US2099561A

US2099561A - Electric valve converting apparatus

Info

Publication number: US2099561A
Application number: US699758A
Authority: US
Inventors: Rolland C Griffith; Burnice D Bedford
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1933-11-25
Filing date: 1933-11-25
Publication date: 1937-11-16
Anticipated expiration: 1954-11-16

Description

1937- I R. c. GRIFFITH ET AL 2,099,561

ELECTRIC VALVE CONVERTING APPARATUS Original Filed Nov. 25, 1953 Invent 0P5:

ROI land C. Griffith, Burnice D. ge dford.

Their" Attorney.

can

arc. fhowever, has not been directly applicable to a system employing a plurality of vapor electric apparatus with independent cathode potentials. "Our present invention, while of a general application, is primarily directed to such a system "employing a plurality of single anode vapor electric apparatus with independent cathode poten- *tials. .It is an object of our invention, therefore,fto 40 verting system in which the operation of the "apparatus will be controlled in response to *the {occurrence of actual or incipient reverse ,arcs within.the apparatus. v It" is another object of our invention to provide an improved vapor electric valve converting sys- Patent ed Nov. 16, 1937 UNITED STATES PATENT OFFICE 2,099,561 ELECTRIC VALVE CONVERTINGAPPARATUS Rolland C. Griffith and Burnice 1).;Bedfoid, Schenectady, N. Y., assignors to Gcneral Electric Company, a corporatioriof New York Application November 25,1933; Serial No; 699,758

Renewed June-:12, 1937 reverse arcs generally appear as arcs between the several anodes of a multi-anode vapor electric apparatus; or as a reverse are from the cathode tothe anode of a single-anode vapor electric apparatus operating in a system utilizfing'a'number of such apparatus -Ifrsuch reverse '-arcs within the vapor electric apparatus area;-

lowed to-persist they may cause serious damage,

notonly-to'the apparatus itself, but to the 'tem and other apparatus with which the;va por electric apparatus is associated. It'hasj heretoffore been proposed to control the -ope'ratio'n of such vapor electric apparatus of the metal tank type by providing theanodes of the apparatus with associated control .grids and controlling the potential of these grids in response to thereversal of the potential between the cathode and the metal tank, which, it has been discovered, is

an indication of an actual or incipient reverse This arrangement as previously devised,

provide an improved vapor electric valve-contem in which the control electrodes associated "with the several anodes of the converting appa- Iratus are normally excited with a control poten- "and in which this controlling potential is suppressed in response to the occurrence of incipient or actual reverse arcs within the apparatus. 1

tial to control the conductivity of the apparatus In accordance with one embodiment of ourfin- -vention', the several anodes of a vapor electric anparatus of a valve converting system are pro- 'vided with associated control electrodes upon which are impressed control potentials for normally controlling the conductivity of the apparatus' Also enclosed within the separate container of each vapor electric apparatus is an auxiliary conductive electrode, or member, in contact with the ionized vapor. In the case of an apparatus with a metallic container, this member may comprise the container itself. This conductive member isconnected to its respective cathode through a unilaterally conductive device and an insulating transformer. The secondary windings of the several insulating transformers are connected to the common control circuit of an auxiliar'y electric-valve which is connected to modify the-magnetization; as for example, by saturation,

of the main' control transformer. In this manner, the" occurrence of a reverse are within any of the vaporelectric apparatus reverses the poj tential between its auxiliary conductive member and its cathode, sending an impulse of current through its associated transformer which is effective to render conductive the'auxiliary electric valve to saturatethe main control transformers and thus to remove the excitation and render the main valve converting apparatus nonconductive. For a-bette'r understanding of our invention, together with other and further objects thereof, reference is had to the following description taken 'in connection with the accompanying drawing, '1 andits scope will be pointed out in the appended "claims." The'singlefigure of the drawing is a diagrammatic representation of our invention as applied to the protection from reverse arcs of a yapor electric 'valve converting system for transmitting energy from a three phase alternating current supply circuit to a direct current load circuit.

1"Referring now more particularly to the drawing, there'is'shown a vapor electric valve converting systemembodying our invention for transmitting energy from a three phase alternat- A= current smoothing reactor I1 is vided with an anode, a cathode, a control grid, and an auxiliary conductive member or electrode [8 in contact with the ionized vapor of the valve, although, as stated above, in case the valve is contained within a metallic envelope, the envelope itself may constitute the auxiliary conductive member. The control electrodes of the electric valves l4, l5 and I6 are connected to their common cathode circuit through protective resistors 19, negative bias batteries 20, and the secondary windings of the main control transformers 2|, 22 and 23, respectively. The main control transformers 2l-23, inc., may be of any desired type, although we prefer to use selfsaturating transformers, so that the potentials induced in the secondary windings are of peaked wave form. The primary windings of these transformers are energized from the appropriate phases of the supply circuit I through any suitable phase adjusting mechanism, such as a rotary phase shifting transformer 24.

In order to render ineffective the normal excitation circuit for the control electrodes of the several electric valves under reverse arc conditions, the auxiliary conductive members [8 of the electric valves l4-l5-I6 are connected to their respective cathodes through unilaterally conductive devices, such as contact rectifiers 25-26-21 and the primary windings of auxiliary control transformers 28-29-30, respectively. The secondary windings of the transformers 28-29-30 are connected in parallel through protective resistors 3i and to the control electrode of an auxiliary electric valve 32. This common control circuit may include also a biasing battery 33, if desired. Each of the main control transformers 2 l-22-23 is provided with an auxiliary saturating winding 34, and these windings are connected to be excited in series from a source of current, such as a battery 35, through the auxiliary electric valve 32. Switching means shown as a manually operated switch 36 may be provided to interrupt the current in the saturating windings 34 and restore the operation of the system.

