US2084904A - Electric system - Google Patents

Description

June-22, 1937. H. GEISE 2,084,904

ELECTRIC SYSTEM Filed May 19, 1936 Inventor: Hermann Geise.

tbor 'r ey Patented June 22, 1937 ELECTRIC SYSTEM Hermann Geise, Berlin-Karlshorst, Germany, assignor to General Electric Gompany, a corporation of New York Application May 19, 1936, Serial No. 80,632 In Germany May 28, 1935 7 Claims.

My invention relates to electric systems wherein power is transferred between alternating current and direct current circuits by vapor electric apparatus such as mercury arc rectifiers or the like. The invention relates particularly to systems of this character in which the voltage is regulated by means of grids or control electrodes, and the object of the invention is to provide capacitance means so arranged as to eliminate 10 completely in the system. radio frequency oscilable noise in broadcasting radio receivers.

lations tending to disturb radio reception.

It is known that in the operation of mercury arc rectifier systems, disturbing radio frequency oscillations are produced which cause consider- These disturbances are of particularly large magnitude in case the voltage in the rectifier apparatus be regulated with the aid of grids or control electrodes. In the operation of the grid control means the initiation of the successive arcs between the anodes and the cathode is delayed, so that at each initiation of the anode current the voltage rises abruptly and irregularly, with the effect of generating high frequency oscillations which decay comparatively rapidly, to occur again upon the initiation of current at the next succeeding anode. A high, or radio, frequency is thereby produced which is modulated in accordance with the successive initiations of current at the anodes and which, because of the rectification occurring in the broadcasting receiving apparatus, becomes audible as a tone in the latter apparatus. In the case of six-phase rectifiers the disturbing tone has for the most part a frequency of 300 cycles per second and in the case of twelve-phase rectifiers, a frequency of 600 cycles per second.

In order to eliminate the disturbing high frequency oscillations, condensers have been provided heretofore, between the anodes and the cathode in rectifiers without grid control. It has been possible, as a general rule, to obtain satisfactory results by these simple means since the disturbances were mainly due to the fact that the anodes were merely not conducting current quite regularly, and the disturbances, from this cause, were consequently not particularly noticeable. In the case of grid controlled rectifiers, however, this remedial measure is by no means sufficient.

By means'of the circuit organization in ac cordance with my present invention it is possible to diminish the disturbing radio frequency oscillations to such a degree that highly sensitive broadcast long-distance receivers will operate free from these disturbances, even in proximity to rectifier equipment.

The chief feature of this circuit arrangement is that all of the leads and conductors brought into the rectifier tank or metal container are capacitatively interconnected and are furthermore capacitively grounded. This result may be effected for example, in this manner, that the main anodes, grids, and the auxiliary or excita tion anodes are connected through condensers with the cathode or with ground, or with the rectifier casing which is either directly or capacitatively grounded. By the term rectifier casing it is to be here understood that in the case of iron rectifiers the iron tank or shell is meant, and in the case of glass rectifiers, the sheet metal casing or box surrounding the glass bulb.

Furthermore, the cathode must likewise be grounded through a condenser, or must be connected to the directly or capacitatively grounded rectifier casing. What is of particular importance is the manner in which the capacitative connection of the cathode with ground is made. This capacitative connection between cathode and ground should be made directly at the cathode, if possible, and in any case not at a point, along the positive conductor, far away from the cathode.

It has been found, further, to be advantageous to connect the neutral point of the transformer, which supplies the anode voltage, directly with the transformer casing or shell by way of a condenser. The effectiveness of the latter connection will be further enhanced by a capacitative connection of the positive and negative terminals of the rectifier apparatus with ground, and at the point where the conductors connected to these terminals leave the rectifier equipment and pass over, through the building enclosing the apparatus, into the distributing network constituted by cable or air lines.

Since it may happen that radio frequency oscillations pass over from the rectifier apparatus into the three-phase or other alternating current supply network, all of the anode terminals of the transformer may be connected by way of condensers to the transformer casing or shell.

My invention will be better understood from the following description when. considered in connection with the accompanying drawing and its scope will be set forth in the appended claims.

Referring to the drawing, the single figure thereof is a diagrammatic representation of a mercury arc rectifier system in which my invention has been embodied.

In the drawing the numerals I and. 2 designate respectively an alternating current circuit and a direct current circuit between which power is transferred by vapor electric equipment comprising a transformer 3, having a primary 4 and a secondary 5, and a rectifier apparatus 6 including a cathode l, main anodes 8, grids or control electrodes 3, and excitation or auxiliary anodes iii, the cathode, anodes, and grids being enclosed within a casing or container Ii which in the present embodiment of the invention is a metal tank from which the cathode I is insulated by an insulating member !2.

The windings of transformer 3 are enclosed within a metal casing l3 through the walls of which extend conductors i l connecting the phase terminals iii of the transformer secondary 5 with the corresponding anodes 8. The grids 9 are connected through leads iii to suitable grid excitation means il (not shown), and the excitation anodes iii are connected through leads i8 to an excitation transformer l9 supplied from a suitable source Ell (not shown). A positive direct-current conductor 2i, connected to cathode l, and a negative direct-current conductor 22, connected to neutral point 23 of transformer secondary 5, connect the rectifying equipment to the directcurrent circuit 2 through a wall of a building 2 which may enclose the complete equipment.

