US1795905A - Torque governor - Google Patents

Description

N. W. STORER TORQUE GOVERNOR March 10, 1931.

Filed Oct. 20, 1927 2 Sheets-Sheet 1 6 2 35 3:9 1 s z 4 5/1 4 M M 3 DU. 4 7 5 4 a A w 8 3 HNVENTOR Norman W Sforer.

ATTORNEY Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE ELECTRIC & MANUFACTURING COIVIPANY,v A CORPORATION OF PENNSYLVANIA TORQUE GOVERNOR Application filed October 20, 1927.

This invention relates generally to governors and more particularly to electrically operated governors for power units.

11 operating busses or railway vehicles propelled by gas-electric or oil-electric power units, when the load is changed, as, for example, when a grade is encountered, the propelling motors tend to maintain the veiicle speed and to draw more current from the enerator, thereby increasing the generator output and the torque on the generator shaft. The load on the engine, accordingly, will be increased and, unless some means is provided for limiting it, the engine will reach its capacity before the flexible electrical app-aratus, and will be reduced in speed and its output correspondingly lowered.

It is, therefore, desirable to provide a governor that may be utilized with gas-electric and oil-electric power units which will func tion over a wide range of engine speeds to limit the torque that may be required from the engine. In order to restrict the loading of an engine, different methods may be utilized and, in gas-electric and oil-electrical power systems, it has been found very satisfactory to control the output of the generator and, therefore, to maintain a substantially constant torque on its drive shaft. Since the invention described hereinafter relates to a device adapted to maintain a substantially constant torque on a generator shaft, it will be rercrred to as a torque governor.

The object of the invention, generally stated, is to provide a torque governor which shall be simple and efficient in operation and readily and economically manufactured.

A more specific object of the invention is to provide means for maintaining the output of an engine of an oil-electric power unit substantially constant for a predetermined engine sneed, yet permi ting wide variations in armature current and voltage.

A further object of the invention is to provide a means for controlling the torque imposed by a generator on an internal-combustion or other engine at a substantially constant value, i respective of the speed, and permitting a wide variation of the generator curr nt and armature amperes.

field Serial No. 22 7,460.

Another object of the invention is to provide for adjusting the torque governor to function at predetermined torque values in response to the current flow in the field and armature windings of a generator.

It is also an object of the invention to provide for adjusting the governor to match its characteristic curve with the characteristic curve of the generator.

The invention, accordingly, as shown in the accompanying drawing, comprises the structural features, combination of elements and arrangement of parts that will be exemplified in the structure hereinafter set forth, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawing, in which;

Figure 1 is a view, partly in section and partly inside elevation, of a torque governor constructed in accordance with this invention,

Fig. 2 is a view, in end elevation, of the torque governor illustrated in Fig. 1,

Fig. 3 is a view, in side elevation, of a ratchet device suitable for a torque governor,

Fig. 4 is a diagram illustrating characteristic curves of generators of a type suitable for use in Diesel-electric-power units,

Fig. 5 is a diagram showing a series of characteristic curves plotted from a test made on a torque governor, to show the effect of varying the spring tension,

Fig. 6 is a diagram illustrating how the torque governor curve may be distorted by rotating the armature to different positions relative to the field windings,

Fig. 7 is a diagram illustrating how the torque governor characteristic curve may be changed to conform to the characteristic curve of a generator by varying the proportionate values of the current flowing in the governor armature and the generator armature, and

Fig. 8 is a diagram showing the governor connected to a generator.

The torque governor illustrated simulates a motor, the windings 22 being stationary,

similar to the field windings of a motor, while the windings 23 are carried by a rotor. Since it is not required, in the functioning of a torque governor of this type, that the rotor rotate through 360 or more, it is sufficient to provide flexible conductors, such as 24:, for connecting the winnings 23 carried by the rotor in the proper circuits. Therefore, on account of the absence of brushesfthe resistance offered by bearing surfaces to the rota tion of the rotor may be reduced to a value that is negligible, and the governor may be made extremely sensitive to variations in torque. V

In order to utilize the governor for the controlling of electrical circuits, a contact-carrying arm 25 is adjustably mounted on a plate 26 which is keyed to the shaft 27 of the rotor provided to carry the windings 23. The plate 26 is provided with a plurality of openings 28 which are arranged in a circle near its periphery. The contact-carrying arm 25 is provided with two groups of openings 29 which are disposed diametrically opposite each other and are positioned to aline with the openings 28 provided in the plate 26.