The general principles of operation of the above described rectifying system will be well understood by those skilled in the art, so that a detailed description is believed to be unnecessary. It will also be well understood that the average energy supplied to the load circuit ll may be controlled by adjusting the rotary phase shifting transformer 24 to adjust the phase relationship between the alternating potentials impressed upon the control electrodes of the electric valves I4-I5-l6 and the anode potentials of these valves. If it be assumed, for example, that at any particular instant the electric valve I is operating normally as a rectifying valve, and electric valve l4 fails, so that a reverse arc tends to flow from its cathode to its anode, it will be seen that two of the phases of the network l3 tend to become short circuited through the electric valves l5 and M in series. As stated above, it has been demonstrated that under such condi tions, the potential of the auxiliary conductive electrode l8 with respect to the cathode of the electrode valve l4 reverses in potential from a normally positive value to a negative value. This reversal may take place upon the occurrence of an incipient are back which may actually never develop into a power arc. The unilaterally conductive devices 25-26-21 are so connected that, with normal potential impressed upon the auxiliary electrodes l8, no current flows in the primary windings of the auxiliary control transformers 28-29-30. Upon the reversal of potential between the electrode l3 of the valve I4 and its cathode, however, a current impulse is sent through the primary winding of the transformer 28 which impresses a positive impulse on the auxiliary electric valve 32 to render this valve conductive. In this manner, the source of current 35 is effective to energize the saturating windings 34 of the main control transformers 2l-22-23 to completely suppress the potentials normally induced in the secondary windings of these transformers. The result is, that the negative bias batteries in the control circuits of the electric valves l4-l5-l6 are effective to render these valves nonconductive. Valve 32 is preferably of the vapor electric discharge type so that it will maintain the transformers 2l-22-23 in a saturated condition until the circuit of their saturating windings is opened by the switch 35. In this way an incipient or actual reverse arc in any of the several electric valves i4-l5-l6 is effective to interrupt the operation of the system and thus prevent damage to the system and its associated apparatus.

While we have described What we at present consider the preferred embodiment of our invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from our invention, and we, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination with a vapor electric valve converting apparatus comprising an anode, a cathode, a control electrode, and a conductive member in contact with the ionized vapor of the apparatus, a saturable control transformer for exciting said control electrode to control the energy transmitted by said apparatus, and means responsive to the potential between said conductive member and said cathode for varying the saturation of said transformer to control the energy transmitted by said apparatus.

2. In combination with a vapor electric valve converting apparatus comprising an anode, a cathode, a control electrode, and a conductive member in contact with the ionized vapor of the apparatus, a saturable control transformer for exciting said control electrode to control the energy transmitted by said apparatus, and means responsive to a reversal of the potential between said conductive member and said cathode for saturating said control transformer to suppress the excitation to said control electrode and to render said valve apparatus nonconductive.

3. In combination with a vapor electric valve converting apparatus comprising an anode, a cathode, a control electrode, and a conductive member in contact with the ionized vapor of the apparatus, an excitation circuit for said control electrode including a source of negative bias potential, a self saturatingtransformer provided. with a winding included in said control circuit to impress upon said control electrode an alternating potential of peaked wave form for normally controlling the conductivity of said apparatus, and means responsive to a reversal of the potential between said conductive member and said cathode upon the occurrence of a reverse arc in said apparatus for saturating said transformer to suppress the excitation to said control electrode and to render said apparatus nonconductive.

4. In combination with a vapor electric valve converting apparatus comprising an anode, a cathode, a control electrode, and a conductive member in contact with the ionized vapor of the apparatus, a control transformer for exciting said control electrode to control the energy transmitted by said apparatus, a saturating winding for said transformer, means including an auxiliary electric valve for controlling energization of said saturating winding, and means responsive to the potential between said conductive member and said cathode for controlling the conductivity of said auxiliary valve.

5. In combination with a vapor electric valve converting apparatus comprising an anode, a cathode, a control electrode, and a conductive member in contact with the ionized vapor of the apparatus, a control transformer for exciting said control electrode to control the energy transmitted by said apparatus, a saturating Winding for said transformer, an energizing circuit for said saturating winding including an auxiliary electric valve, and means responsive to a reversal of potential between said conductive member and said cathode upon the occurrence of a reverse arc in said apparatus for rendering conductive said auxiliary electric valve, whereby said vapor electric apparatus is rendered nonconductive.

6. In an electric valve converting system, a plurality of electric valves each provided with an anode, a cathode, a control electrode, and a conductive member in contact with the ionized vapor of the apparatus, control transformer apparatus connected to excite the control electrodes of'said valves to normally control their conductivity, an auxiliary control circuit interconnecting the conductive member and the cathode of each of said valves, and a circuit for saturating said control apparatus including an auxiliary electric valve, said auxiliary electric valve being connected to respond to the reversal of potential in anyof said control circuits.

7. In an electric valve converting system, a plurality of electric valves each provided with an anode, a cathode, a control electrode, and a conductive member in contact with the ionized vapor of the apparatus, an exciting circuit for the control electrode of each of said valves, each including a saturable transformer for normally controlling the conductivity of its associated valve, an auxiliary control circuit interconnecting the conductive member and the cathode of each of said valves including a unilaterally conductive device, and a circuit for saturating said transformers including an auxiliary electric valve, said auxiliary electric valve being connected to be excited by the flow of current in any of said auxiliary control circuits.

ROLLAND C. GRIFFITH. BURNICE D. BEDFORD.