US1939458A

US1939458A - Electric valve converting system and excitation apparatus therefor

Info

Publication number: US1939458A
Application number: US677052A
Authority: US
Inventors: Marvin M Morack
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1933-06-22
Filing date: 1933-06-22
Publication date: 1933-12-12
Anticipated expiration: 1950-12-12
Also published as: DE648406C; FR45044E; GB438217A

Description

Dec. 12; #1 933. MQRACK 1,939,458 ELECTRIC vALvz convzn nue SYSTEM AND EXGITATION APPARATUS rasasron Filed'June 22, 1933 Inventor:

Marvin M. Mof'ack.

Patented Dec. 12, 1933 PATENT OFFICE ELECTRIC VALVE CONVERTING SYSTEM AND EXCITATION APPARATUS THERE- FOR Marvin M. Morack, Schenectady. N. Y.,' assignor to General Electric Company, a corporation of New York Application June 22, 1933. Serial No. (av-L052 9 Claims.

My invention relates to electric valve converting systems and more particularly to new and improved apparatus for exciting the control elements of the electric valves of such converting systems.

Heretofore, there have been devised numerous electric valve converting systems for transmitting energy between direct and alternating current circuits, direct current circuits of different voltm ages, or independent alternating current circuits of the same or different frequencies. Many of these systems have included a distributor apparatus effective to render conductive the several electric valves in a predetermined sequence to transfer the current between the several terminals of the load circuit of the system. In many cases, however, it is desirable to eliminate the moving contacts and other disadvantages inherent in a mechanical distributing apparatus. My

invention relates more particularly to an excitation apparatus which may replace the conventional mechanical distributor in the arrangements of the prior art.

It is an object of my invention, therefore, to

5 provide an improved electric valve converting system and an excitation apparatus therefor which will overcome the disadvantages inherent in the mechanical distributor apparatus of the prior art and which will be simple and reliable in operation.

It is another object of my invention to provide an improved electric valve converting system and an excitation apparatus therefor which will render conductive the several electric valves in a predetermined sequence and which will elimicircuits and a device for successively producing variations in the impedances of the devices which,

when the value of their impedance is a minimum.

substantially bypass the sources of control potential from the control elements of the electric valves. For example, the impedance devices may constitute reactance devices having open circuit magnetic paths or cores, in which case there is also provided an inductive member, such as a magnetic vane, in asymmetric inductive relation to the magnetic paths of the several reactance devices. The. inductive member and the reactanoe devices are relatively rotatable and there is provided means for producing relative rotation to successively vary the impedance of the reactance devices and successively energize the control elements of the electric valves to render them conductive. 'It may also be desirable to provide an additional impedance device or reactance device in series with the control circuit of each of the electric valves and to vary successively the impedance of this series reactance alternately with respect to the shunt reactance of each of the control circuits.

For a better understanding of my invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims. The single figure of the drawing illustrates diagrammatically an electric valve converting system for transmitting energy from a single phase alternating current supply circuit to a quarter phase alternating current motor to which is applied my improved valve excitation apparatus.

Referring now more particularly to the drawing, there is illustrated an arrangement for transmitting energy from a single phase alternating current supply circuit 10 to.a quarter phase alternating current motor 11 of the synchronous type comprising armature phase windings 12 and 13 and a rotatable field winding 14. The field winding 14 may be connected in series with the armature winding, as illustrated, in case it is desired to give the motor series characteristics, or in case shunt characteristics are desired the field winding 14 may be separately excited in any well known manner. As illustrated, the field winding 14 is connected between the electrical neutrals of the phase windings l2 and 13, a circuit which 95 carries unidirectional current, as will be explained more fully hereinafter. A variable resistor 15 may be connected across the field Winding 14 to regulate the speed-torque characteristics of the motor, in which case it is preferable also to in- 100 clude a reactor. 16in series with the-parallel connected winding 14 and resistor 15.

The terminals of the armature phase winding 12 are connected to the supply circuit 10 through two groups of similarly connected electric valves 105 17 and 18, and 19 and 20, respectively. Similarly the armature phase winding 13 is connected. to the supply circuit 10 through two groups of electric valves 21 and 22, and 23 and 24, connected to the circuit 10 with a polarity opposite to that 0 of the electric valves 17-20, inc. Each of the electric valves 17-24, inc., is provided with an anode, a cathode and a control electrode and may be of any of the several types well known in the art, although I prefer to use valves of the vapor or gaseous electric discharge type.