As will be noted, the angular spacing of the openings 29 in the contact-carrying arm 25 is not the same as the spacing of the openings 28 in the plate 26. Therefore, in order to aline one of the openings29 with an opening 28, it is not required that the plate and contact-carrying arm 25 shall be adjusted relative to one another through an angle equal to the angular spacing of the openings, an adjustment of the plate 26 through an angle equal to a fraction of the angular spacing of the openings being sufiicient. Therefore, provision is made for effecting a micrometer adjustment of the contact-carrying arm relative to the plate 26.

When the contact-carrying arm has been set in any predetermined position relative to the plate 26, it may be retained in that posi-- tion by any suitable means, such as screws 30. In this construction, when one of the openings 29 is alined with one of the openings 28, an opening of he diametrically opposite group of openings 29 will be alined with another opening 28. However, this is a matter of design and not essential.

In the manner described above, the contact-carrying arm 25 may be set in different predetermined posit-ions relative to the plate 26 and to the windings 23 carried by the rotor, which herienafter will be referred to as the rotor. A contact membe 31 is mounted on the contact-carrying arm 25.

As best shown in Fig. 2, the contact menber 31 is disposed between two adjustably mounted contact screws 32 and 33 which are carried by a bracket 34 that is mounted on the governor frame. In this particular construction, the contact member 31 is disposed to engage only the contact screw 33, an insulating block 35 being interposed between the contact member 31 and the contact screw 32. In this construction, the contact screw is utilized as a stop to limit the angular movement of the arm 25.

Ihe contact member 31 may be connected in any electrical circuit by means of the screw 36, while any conductor may be directly connected to the screw 33. Since the contact screws 32 and 33 are adjustable, provision is' made to change, as desired, the limits of movement of the contact member In order to electrically connect the conductors 24' into a circuit, terminal posts 37 are provided. The field of the governor, or the windings 22, may be electrically connected to any circuit by means of the terminal posts It will be readily understood that any desired number of terminal posts 37 and 38, with the desired number of turns of the rotor or field windings connected bemay be utilized for adapting to diif rent service conditions.

the governor must be carefully ZLAjUSId such features will have their limitations, and it will generally be required that the governor shall be designed to meet the particular conditions under which it is to be utilized for controlling the torque on ti o engine.

Leferring again to Fig. 2, a tensioning lever 39 is shown rotatably mounted on a laterally extending rim 40 provided on the governor frame. Tension springs ll are connectedbetween the tensioning lever 39 and the contact-carrying arm 25. In order to retain the tensioning lever 39 in different positions, a ratchet a2 is provided on the governor frame to engage a dog disposed on the under side of the lever handle 43.

The governor may be connected in a generator circuit in the manner shown and described in my co-pending application hereinbefore referred to. However, in order that this application may be substantially complete in itself, the connection of the governor in a generator circuit is shown in Fig. 7.

As will be observee, the governor field winning is connected in series with the genera'tor field winding, while the governor armature is disposed to shunt the interpole field winding of the generator. However, any other suitable connections between the generator and torque governor may be made.

The characteristic curve of the torque govenor' will depend on its structural and electrical features. However, by varying the current flowing in the governor windings, making the proper adjustments of the rotor and tensioning lever 43, the characteristic curve of the governor may be made to coincide with or match substantially any selected generator curve.

In order to explain clearly the manner of the gover u flower sin ce i speed of 750 R. P. M.

adjusting a governor to match its character istic curve with that of a generator, a set of curves is submitted showing a plurality of generator curves and the effect on the governor curve of varying the current in the governor windings and of making adjustments of the governor parts.

The typical generator curves illustrated in Fig. lwere obtained from two generators of differenttypes by plotting values of field current and armature current corresponding to constant torque. The curve designated S was obtained from a compensated generator, while the curve R is a characteristic curve of a 210 kw. generator having a rated Referring to Fig. 5, two torque-governor characteristic curves, which extend substantially parallel to each other, are shown. These curves were obtained by plotting the iield amperes on the values of generator armature current at which the governor functioned.

