 0.2 calories per gram per degree Centigrade. When alloy materials are used, the major alloying material or materials, in terms of percentage by weight of the alloy, comprise a sufficiently large percent of the alloy (by weight) that normal manufacturing and processing variations causing variations in the amount of such alloying material or materials still permit the economical manufacture of an alloy having a desired nominal resistivity.

Stator assembly for single phase induction motor employing aluminum alloy starting winding

A stator, for use in an alternating current motor, includes a core having a plurality of angularly spaced slots. A distributed main winding is concentrically arranged in a plurality of the slots, with these slots encompassing a first arcuate region of the core, less than its circumference. End turns for the main winding are positioned adjacent an end face of the first arcuate region of the core. This provides a second arcuate region of at least one end face of the core free of the main winding. In a first embodiment, an auxiliary winding, displaced in phase from the main winding, is received in a plurality of the slots, including at least some slots in the second arcuate region. In the first embodiment, end turns of the auxiliary winding in the second arcuate region are disposed inwardly of the radially outermost edges of the slots in the second arcuate region along at least one end face of the core. In a second embodiment, the second arcuate region of one end face of the core is free of both the auxiliary winding and the main winding. .Iadd.

Stator assembly for single phase induction motor

Citations

Magnet stirring apparatus

Brush dc motors and ac commutator motor structures with concentrated windings

Speed control of a D.C. electric motor

Stator assembly for single phase induction motor employing aluminum alloy starting winding

Stator slot and winding arrangements

References

Electric motor winding arrangement

Stator winding arrangement in a shingle phase induction type motor

Single phase induction motor

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