USRE14585E - Power-limiting device - Google Patents

Description

H. DE F. ARNOLD.

1 POWER LIMITING DEVICE. APPLICATION FILED OCT. 30. 1917.

Reissued Jan. 14,1919. 14,585.

0*) re for." Haro/aflZArno/d UNITED STATES PATENT OFFICE. a HAROLD DE PoREsT ARNOLD, P EAsT oRANeE, NEW JE SEY, AssIeNoR, BY MESNE ASSIGNMENTS, To WESTERN ELECTRIC COMPANY, INCORPORATED, A CoRPoRATIoN OF NEW YORK.

POWER-LIMITING DEVICE.

Specification a: Reissued. Letters Patent.- Reigsued J an, 14, 1919.

Original No. 1,200,796, dated October 10, 1916, Serial No. 48,872,111ed September 8, 1915. Application for reissue filed October 30, 1917. Serial No. 199,859. Q

To all whom it may concern Be it known that I, HAROLD DE FoREsT ARN0LD, a citizen of the United States, re-

siding at East Orange, in the county of -Essex and State of New Jersey, have invented certain new and useful Improyements in Power-Limiting Devices, of which I the following is a full, clear, concise, and

exact description.

This invention devices. which may be transferredfrom a source of power to a receiving circuit, that is, to in"- sure that no power in excess of a predetermined amount shall be transferred'from the source of power to the receiving circuit. This object is accomplished by making use of the fact that an electric valve or unilat-. erally conducting resistance, when connected in a circuit containing a battery or other relates to power limiting source of electromotive force, said sourcebeing so poled as to tend to send current in the direction in which the valve will not A pass electricity, acts as an infinite resistance,

to any impressed electromotive force in the I opposite direction to, and less than that of said source. Such a polarized valve may, therefore, be placed as a; shunt around a circuit to be protected, and will then shortcircuit it forvalues of impressed voltage higher than and in the opposite direction to that of the polarizing battery. However, such an arrangement will act only for impressed voltages in onedirection; and to secure protection against high voltages in either direction, it is necessary to add another element in shunt to the circuit to be protected and disposed in the opposite direction. In this case the circuit Wlll be protected against high voltages. in either sense, and thus the current, and hence also the power which may be transferred to a receiving circuit of a given resistance, will be limited to the value which could be transferred by a driving electroniotive force approximately equal to that of either polarizing battery. These unilaterally conducting elements should have low resistances in orderto act as efficient short circuits, and it has been foundthat thermionic devices are circuits this device is intended to be ap- Its objectis to limit the power plied: -By a thermionic element is .meant one consisting of a hot electron-emitting cathode and a cool anode in an evacuated vessel. I The application of this idea to alternating current circuits is shown in the drawing, in which 1 represents a generator or source of alternating current. 2 is one winding of a transformer of which 3 is the other winding, and 4 is one WlIldIIlg of a second transformer, whose other winding 5 is connected to the receiving device 6.

The structure next to signed to limit the amount of power which can be transferred from the source 1 to the receiving device 6.

7 and 8 are thermionic elements, each consisting of an electron-emitting cathode 9 or be described is de-" 11, which maybe heated in the usual mancathode pair vessel. A I

13 is a battery whose negative pole is connected to the anode 10, and 14. another battery whose negative pole is connected to being inclosed in an evacuated batteries 13 and 14, and from the fact that the thermionicelements allow current flow only from anode to cathode, it will be ap-' parent that with no impressed alternating voltage, no current can flow through either element. I Current can flow through element 7, for example, only when the impressed voltage across the winding 3 is high enough to overcome the electromotive force of bat tery 13, in which case current will flowthrough this element from its anode to its cathode. The same remarks apply to element 8', except that in this case the impressed voltage acrossthe winding 3 must be in the opposite direction to cause current to flow through that element.

From the foregoing discussion, it is apparent that neither element will permit the passage of current until the voltage across the transformer winding is larger than that of either battery. When the voltage is less than this, all the power generated by this source is transformed to the receiver 6; but

. when, this alternating voltage rises above that of the battery, some current is shunted around the receiver through the thermionic elements which, therefore, actas a short circuit on-winding 4. If these elements are of low resistance, it will be clear that this short-circuiting effect may be .made very A spark-gap or arrester 15 is preferably connected as shown, its function being simply to provide additional protection to the circuit against extremely high voltages.

While the transformers used in this device are not absolutely essential, still they are desirable because by means of them the impedance relations of the network may he more efficiently-adjusted. For example, if

the thermionic 1 elements have, as usual, a

rather high resistance, "more eflicient operation will' be secured if the transformer 2-3 is adapted to raise the voltage to be applied across the terminals. This stepping f to step the voltage down again to, approximately its original value. said to be arranged in tandem when, as

up of the voltage also insures more effective protection by means of the spark-gap 15. The transformer 4-5 would then be used Transformers are here, the output terminals of one are .con nected directly to the input terminals of the other.