In making the test to obtain the current values from which the curve 4a was obtained, :he torque-governor armature windings were connected in shunt with the interpole field windings which normally carry the full current of the generator-armature windings and adjusted to carry 1% of the generator-arma ture amperes, while the torque-governor field windings and generator field windings were connected in series. Further, the tensioning lever 43 was set to give maximum spring ten sion.

Each point on the curve 44 was determined by applying power to the governor and observing values of field and armature current at which the governor would function. The curve 45 was obtained in the same way as was curve 44:, with the exception that the tension of the spring 41 was weakened. The result of weanening the spring tension, as shown in Fig. 5, was to effect a shifting of the curve along an axis extending at an angle of 45 from the horizontal.

Therefore, it will be seen that, when it is desired to change the torque-governor curve to match a particular generator curve, it may be moved substantially parallel to itself by adjusting the tension of the governor springs 41 to reduce or increase the output of the generator, and, consequently, of the internalcombustion engine.

The curve shown in Fig. 6 illustrates how the characteristic torque governor may be changed by setting the governor armature in different positions relative to the field windings. In making the test, a neutral position for the governor armature is assumed, and the values of the field and armature current at which the governor functions were plotted, giving the curve 46.

ssurning now that the governor armature is rotated 10 clockwise or in the forward direction, a magnetizing effect is produced that is due to the armature current, which permits the functioning of the governor on the flow of a smaller amount of current in the field winding than is required when the governor armature stands in the neutral position. In fact, it has been found that the governor will operate in response to h avy armature currents and without any field current. Accord ingly, the curve 47, plotted from the field and armature current values obtained with the governor armature set 10 forward from neutral, is distorted downwardly.

When the governor armature is rotated backwardly or counter-cloclnvise with respect to the field to give it a back-lead relative to the assumed neutral position, a demagnetiziug action is effected by the armature current. Therefore, before the governor functions, it is required that the current flowing in the field windings be increased above the values required to etiiec't an operation of the governor when it stands in its neutral p sition.

The curve was obtained from the current values read when the governor armature was set counter-clockwise 15.

The our s 50 and 51 were obtained by varying t e proportionate value of the cur rents flow in the governor armature and the generator armature. As illustrated in Fig. 8, the torque-governor armature 52 is connected to shunt the interpole winding 53 the generator 54:, and a rheostat 55 is provided for varying the proportionate values of the current flowing in the torque-governor armature and in the generator armature.

Assuming now that the rheostat 55 is adusted to permit 1% of the generator current to flow through the torquegovernor armature, by plotting the fieid-current amperes on the generator-arma'ure amperes, the curve 49 is obtained. If the amount of current fiowing in the torque-governor armature is decreased, the curve will be distorted upwardly, as shown by the curve 50, while, if the percentage of currentfiowing in the torque go ernor armature is increased, the curve is dis torted downwardly, see curve 51). The current values for plotting the curves 50 and 51 were obtained when the current fiowing in the torquegovernor armature was made 8% and 1.2%, respectively, of the current flowing in the generator armature.

It will, therefore, be evident that the torque governor may be adjusted to meet different operating conditions in three ways; i. e., by rotating the rotor clockwise or counter-clockwise relative to the field windings by varying the ratio between the current flowing in the generator armature and the torque-governor armature, and by shifting the lever 43 to vary the tension of the springs l1. Further, if

necessary, the torque governor may be specially designed to adapt it to be utilized with selected types or generators.

Since numerous changes may be made in the above-described construction, and differant embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a torque governor provided with field windings and a rotatable armature, in combination, a switch carried by the armature, resilient means disposed to bias the armature in a predetermined angular direction, said switchbeing disposed to be closed by the biasing force delivered through the armature and means for adjusting said switch relative to the armature.

2. In a torque governor provided with a field winding and a rotatable armature winding, in combination, a contact member carried by the armature and Vernier adjusting device interposed between the contact member and the armature.

3. In a torque governor provided with a field winding and a rotatable armature winding, in combination, a contact member carried by the armature winding, a Vernier adjustment interposed between the contact member and armature winding and resilient means for biasing the armature to a predetermined position said position being determined by the position of the contact member relative to the armature windin 4:. In a torque governor provided with field and armature windings, in combination, means for biasing the armature to different predetermined relative positions with respect to the field windings, and terminal connectors connected in the field and armature windings to provide sections that may be connected in any circuit.