In order to render the valves conductive in a predetermined sequence, the control electrodes, or grids, of the pairs of valves 17-18, 1929, etc, are connected to their respective cathodes through current limiting resistors '25, negative bias batteries 26 and secondary windings of

grid transformers

27, 28, 29 and 30, respectively, although in some instances, the negative bias batteries 26 may be satisfactorily omitted. The

' primary windings of the grid transformers 27-30, inc., are excited from the alternating current supply circuit 10 through any suitable phase adjusting means such as an impedance phase'shifting circuit 31 of a typewell known in the art. In order to control the energization of the several gridtransformers 27-30, inc., to render conductive the electric valves in a predetermined sequence, there are connected in parallel. to the primary windings of the transformers 27-30, inc.,

impedance devices illustrated as reactance devices 32-35, inc., respectively, each provided with an an open circuit magnetic'core, although under open magnetic core member. There. are also connected in series with the primary windings of the several transformers 27-30, inc., the several impedance devices illustrated'as reactance devices 36-39, inc., respectively, also each provided with certain operating conditions these last impedance devices may be omitted. An inductive member 40 connected to be rotated by the motomll is mounted in asymmetric inductive relation to the magnetic circuits of the several reactance devices 32-39, inc. The member 40 may be composed of magnetic material and may take the form of a segment of a disk as illustrated, or a segment of a cylinder, or some other mutilated symmetrical form. As indicated in the drawing; the magnetic circuits of the reactance devices 32-39, inc., are symmetrically mounted adjacent the path of rotation of the inductive member 49, the series connected reactance device and the shunt. connected reactance device associated with each grid I transformer being displaced in phase 180 elec- 'trieal degrees referred to the motor, which in the case of the two-pole motor illustrated, is also 180 mechanical degrees. However, this-featuregpf controlling theconductivity of a group ofelectric valves by a distributor mechanism driven by 'a' motor energized through the valves forms no part of my present invention, but is disclosed and broadly claimed in a *copending application of E. F. W. Alexanderson, Serial No. 638,361, filed May 11, 1923, and assigned to the same assignee as-the present application.

The general principles of operation of the above described apparatus for transmitting energy from the alternating current circuit 10 to the motor 11 will be well understood by those skilled in the art, or may be found explained in detail in a copending application of E. F. W. Alexanderson, Serial No. 598,380, filed March 12, 1932, and assigned to the same-assignee as the present application. That application discloses and broadly claims the above-described power circuit, which forms no part of the present invention. Assuming that the motor field winding 14 and the inductive member 40are substantially in the positions illustrated, and that the "phase shifting circuit .31 is so adjusted that the potenthe same time, the magnetic circuits of the reactance devices 32 and 37, 35 and 38 are opened and their impedances are a minimum.. That is, the impedances of the devices .36 and 39 in series with the primary windings of the

transformers

27 and 30 are a maximum, while the impedances of the devices 32 and 35 in parallel with the primary windings of these transformers are a minimum so that these transformers are substantially deenergized and the associated

valves

17 and 18 and 23 and 24 are maintained non-conductive by their respective negative bias batteries 26. At the same time, the impedances of the devices 37 and 38 in series with the primary windings of-the

transformers

28 and 29, respectively, are a minimum while the impedances of the

devices

33 and 34 in parallel with the primary windings of the

transformers

28 and 29 are a maximum so that these transformers are fully energized from the circuit 10 through the impedance phase shifting circuit 31 to render conductive the groups of valves 19 and 20, and 21' and 22. s

The two pairs of

valves

19 and 20, and 21 and 22 comprise a full wave rectifying circuit 'motive force created by the current flowing in the armature windings 12 and 13 will be in such a direction as to cause a torque upon the motor field 14 and initiate a rotation of the motor which,

it will be assumed, is in a counter-clockwise direction.

