US2003011A - Treating-out transformer - Google Patents

Description

May 28, 1935. H. A. ROSE TREATING-OUT TRANSFORMER Filed Dec. 21, 1952 2 Sheets-Sheet 1 Gazhode Amperes INVENTOR Herbert A. Rose.

ATTORNEY May 28, 1935. H. A. RosE; 2,003,011

TREATING-OUT TRANSFORMER Filed Dec. 21, 1952 2 Sheets-Sheet 2 BYgi Z ATTORNEY Patented May 28, 1935.

UNITED STATES PATENT A oFFiCE l j Westinghouse Electric- & Manufacturing Company, East Pittsburgh, Pa.,'a corporation of Pennsylvania.

Application December '21, .1932, Serial No; 548,204 3 Claims. ((1175- 363) My invention relatesto a treating-out transformer and particularly to a transformerhaving an auxiliary winding for initiating the currentcarrying or main arcs in a rectifier being treated.

In treating-out rectifiers, it is desirable to provide sufficient voltage to supply the arc drop without any appreciableremainder in order to' perform the operation economically. However, in treating-out rectifiers, it is frequently found that a potential substantially equal to the arc drop is not suflicient to initiate a'rectifying are even in the presence of a continuously operating keep-alive arc. According to my invention, the treating out transformer is provided with an auxiliary winding capable of producing a voltage sufliciently in excess of thearc voltage to fiash? the rectifier and start a rectifying arc, after which the rectifier may be switched back to the treating out winding for providing the normal treating out current. Preferably the starting 7 winding will be connected to only a portion of the anodes while the remaining anodes will remain connected to the treating-out winding;

Suitable switching equipment may be provided for changing the connection to thetreating .out winding or the starting winding at the will of the operator. In order to provide an economical de sign, it is desirable that the starting winding be provided with a steep regulation characteristic suiiicient to reduce its voltage substantially. to that of the treating-out winding when the starting winding iscarrying current.

I have found that this auxiliary winding may be associated with the iron of the treating'out transformer or in some cases it may most advantageously be constructed as a separate transformer and then assembled as aunit with the main treating-out transformer.

Otherobjects and advantages will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which 1 Figure-1 is a schematic view of a treating-out system embodying my invention.

Fig. 2 is a similar view showing a modification.

Fig. 3 is a graphic illustration of the potentials applied by the treating-out transformer, and

Fig. 4 is a View similar to Fig. 2 showing a modification according to my invention.

The treating-out transformer, according to my invention, comprises a suitable polyphase primary l adapted to be connected to the high tension line 2 by a suitable circuit breaker 3. As shown, the primary is connected in delta, each leg of the delta being comprised .of two winding groups and suitable variable connectors 4 be-,

tween'ithe groups for changing the numberof turns 'in'the delta windings, and consequently th voltage of the treating-out winding. Y

The secondary winding consistsofa star connected group 6 adapted to -be connected to the anodes I of the rectifier 8 undergoing treatment. A suitable keep-alive source I0 is provided for maintaining a keep-alive arc; in the, rectifier 8. A'suitablecurrent limiting resistor 12 .is con nected between the mid-point of the secondary winding 6 and the rectifier cathode l5. Preferably, the primary I is so adjustedthat the voltage of the star secondary 6 is sufiicient to supply. the desired current to the anodes 1 at a voltage substantially equal the arc drop voltage of the rectifier. This prevents wasting of any material quantity of energy, in the regulating resistor 12.

A suitable high voltage winding 20; preferably single phase, is associated with'the primary 1 in such a manner that the terminal voltages of the auxiliary winding 20 may be connected to one or more of the anodes I of the rectifier 8. Suitable switches ,Zl may be provided for connecting the selected anodes either to the auxiliary starting winding 20 or to the main treating-out winding 6. V

A suitable connection 22 is provided betweenthe mid-point of the treating-out winding 6, and the starting winding 20. The treat-out winding 6 may have a substantially flat voltage characteristic on the different taps of the primary, as shown by the'characteristic curves 252621 of Fig. 3. However, thestarting winding 20 should have a comparatively steep or drooping characteristic, as

shown by :the characteristiccurve 30 in Fig. 3.