What I claim is:

1. In combination with a source of power and 'a receiving circuit, means for shortcircuiting said circuit when the impulses from said source of power exceed'a predetermined amount, comprising two unilaterallyconducting elements connected in parallel and in opposition with respect to said source, and asource of electromotive force in series with each 'of said elements, said sources of electromotive force tending to send currents in the directions in which said elements will not permit current flow.

2. In combination with a source of power and a receiving circuit, means for shortcircuiting said circuit when the impulses from said source of power'exceed a predetermined amount, comprising a unilaterally conducting element connected. in parallel with said source, and a source of electromotive force in series with said element, said source of electromotive force tending to send current in the direction in which said element will not permit current flow.

3. In combination with a source of power and a receiving circuit, means for shortcircuiting said circuit when thev impulses from said source of power exceed a predetermined amount, comprising two unilater: ally conducting thermionic elements connected in-parallel and in opposition with respect to said source, and a source of elec- I tromotiveforce in ser es Wltheach of said.

elements, said sources of electromotive force tending to send currents in the directions in which said elements will notpermit current flow. y

4. In combination with a source of power and a receiving circuit, means for shortcircuiting said circuit when the impulses from said source of power exceed a predetermined amount, comprising unilaterally conducting thermionic element connected 1n parallel with sa1d source, and a source of electromotive force in series with each of said elements, said source ofelectromotive force tending to sendcurrent in the direction in whichsaid element will not permitcurrent flow.

5. A power-limiting device comprising two transformers connected in tandem, unilaterally conducting thermionic element 5 said elements being oppositely connected across the Winding terminals common to said transformers, and a source of electromotive force in series with each of said "elements and tending to send current in the direction in which said elements will not permit current to flow.

6.,In anele trit system, the combination with a circuit, of means for applying electromotive force thereto, means in said cir- ..cuit for preventing flow of'current through the circuit in one direction at all values of applied electromotive force, and a source of direct electromotive force permitting flow of current through the circuit in the other direction when the applied electromotive.

force equals or exceeds a predetermined value and for preventing flow of current:

whenthe applied electromotive force is be low said limiting value.

'2'. In an electric system, the combination. with a line, of ashunt path therefor,means for applying electromotive force to said line,

and means in said path for preventing ldpw of current through the path 1n one dlrection at all values of applied electromotive force, Y

and for preventing flow of current through the path in the other direction when the electromotive force is below a, predetermined value and for permitting flow of current when the electromotive force equals or ex-l ceeds that value.

8. In an electric system, the combination with a line, of'means for applying electro motive force thereto, and a plurality of shunt paths for said line, each of said paths containing means for preventing flow of cur; rent through the path in onedirection at all values of applied electromotive force and for preventing flow of current through the path in the other direction when the electromotive force is below a definite limiting value, and for permitting flow of'current when the electromotive force equals or exce'e'ds that value.

9. In an'electricsystem, the combination with a line, of a plurality of shunt paths therefor; each of said means for preventing ow of current through the path in one direction at all values ofapplied electromotive force and.

for preventing flow of current through-the path in the other direction when the elec- 'tromotive force is below a definite limiting value and for permitting the flow of current when the electromotlve force equals or exceeds that value, said means in one of said -paths being arranged in; opposition to the corresponding means in another. of said paths, anda transformer in parallel arrangement with said shunt paths.

10. In combination with a source of power and a receiving circuit, a power limiting device comprising two unilaterally conductin thermionic elements connected in. paralle and in opposition, a spark-gap in parallel with sald elements, a source of electromotive forcein series with each of said elements; i

and a receiving circuit, a power-limiting de-' vice eomprisingtwo unilaterally conducting "'elementsconnected in parallelandin oppositionwith respect to'said source,'a source" gaths containing of electromotive force in series with-each of saidelements, said sources of electromati ve force tending to send currents in the d rections in which said elements will not permit current flow, and meansassociated 1 with said device for transmitting current similar in wave form to the current received from said source of power.

i 12. In combination witha source of power and a receiving circuit, a power-limiting device comprising a unilaterally conducting element connected in parallel with said source, a source of electromotive force inseries with said element, said source of electromotive force'tending to send current in the direction in which saidelemen-t willnot per- 'mit current flowyand means associated with said device for transmittingcurrent similar in waveform -to the current; received from said source of ower.

13-. Thecom ination of a source f-power, va 'receivm clrcult and a power-l1m1t1ng device there etween comprising a unilaterally conducting element means. tending to "send current through 'said element in the direction in which current will not flow, and a connectionbetween said device and said cirsaid-source. I

In witness whereof, I hereunto subscribe my name this 6th dayof OctIKber, 1917.

"f. -HARQLD DE Forms ARNOLD. H

cuit whereby the latter transmits impulses similar in wave form to the impulses from

Images