Untitled record

Application filed January 28, 1884. Serial No. 118,996. (No model.)

To all whom it may concern:

Beit known that we, Elihu Thomson and E. Wilbur Rice, citizens ofthe United States, and residents of Lynn, in the county of Essex 5 and State of Massachusetts, have invented certain new and useful Improvements in Regulators for Dynamo-Electric Machines, of which the following is a specification.

Our invention relates to current-regulators io for dynamo-electric machines, and its object is to provide a more efficient adjustment or regulation than is attained by the regulators or governors at present in use, and also to improve the class of governors in which the cur15 rent strength is controlled by varying the strength of the magnetic field in which the armature of the machine revolves.

Our invention consists, broadly, in the combination of means for varying the strength of 20 the magnetic field in which the armature revolves and means operating simultaneously to adjust the commutator.

In carrying out our invention any devices or means for varying the strength of the mag25 netic field may be employed, and the adjustment of the commutator may be either an adjustment of the commutator-cylinder or of the commutator-brushes. The adjustment may be of such nature as to cause the commutator30 brushes to follow or be maintained iu practical coincidence with the neutral point as the strength of the field is varied, or the simultaneous adjustment imparted to the commutator may be such that the variation of effect due 35 to adjustment of commutator toward or away from the neutral point shall be superadded to the effect due to variation of magnetic field. Thus, for instance, if the commutator-brushes be set forward at the same time that the field 40 is diminished, the adjustment forward may be such as to exceed the shifting of the neutral point caused by change in the magnetic field, so that the current will be diminished both by diminution in the strength of the magnetic 45 field and also by reason of adjustment of commutator forward or beyond the new neutral point existing with the weakened field. . If the commutator be adjusted so as to maintain the same relation to the neutral point that ex50 isted before the change in the strength of the field, the diminution of current will then be primarily due to change of field; but the disturbing effect due to changed relation of commutator to the neutral point that would ensue if the commutator remained unadjusted will 55 be avoided.

An important feature of our invention is to make the commutator, when adjusted, follow the shifting neutral point due to variation of the strength of field, and to thus avoid the 60 element of imperfection due in regulators working by change in the strength of the magnetic field to the fact that with a weak field the neutral point or point of change in the polarity of current on the armature is farther 65 removed from the geometrical neutral point in the direction of rotation than is the case with a stronger field.

In regulators working by variations of the magnetic field a decrease in the strength of 70 field carries the neutral point forward in the direction of rotation, leaving the commutator 'adjusted for the neutral point as it stood before the change. By providing a simultaneous automatic adjustment of the commutator 75 to correspond with the change in position of the neutral point we avoid any difficulties or disadvantages arising from this cause.

In the accompanying drawings we have shown a commutator adjustment effected by 80 moving the brushes forward or back ou the commutator-cylinder, because that is the simplest adjustment, mechanically considered. We, however, contemplate employing any kind of commutator adjustment whereby a change 85 in the current taken from the armature would be effected, or whereby the delivery-point of the current from the coils maybe adjusted with relation to the actual neutral point or point at which the polarity of the current is 90 set up as the armature changes.

Some of the various ways in which our invention may be carried out are illustrated diagrammatically in the accompanying drawings, in which— gFigure 1 shows the invention carried out in connection with a machine the strength of whose field is varied by variably shunting current from the field-magnet coils. Fig. 2 shows a modified detail of the magnetic ap- 100

339,079 paratus, whereby the desired adjustments are automatically effected. Fig. 3 illustrates another manner of varying the strength of the field - magnet. Fig. 4 illustrates another 5 method of carrying out our invention. Figs.

5, 6, 7, 8, and 9 illustrate other modifications that will be described in detail further on.

Referring to Fig. 1, F F indicate the fieldmagnet coils for a dynamo-electric machine of io any desired construction, and A the armature thereof,revolving in the magnetic field formed by the poles ofthe field-magnet. B indicates the commutator-cylinder, and C an adjustable yoke or other support of any ordinary or suit15 able description, carrying the commutator ' brushes aud adapted to be turned about the commutator axis so as to shift the brushes forward or backward on the cylinder. D D indicate the working-circuit, containing elec20 tric-arc lights or other working resistances,L. The field-coils F and the armature are in this instance in circuit with one another and with the working resistances, as usual in the art, and as shown. In said circuit, or connected 25 therewith, is a governing or regulating magnet, R, whose movable core is connected to a lever, d, that carries at one end a contact spring, g, adapted to move over a series of contactplates, P, each connected to a loop from a 30 series of resistance-coils, r, all arranged in a manner well understood so that the amount of resistance in the circuit 7 6, connected to g and to one terminal of resistances r, and forming a branch around the field-coils, will 35 be varied by the movement of lever d under the influence of magnet R. As the strength of R increases the lever d is moved so as to decrease the. resistance in the branch 7, thus shunting more current from the field-coils and 40 cutting down the strength of the field, while a contrary movement and an increase in the strength of the field results from a decrease in the strength of magnet R. Lever d is provided with a suitable retractor, 8, acting in 45 opposition to the magnet R, and with a dashpot, D², to prevent sudden and over movements of the parts.