. Inthe operation of ,my device, the keep-alive electrode 32 is energized by a, suitable auxiliary rectifier I0, preferably connected by a suitable anodes 1 will then'be disconnected from the treatout winding 6 and connected to the starting winding 20. The high potential of this winding insures the formation of arcs to these anodes which readily causes pick up of the remaining anodes connected to the treat-out winding '6. After the anodes connected to the treat-out winding have picked up, the switches 2| may be operated to connect the anodes originally connected to the starting winding to the treat-out winding. 7

The modification shown in Fig. 2 differs from that of Fig. 1 only in that the starting winding 40 is wound on a separate iron core and provided with its own primarywi'nding 42.. In some cases, it may be desirable to construct the starting winding for continuous operation and to connect it permanently to the starter anodes as shown at 45. The switch 2| between the anode lead and the treat-out transformer is used for connecting the anodes to the treat-out winding 6 tojjcarry full current without disconnecting the same from the starting winding. Theexceedinglsteep regulation 30 of the flashing winding will cause the' current to divide between the starting winding and the treat-out winding insuch proportion that the majority of the treat-out current will-be supplied by the treat out winding 6.

I he current supplied by theauxiliary winding 20 maybe regulated if desirdby a resistor arrangement 35 in the neutral connection{22;

A further modification(see-Fig} 4) consists in utilizing the tank proper as the starting anode. When the tank is used as thestarting anode only one end of the auxiliary winding 50 can beconnected to the tank while the other end must be attached to the cathode,'thus the auxiliary wind-' ing 50 carries only unidirectional current. -In order to offset the saturating effect of the direct current in the secondary 50 the core 5| is provided with a suitable air gap 52.

While I have shown and described specific modifications of my'invent'ion, it is apparent that changes and modifications can be made therein without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are embodied in the accompanying claims or asmay be necessitated by theprior art.

I claim as my invention:

1. A treating out-transformer'for a vapor electric device comprising a primary winding, a polyphase secondary winding adapted for connection to the anodes of the vapor electric device, said secondary 'windinghaving a terminal voltage substantially equal to the arc drop of the device, an auxiliary winding in said transformer, said auxiliary winding normally-havinga "higher voltage than said secondary winding, means for selectively connecting two of the anodes'to either said secondary or said auxiliary winding, and a common return connection to said secondary winding and said auxiliary winding.

2. A treating out transformer for a vaporelectric device comprising a primary winding, a polyphas e secondary winding adapted forconnection to the anodes of the vapor electric device, an aux iliary windingin said transformer, said auxiliary winding normally having a higher voltage'than said secondary winding, meansfor selectively connecting two of the anodes to 'either said secondary or said auxiliary winding, a neutral tap in both said secondary and said auxiliary winding and a resistor connectedbetween: said neutral taps for limiting the current in said auxiliary winding.

3. In a rectifier system, a multi-ancde rectifier, a transformer for treating out said rectifier er than the arcdrop of the rectifier and means for connecting one of said anodes at will to said main winding or said auxiliary winding.

la-Ina treating out device for a rectifierhaving 'aplu'rality of anodes, a polyphase transformer, phase windings in said transformer for attachment to said anbdes, voltage adjusting taps in said transformer for adjusting the voltage appliedtosaid anodes to avalue substantially equal to the arcdrop in the rectifier, an auxiliary winding associated with said transformer, said auxiliary'winding havinga steep regulation characteristic and means for connecting at least one of said anodes either to'said phase windings or to said auxiliary winding. v

5. A treating out transformer for. a mercury arc rectifier comprising a polyphase secondary having a neutral tap, means for connecting the secondary, to the rectifier anodes, a tertiary winding in phasefwith one ofthe phases of the secondary winding, said'tertiary having a. steep regulation characteristic and means operable to disconnect an anode from the secondary and connect itto .the tertiary.

6. A treating-out transformer for a vapor-electric device comprising, a winding adapted for connection to an alternating current line, a winding adapted for supplying to the anodes of a vapor-electric device a potential of the order of the arc drop in. the device, an auxiliary winding in said transformer adapted forconnection to the anodes of the vapor electric device and means for limiting the current in said auxiliary winding.

'7. A system for supplying treating-out current to avapon-electric device comprising a winding adapted for supplying treat-out voltage to the anodes of the device being treated, a winding for producing a voltage in excesss of the treatingout voltage, a switch for connecting at least one of the anodes of the device to either said first or said second winding and means for limiting the current supplied by said second mentioned winding.

8. A'system for supplying treating-out current to a vapor-electric device comprising a winding adapted for connection to the anodes of the device being treated, a winding for producing a voltage in excess of the treating-out voltage, a switch-for'connecting at least one of the anodes of the device'to either said first or said second winding and resistance means for limiting the currentsupplied by said second mentioned winding.

HERBERT A. ROSE.

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