In accordance with my invention, leads i l con nected to anodes 8, leads l6 connected to grids 9, and leads l8 connected to excitation anodes Ii] are all capacitatively interconnected, and all capacitatively grounded, by condensers 25 and lead 28 between main anode leads 8 and cathode '6, condensers 2'! and lead 28 between grid leads l6 and the cathode, and condensers 2% and leads 3!! between excitation anode leads I8 and the cathode, the cathode i being capacitatively connected to the grounded rectifier casing I I through a con denser 3!.

Further, in accordance with my invention, the neutral point 23 of transformer secondary 5 is capacitatively connected by a condenser 32 and a lead 33 with the grounded transformer casing or shell l3, and the phase terminals l5 of secondary 5 are capacitatively connected by condensers 34 and leads 3'5 with the grounded casing 53. Finally, in accordance with my invention, the two conductors 2! and 22 carrying direct current are capacitatively grounded by condensers 36 mounted closely adjacent to the point at which the latter conductors pass from the enclosing building 24.

My invention has been described herein in a particular embodiment for purposes of illustration. It is to be understood, however, that the invention is susceptible of various changes and modifications and that by the appended claims I intend to cover any such modifications as fall within the true spirit and scope of my invention.

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

1. In an electric system comprising an alternating current circuit, a direct current circuit, and means to transfer power between said circuits including a vapor electric apparatus having a cathode and at least one anode and a control electrode associated with said anode, and a plurality of leads connected respectively to said cathode, said anode and said control electrode, means to eliminate in said system radio frequency oscillations tending to disturb radio reception, said lastnamed means including capacitance means inter-- connecting all of said leads and connecting all of said leads to ground.

2. In an electric system comprising an alternating current circuit, a direct current circuit,

and means to transfer power between said circuits including a vapor electric apparatus having a metal casing enclosing a cathode and a plurality of anodes and control electrodes, and a plurality of leads connected respectively to said cathode, said anodes, and said control electrodes, means to eliminate in said system radio frequency oscillations tending to disturb radio reception, said lastnamed means including capacitance means interconnecting all of said leads and connecting all of said leads to ground.

3. In an electric system comprising an alternating current circuit, a direct current circuit, and means to transfer power between said circuits including a transformer, a metal casing enclosing said transformer, a vapor electric apparatus including a metal casing enclosing a cathode and a plurality of anodes and control electrodes, and a plurality of leads connected respectively to said cathode, said anodes, and said control electrodes, means to eliminate in said system radio frequency oscillations tending to disturb radio reception, said last-named means including capacitance means interconnecting all of said leads and connecting all of said leads to ground and capacitance means connecting the neutral point of said transformer to said transformer casing.

4. In an electric system comprising an alternating current circuit, a direct current circuit, and means to transfer power between said circuits including a vapor electric apparatus having a metal casing enclosing a cathode and a plurality of anodes and control electrodes, and a plurality of leads connected respectively to said cathode, said anodes, and said control electrodes, a building enclosing said apparatus and said leads, and a positive lead and a negative lead connecting said apparatus through said building to said direct current circuit, means to eliminate in said system radio frequency oscillations tending to disturb radio reception, said lastnamed means including capacitance means interconnecting all of said first-named leads and connecting all of said first-named leads to ground,

\ and capacitance means connecting said positive and negative leads to ground closely adjacent the point at which said last-named leads pass from said building.

5. In an electric system comprising an alternating current circuit, a direct current circuit, and means to transfer power between said circuits including a transformer a metal casing enclosing said transformer, a vapor electric apparatus including a metal casing enclosing a cathode and a plurality of anodes and control electrodes, and a plurality of leads connected respectively to said cathode, said anodes, and said control electrodes, a building enclosing said transformer casing and said apparatus and leads, and a positive lead and a negative lead connecting said apparatus through said building to said direct current circuit, means to eliminate in said system radio frequency oscillations tending to disturb radio reception, said last named means including capacitance means interconnecting all of said first-named leads and connecting all of said firstnamed leads to ground, capacitance means connecting the neutral point of said transformer to said transformer casing, and capacitance means connecting said positive and negative leads to ground closely adjacent the point at which said last-named leads pass from said building.

6. In an electric system comprising a direct current circuit, an alternating current circuit,

and means to transfer power between said circuits including a vapor electric apparatus having a metal casing enclosing a cathode and a plurality of anodes and control electrodes, a transformer having a plurality of terminals connected respectively to different ones of said anodes, a metal casing enclosing a transformer, and a plurality of leads connected respectively to said cathode, said anodes, and said control electrodes, means to eliminate in said system radio frequency oscillations tending to disturb radio reception, said last-named means including capacitance means interconnecting all of said leads and connecting all of said leads to ground and capacitance means connecting the neutral point of said transformer and said anode terminals of said transformer to said transformer casing.

'7. In an electric system comprising a direct current circuit, an alternating current circuit, and means to transfer power between said circuits including a vapor electric apparatus having a metal casing enclosing a cathode and a plurality of anodes and control electrodes, a transformer having a plurality of terminals connected respectively to different ones of said anodes, a metal casing enclosing said transformer, a building enclosing said transformer casing and said apparatus and said leads, and a positive lead and a negative lead connecting said apparatus through said building to said direct current circuit, means to eliminate in said system radio frequency oscillations tending to disturb radio reception, said last-named means including capacitance means interconnecting all of said firstnamed leads and connecting all of said first named leads to ground, capacitance means connecting said positive and negative leads to ground closely adjacent the point at which said lastnamed leads pass from said building, and capacitance means connecting the neutral point of said transformer and said anode terminals of said transformer to said transformer casing.

HERMANN GEISE.

Images