When the motor 11 has rotated through approximately 90 electrica'l degrees the magnetic vane 40 will have moved to open the magnetic circuits of the reactance devices 33 and 36 and to close the magnetic circuits of the reactance devices 32 and 37, thus energizing the primary winding of the grid'transformer 27 and deenergizing the primary winding of the grid transformer 28. The

electric valves

17 and 18 now become conductive while valves 19 and 20 are rendered nonconductive and current is transferred from the upper to the lower terminal of the armature phase winding 12. The magnetometive force of the motor 11 is thereby advanced through substantially 90 electrical degrees and produces a torque on the motor field 14 to rotate it through an additional 90 degrees. In this manner current is successively commutated between the several terminals of the armature windings 12 and 13 to produce a rotating magnetomotive force and a rotation of the motor 11. The magnetic member 40 is effective to close the magnetic circuit of only those -reaciuamce demagnetic circuits are open to substantially deenergize their associated grid transformers, the series connected devices36-39 inc., may be omitted While I have described what I at present consider the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention, and I, therefore, aim in the appended claims to cover all suchchanges and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent in the United States is:

1. In acontrolled electric valve converting system, apparatus for exciting the control elements of the valves of the system in a predetermined sequence comprising a control circuit for each of said valves including a source of control potential, an impedance device connected in shunt to each of said control circuits, and means for producing successive variations in the impedances of said devices.

2. In a controlled electric valve converting system, apparatus for exciting the control elements of the valves of the system in a predetermined sequence comprising a control circuit for each of said valves including a source of control potential, a reactance device connected in shunt to each of said control circuits and provided with an open magnetic circuit, an inductive member in asymmetric inductive relation to said magnetic circuits, and means for producing relative rotation between said member and said magnetic circuits.

3. In a controlled electric valve converting system, apparatus for exciting the control elements of the valves of the system in a predetermined sequence comprising a control circuit for each of said valves including a source of control potential, a reactance device connected in shunt to each of said control circuits and provided with an open magnetic circuit, a magnetic vane rotatably mounted adjacent the magnetic circuits of said reactance devices, and means for rotating said vane to successively close the magnetic circuits of said reactance devices.

4. In a controlled electric valve converting system, apparatus for exciting the control elements of the-valves or the system in a predetermined sequence comprising a control circuit for each of said valves including a source of control potential, an impedance device connected in shunt toeach of said control circuits, an impedance device connected in series with each of said control circuits, and means for producing successive variations in the impedances of said devices, the variation in the impedances of the series and shunt devices of each control circuit being effected alternately.

5. In a controlled electric valve converting system, apparatus for exciting the control elements of the valves of the system in a predetermined sequence comprising a control circuit for each of said valves including a source of control potential, a reactance device connected in shunt to each of said control circuits, a reactance device connected in series with each of said control circuits, said reactance devices having open magnetic cores, a member in asymmetric inductive relation to said 7 tion of said member.

magnetic cores, and means for producing relative rotation between said member and said cores, the series and shunt connected devices being displaced in phase with respect to the relative rotations, the series and shunt devices of each control circuit being displaced in phase with respect to the rotation ofsaid magnetic member, and means for rotating said magnetic member.

7. In a controlled electric valve converting system for transmitting energy from a supply circuit to a load circuit including an alternating current motor, said system including a plurality of valves interconnecting said supply circuit with the several terminals of said load circuit, apparatus for exciting the control elements of the valves to render said valves conductive in a predetermined sequence comprising a control circuit for each of said valves including a source of control potential, an inductance device connected in shunt to eachv of said control circuits, a rotatable member in asymmetric inductive relation to said inductance devices and connected to be driven by said motor.

8. In a controlled electric valve converting system for transmitting energy from a supply circuit to a load circuit including an alternating current motor, said system including a plurality of valves interconnecting said supply circuit with the several terminals of said load circuit, apparatus for exciting the control elements of the valves to render said valves conductive. in a predetermined sequence comprising a control circuit for each of said valves including a source of control potential, a reactance device connected in shunt to each oi! said control circuits, a reactance device connected in series with each of said control circuits, said reactance devices having open magnetic cores, a magnetic member in asymmetric inductive relation to said magnetic cores and connected to be driven by said motor, the series and shunt connected devices being displaced in phase with respect to the rotation of said magnetic member.

9. In combination, a supply circuit, a load circuit provided with a plurality of terminals, a plurality of electric valves interconnecting said supply circuit and the several terminals of said load circuit, each of said valves being provided with a control element, a control circuit for each oisaid 135 control elements, an impedance device connected in shunt to each of said control circuits, an impedance device connected in series with each of MARVIN M. Monacx.