US758378A - Alternating-current motor. - Google Patents

Description

No. 758,378. PATBNTED APR. 26, 1904.

' R. MONEILL.

ALTERNATING CURRENT MOTOR.

APPLIOATION FILED DEG. 4, 1902.

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R. MoNEILL. ALTERNATING CURRENT MOTOR.

APPLICATION FILED DBO. 4, 1902.

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No. 758,378. PATENTED APR. 26, 1904. R. MONEILL.

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ALTE TING CURRENT MOTOR.

AP ATION mum one. 4, 1902 mhwawvewboz $513 fl GMT/14213 g Patented. Apri1'26, 1904.

UNITED STATES PATENT OFFICE.

RALPH MoNEILL, OF NEW YORK, N. Y., ASSIGNOR TO ARTHUR ,O. GRANGER, OF PHILADELPHIA, PENNSYLVANIA;

AL'TERNATlNG-GURRENT' MOTOR.

SPECIFICATION formingpart of Letters Patent No. 758,378, dated April 26, 1904.

Application filed December 4, 1902. Serial No. 133,825. (No model.)-

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Be it known that I, RALPH MONEILL, a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements inAlternating-Current Motors, whereby I am enabled to utilize alternating currents for motive power with a nearer approximation than has hitherto been reached to the efficiency at which direct currents may be used and that without the necessity of using'more conductors than those used in continuous-current or in single-phase alternating current systems, of which the following is a specification.

This invention relates to electric motors,and is especially applicable to alternating-current motors of the commutator type.

The principal object of the invention is to devise an alternating-current motor of the type employing commutators which shall not be subject to such sparking that has heretofore attended the operation of such motors and prevented their general use. under commercial conditions.

The invention also comprehends other features of advantage, which will be referred to more specifically hereinafter.

In the accompanying drawings I have diagrammatically illustrated several forms of motors embodying the invention.

Figure 1 illustrates the invention applied to a motor of the series type. Fig. 2 illustrates a type of motor in which the field-current is advanced in phase beyond that of the armature. Fig. 3 is a type in which part of the field-circuit is advanced in phase and part is in series with the armature. Fig. 4 is a type of transformer-motor. Figs. 5 and 6 illustrate types of armature-circuits, and Fig. 7 is a detail showing a modified arrangement of the primary windings of the transformers.

In Fig. 1, D represents a source of alternating current, located at any desired distance from the motor, supplying energy to the mains m m. C is a converter, the primary of which is connected with said mains. The secondary of the converter is shown as consisting of two coils s s, similarly wound. One of with the brushes of the other circuit.

these coils is connected through the field windingF to the brushes 6 Z) and the other through the field-winding F to the brushes 6 6', thus supplying currents to energizethe armaturecircuits hereinafter described. Two or more energizing-circuits may be employed, according to individual conditions, and the circuits maybe derived from any convenient'so'urces. When taken from the transformers, as shown, for example, they must be wound parallel to each other upon the same secondary or may be-otherwise suitably arranged or may be so wound as to be under the influence of independent magnetic circuits, if so desired. Preferably the windings are parallel to each other, and the currents in them are coincident in phase. The armature A is provided with a plurality of circuits. In Figs. 1 to l two circuits are shown, one indicated by full lines and the other by dotted lines. These circuits are in this instance displaced with respect to each other and so arranged with respect to the brushesthat each armature-circuit is always connected with one or the otherof the energizing-circuits before mentioned; In order to displace the circuits, it is not necessary to actually displace the coils. Instead the respective coils may be wound side by side and the commutator segments properly displaced.

In the drawings the armature-windings are connected to alternate barsof the commutator, as indicated by letters 0 c, and the brushes 6 b are so positioned that each set of commutatorbars is always under at least one set of brushes and so that as it passes from under the brushes of one circuit it makes contact In the operation of the motor, therefore, no part of the winding of either of the armature-circuits will be short-circuited upon itself at any time, andeach armature-circuit will at all times be in connection with one or more of the energizing-circuits. For example, before one of the segments 0 0 passes from under the brush 6 another segment 0 will come under the brush 6, and at no time will two or more segments connected to the same winding'come under the same brush, so that no winding of part of the winding will be short-circuited or cut out of the circuit, the two circuits being independent. Since the coils of a motor inclose nearly all of the magnetic flux that passes through the armature, the reversal of the magnetic field. has heretofore induced relatively strong currents in the short-circuited armature-coils, which currents caused sparking and other disturbances. In my motor this transformer action cannot take place, because of the absence of short circuits. Two non-inductive rheostats R and R, connected by the bar 2, may be located in the energizingcircuits for the purpose of controlling the initial rush of current when starting and may also be used to reduce the running speed of the motor. Choke-coils with adjustable windings may be substituted for the same purpose and used in the same manner.

In Fig. 2 the energizing-circuits are connected directly to the brushes, and the fields F and F are fed with a current of the same periodicity, but of difierent phase, being advanced beyond the phase supplied to the brushes 6 7/. The advanced phase may be obtained by means of any of the usual devices for that purpose. D conventions-11y indicates a generator adapted to give the desired advanced phase, conductors m m connecting generator D with IVith this construction the advanced field electromotive force compensates for the greater reactance of the field, which tends to retard the current-wave more than in the armature. Thus the magnetism of the field and the armature may be adjusted to have practically the same phase.