The devices so far as described act to regulate the current upon the circuit containing 50 the working resistances by varying or governing the strength ofthe magnetic field in which the armature moves. In addition, there is a simultaneous adjustment of the commutator, brushes, either to follow or to exceed the shift55 ing neutral point produced by changes in the strength of the field, such adjustment being made in the present case to take place correspondently with the variation of the resistance in the shunt 7, by the simple expedient 60 of connecting the yoke 0 with the lever d by a link, d², so that as the strength of the field decreases by the adjustment of the resistance, and the neutral point consequently shifts forward in the direction of revolution, the com65 mutator - brushes will be. made to follow or move in the same direction, and to either re· tain the same adjustment with relation to the neutral point, or, if it be desired, to move beyond the point necessary to maintain the same adjustment. Such excess of commutator ad- 70 justment may be effected by any desired mechanical arrangement or relation of the parts. The magnet R is preferably of such construction as to have a uniform pull upon its armature or core in all positions of the latter with 75 the same strength of current. This may be effected by giving to the coil a larger number of turns near its bottom, or in any other desired way.

The magnet R may, if desired, be governed 80 by a second magnet, C, as indicated in Fig. 2, which magnet may be in a derived circuit, or in the main circuit, as indicated, and may govern contacts Q, that complete a shunt around magnet R when the power of coil C to hold up 85 its core decreases to a predetermined extent. The contacts Q are preferably carbon contacts, or other variable - resistance device whose shunting capacity will decrease with increase of lifting power of magnet G. 9c

Fig. 3 simply illustrates how the strength of the field may be varied in the well-known way by varying the number of field-magnet coils in ci rcuit. The field-magnet coil is divided into sections F F' F² F³, &c., to which contacts 95 P are connected, as indicated. Contact-spring g moves over contacts P, and keeps a greater or less number of coils in circuit, according to the necessities of the case. The coils are placed in any circuit, and energized by a cur- ico rentfrom any source. This device may besubstituted for the expedient shown in Fig. 1 for varying the strength of the magnetic field for the armature.

. In Fig. 4 the main circuit D supplies cur- 105 rent to a group of incandescent lamps in multiple arc, and the field-magnet coils are in a derived circuit which passes through an adjustable resistance formed by coils r and contacts P g, governed by armature-lever d. Magnet R is 1 ic in a derived circuit of high resistances around the working - resistances, and its power increases with a diminution in the number of working - resistances, as incandescent lamps calling for a decrease of current to prevent in- 115 jury to those remaining in operation. As the strength of R increases the resistance in the circuit of field-magnet F is increased, cutting down the magnetic field. The commutatorbrushes are simultaneously and automatically 120 adjusted. The parts may obviously be so adjusted or proportioned that the brushes shall be set forward beyond the new neutral point, so as to assist in diminishing the current taken off from the armature^ _I25

In Fig. 5 is illustrated an arrangement in which the strength of the field for the machine that supplies current to circuit D is varied by shifting the brushes of the commutator A’ for an auxiliary machine whose duty is to supply 130 the energizing-current that flows in coils F. The commutator A’ has brushes mounted oq

339,079 an adjustable yoke connected to lever d, so that, as will be obvious, a movement forward of the brushes of A², to decrease the strength of the field-magnet F, will, as in Fig. 1, be accompanied by a simultaneous adjustment of the brushes for commutator B to follow the shifting neutral point.

Figs, hand 7 illustrate how a rotary elec'ric motor may be used to produce the desired adjustments. G indicates a rotary electric motor, of any desired description, geared to a segment upon the adjustable yoke that carries the commutator - brushes. Said motor may be supplied with current from any source, and its movement forward or back may be produced by a current reverser, H, Fig. 7, constructed on the principle well known in telegraphy or in any other well-known manner, and operated by magnet R or other means in such way that when R increases in strength current will flow in one direction through G and cause an adjustment of the current-regulating mechanism in one direction to be produced, while on a reverse movement of the armature for R, due to weakening of R, a current will flow through G in a reverse direction and produce an opposite adjustment. While the magnet R is of the proper or adjusted strength the current-reverser H retains a central position and the motor remains at rest, practically no current flowing through it.

In Fig. 8 we have shown how the armatureshaft or other revolving power-driven shaft may, through the means of reversing mechanism controlled by R, be made to produce the desired movement of the parts. The shaft M²is belted to a wheel, M*, upon a lever, M³, connected to the core of R, and carrying on opposite sides of its fulcrum the wheels n n², gearing with one another and with a wheel, m, rotating with M⁴. Moving respectively with the wheels n n² are the pinions w w², adapted to gear separately with the segment upon the rocker - arm that carries the commutatorbrushes. In oue position of the core of R the upper pinion, w², gears with the segment, thus shifting the adjusting mechanism in one direction. In the opposite position of the core for R the lower pinion, w, engages with the segment and produces an opposite adjustment. In the normal or intermediate position ofthe core neither pinion is in engagement with the segment, aud the commutator - shifting and field-varying devices remain at rest and unaffected.

Instead of adjusting the two single brushes of a commutator, we may shift two sets of brushes, as indicated in Fig. 9. In this case each collecting-brush (positive and negative) is made up of two single brushes connected together electrically and shifted together iu such way as to vary their collecting extent simultaneously with the forward or backward movement.

Other commutator adjustments may be used in place of those described.

We do not limit ourselves in this respect, the invention consisting, broadly, in combining· an adjustable commutator of any kind with means for varying the strength of the 70 magnetic field in such way that an adjustment of the latter shall be accompanied by or effect; directly or indirectly an adjustment of the commutator.

The connection of the adjusting devices may 75 be mechanical or of any desired nature, such that a movement of one shall be accompanied by a movement of the other.

We do not in any respect limit ourselves to the kinds of commutator adjustment de- 80 scribed, nor to the means of varying the magnetic field. Where the adjustment is an automatic one, any controlling magnet or other device that will respond to variations of current may be employed, and may be placed in 85 any desired position or relation to the machine or its circuits, so as to be affected by changes in the current of the machine.