5. In a torque governor provided with a field winding and a rotatable armature, in combination, a contact member carried by the armature and a stationary contact member disposed to receive the armature contact member, means for biasing the contact members into engagement and means for connecting predetermined sections or" the field and armature windings to carry electric currents to adapt the governor to different operating conditions.

6. In a torque governor provided with a field winding and a rotatable armature, in combination, means for connecting different sections of the field and armature windings to carry electric currents to adapt the governor to different operating conditions, a contact member adjustably mounted on the armature, a stationary contact member to stop the armature in difi'erent predetermined positions, resilient means for biasing the contactmembers into engagement and means for varying the force exerted by said resilient means to change the operating char acteristics of the governor.

7. In a torque governor provided with relatively movable field and armature windings, in combination, a switch disposed to be actuated upon the relative movement of the governor windings, means disposed to bias the armature in a predetermined angular direction, a switch disposed to be actuated upon movement of the armature in a predetermined direction and means for adjusting said switch to adapt itto diil erent relative movements of the governor windings.

8. In a torque governor, in combination,

field and armature windings, said armature being rotatably mounted, a contact member adjustably mounted on the armature, a stationary contact member disposed to receive he armature contact member and resilient s for biasing the armature in a predetermined direction to set the contact members in predetermined relative positions.

9. In a torque governor provided with field and armature windings, in combination, means for setting the armature windings in different predetermined positions relative to the field windin s, resilient means for biasing the armature windings to said predetermined positions, a switch disposed to'be actuated upon the relative movement of the field armature windings, the switch being biased to its closed position by said resilient means, and means for limiting the movement of the switch.

10. In a torque governor provided with relatively movable field and armature wind ings, in combination, means for setting the armature windings in different predetermined positions relative" to the field windings, and resilient means for biasing the armature in said predetermined positions, said resilient biasing means being adjustable to vary the biasing force, said armaturesetting means and said means for varying the biasing force being cooperative to change the operating characterstics of the governor, thereby to change the characteristic curve obtained by plotting values of field current on armature current.

11. In a torque governor provided with relatively movable field and'armature windings, in combination,means for setting the armature windings in difierent predetermined positions relative to the field windings, resilient means for biasing the armature windings to said predetermined positions, said resilient means being adjustable to vary the biasing force and means for controlling the current flowing in the field and armature windings of the governor, said means for setting the armature and field windings in different relative positions, the

means for varying the biasing force and the means for controlling the current in the field and armature windings being cooperative to change the operating characteristics of the governor, thereby to change the character istic curve of the governor obtained by plotting values of field current on armature current.

12. In combination, a generator provided with field and armature windings, a torque governor provided with relatively movable field and armature windings, the field and armature windings of the torque governor being connected in series with the field and armature windings of the generator, respectively, means for setting the armature windings and the torque governor in difierent positions relative to the field windings, resilient means for biasing the armature windings of the torque governor to said predetermined positions, said resilient means being adjustable to vary the biasing force, means for controlling the ratio of current flowing in the field and armature windings of the torque governor in different predetermined positions relative to the field windings, the means for varying the biasing force and the means for varying the ratio of the current in the field and armature windings being cooperativ to 39 change the characteristic curve of the torque governor obtained by plotting field amperes on armature amperes in order to match the characteristic curve of the generator.

13. In a torque governor provided wit-h relatively movable field and armature windings, in combination, resilient means for biasing the armature and field windings to different predetermined relative positions, said resilient means being adjustable to vary 40 the biasing force, and means for controlling the ratio of current in the field and armature windings, said means for varying the biasing force and means for controlling the ratio of current being cooperative to change the operating characteristics of the torque governor to change the characteristic curve obtained by plotting values of field current on armature current.

14. In a torque governor, in combination, stationary field windings, a rotor disposed for movement relative to the field windings,

armature windings provided on the rotor, a

switching member carried by the rotor,

means cooperative with the switching member to to limit the angular movement of the rotor in one direction and means for setting the switching member in difierent predetermined angular positions relative to the rotor to change the characteristic curve of the gov- CG ernor obtained by plotting field current on armature current.

In testimony whereof, I have hereunto subscribed my name this 8th day of October, 1927.

NORMAN WV. STORER.

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