It is not essential in connection with any of the forms of my motor that the energizingcircuits be derived from secondary coils on the same transformer. There may be an independent transformer for each circuit or the independent circuits may be derived in any convenient manner. In Fig. 2 C may represent two independent magnetic circuits or one common magnetic circuit for the primaries 50 an d p and sand s, and the primaries, as shown, may be in series, as shown, or in parallel, as shown in Fig. 7.

In Fig. 3 the fields F F are fed with cur rent of advanced phase, as in the type illustrated in Fig. 2, and the energizing-circuits connected to brushes 7) b are in series with the field and armature,as illustrated in Fig. 1. By thus windingv both circuits on the field-magnet there is a tendency of the currents to correct in each other the lag of current behind its electromotive force, and it is possible to bring the magnetism of the field and armature more nearly into phase with each other. In this instance I have diagrammatically shown at I) a different type of phase-changing device to indicate that any suitable means for obtaining the advanced phase may be employed.

I have illustrated a doubleswitch L L, the blades of which are operated simultaneously by a connecting-bars, adapted to connect the energizing-circuits with the taps g 71v 2 r/ it '5 from the secondaries of the transformers, and thereby vary the voltage of the energizingcircuits.

In Fig. 4: the invention is applied to a transformer-motor. In this instance the transformer is omitted as a separate element. The primary coils p p on the field-magnets are connected to the mains m m. The secondary coils s and s, wound on the field-magnets, are connected to the brushes and supply the energizing-currents thereto. In this instance series connections of the respective coils are shown in the drawings; but the connections might be in multiple, if so desired.

In the type illustrated in 1 to 4 the armature is shown as having two circuits; but it is to be understood that any suitable number of circuits or types of windings may be employed. For example, in Fig. 5 the armature is provided with three circuits, each of which is connected with its respective set of commutator-bars c c, 0 c, c" c. The brushes are arranged, as before, to always connect with all the armature-windings and not leave any winding until that winding is under the next brush. More than two energizing -circuits may also be employed, if desired.

By independent circuits it is to be understood that I mean such independence as preserves the electrical independence of the circuits between brushes of the same polarity. Thus in Fig. 6 is illustrated a type of armature with three circuits connected to the bars a (Z c, which though interconnected are independent within the sense that I have used that term. In this instance between brushes the circuits are independent. In Figs. 1 to 5, however, it will be noted that the circuits are not in any way interconnected.

Although I have herein shown the armature as the rotative element of the machine, it will be understood that the parts may be reversed and either element made the movable element. It will also be noted that I have referred to the circuits which supply currents to the armature as energizing-circaits, it being intended to include thereby such circuits as supply currents to the armature circuits irrespective of the source of supply of such currents.

It will be understood that I have herein illustrated conventional type of apparatus in connection with the description of my inven tion and that any suitable type of machine or V accessories may be employed to suit individual conditions. I therefore desire it to be understood that I do not herein limit myself to the precise constructions and arrangement of parts herein shown.

Having thus described my invention, I declare that what I claim as new, and desire to secure by Letters Patent, is

1. The combination of a plurality of independent energizing-circuits, and a plurality of independent armature-circuits, the latter being each adapted to successively make contact with each of said energizing-circuits without being at any time short-circuited upon itself and to always be in contact with at least one of the energizing-circuits, substantially as described.

2. The combination of a plurality of independent energizing-circuits, and a plurality of independent armature-circuits, the latter being displaced geometrically with respect to each other to prevent the formation of short circuits, and each adapted to always be in contact with at least one of the energizing-circuits, substantially as described.

3. The combination of a plurality of independent energizing-circuits, a plurality of independent armature-circuits, and sets of contact-segments for said armature-circuits,- said segments being so arranged that each armature-circuit is at all times in contact with at least one energizing-circuit, said contact being through but one set of segments, substantially as described.

4. The combination of a plurality of independent energizing-circuits, a plurality of independent armature-circuits, the latter being displaced geometrically with respect to each other to prevent the formation of short circuits, and each adapted to always be in contact with at least one of the energizing-circuits, and supplymains from independent I transformer secondaries connected to said energizing-circuits, substantially as described. 5. In an alternating-current motor, the combination with the alternating-current field and energizing circuits, of a plurality of independent armature-circuits, the latter being displaced geometrically with respect to each other to prevent the formation of short circuits, and each adapted to always be in contact with at least one of the energizing-oil' cuits, and means for maintaining a coincidence in phase between the magnetism of the field and that of the armature, substantially as described.

6. In an alternating-current motor, the combination with the alternating-current field and energizing circuits, of a plurality of independent armature-circuits, the latter being displaced geometrically with respect to each other to prevent the formation of short circuits, and each adapted to always be in contact with at least one of the energizing-circuits, and means for advancing the phase of the field-circuit with respect to that of the armature-circuit, substantially as described.

7 In an alternating-current motor, the combination of a field-circuit, a plurality of independent energizing-circuits induced by said field-circuit, a plurality of independent armature-circuits, and means whereby each of said armature-circuits is always connected to one or more of the energizing-circuits, substantially as described.

8. In an alternating-current motor, the com bination of a field-circuit, a plurality of independent energizing-circuits induced by said field-circuit, a plurality of independent armature-circuits, and means whereby each of said armature-circuits is always connected to one or more of the energizing-circuits, without being short-circuited upon itself, substantially as described.

Signed at Nos. 9 to 15 Murray street, New York, N. Y., this 3d day of December, 1902.

. RALPH MCNEILL.

Witnesses:

FRED. J. DREW, JOHN O. SEIFERT.

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