US2449986A - Manufacture of dry contact rectifiers - Google Patents

Manufacture of dry contact rectifiers Download PDF

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Publication number
US2449986A
US2449986A US500438A US50043843A US2449986A US 2449986 A US2449986 A US 2449986A US 500438 A US500438 A US 500438A US 50043843 A US50043843 A US 50043843A US 2449986 A US2449986 A US 2449986A
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United States
Prior art keywords
rectifier
rectifiers
resistance
discs
manufacture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US500438A
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English (en)
Inventor
Grace Bertram Barnett
Ellison Leslie James
Leman Hugh Spence
Leng Charles William
Bridge Arthur Samuel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STC PLC
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Standard Telephone and Cables PLC
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Filing date
Publication date
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
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Publication of US2449986A publication Critical patent/US2449986A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D48/00—Individual devices not covered by groups H10D1/00 - H10D44/00
    • H10D48/01—Manufacture or treatment
    • H10D48/04—Manufacture or treatment of devices having bodies comprising selenium or tellurium in uncombined form
    • H10D48/048—Treatment of the complete device, e.g. by electroforming to form a barrier

Definitions

  • the voltage finally applied is about 20 volts.
  • the electrical treatment consists in applying a direct current source to a plurality of circuits in parallel, each circuit consisting of a. single rectifier and an individual resistance.
  • Rectifiers as initially manufactured differ in their rectifyin properties and in treating a large number of rectifiers in parallel, initially poor rectifiers shunt the initially good rectifiers and so prevent the current necessary to build up a reverse resistance from passing through the latter.
  • the time of electrical treatment can be reduced to about one hour and a very high current density (of 110 ma. per square centimetre initially) be safely used if the rectifiers are efflciently cooled.
  • the rectiflers are supported during the treatment upon a fiat shelf through which cooling water is circulated, means for ensuring good contact with the fiat surface of the shelf being provided.
  • a selenium rectifier behaves as if it consisted of a rectifying resistance and an ohmic resistance in parallel, the value of the latter varying from 20,000 ohms per square cm., for a good rectifier to 3,000 ohms per square cm. for a poor rectifier. It is only the current through the rectifying resistance that is effective in building up the rectifying properties. As this reverse rectifying resistance is built up the portion of the current flowing therethrough decreases as the applied voltage increases and the portion of current flowing through the ohmic resistance increases.
  • the portion of current, flowing through the rectifying resistance may become too small to be effective and the phenomenon previously referred to may occur, viz: that the current through the rectifier disc may remain at a given value for an inordinately long time, or even refuse to fall at all.
  • sumcient current passes through the rectifying resistance portion despite the shunting effect of the ohmic resistance to build up the resistance thereof during the whole time of electrical treatment.
  • the resistance which, according to the invention, is connected in series with each individual rectifier then serves to limit the current -through the shunt ohmic resistance, when the reverse resistance approaches its maximum, to control the heat losses in such oh'mic resistance.
  • Circular rectifier discs are normally madev with a base plate which is slightly concave at the back and we have found it necessary in the case of discs of 84 and 112 mm. in diameter to use a pressure of between 20 and 40 pounds to ensure that the base plate is in contact with the cooling surface throughout the whole area of the former and thus to ensure adequate cooling of the rectifier. For smaller size discs a smaller pressure is sufficient. resistance of 170 ohms per square cm. area in series with each rectifier.
  • the water is preferably circulated rapidly and a refrigerating plant used to cool the circulated water.
  • Fig. 1 is a perspective view of a portion of an apparatus for electrical treatment of circular selenium rectifiers of 84 mm. or 112 mm. diameter discs.
  • Fig. 2 is a front view, with a part in section of an apparatus for electrical treatment of lesser diameter selenium rectifiers.
  • Fig. 3 is a view partly in side elevation and partly in cross-section of another form of apparatus.
  • Fig. 4 is a view in cross section of still another form of apparatus.
  • a fiat h'ollow shelf I0 is provided, through which cooling water is circulated from aninlet pipe II to an outlet pipe (not shown).
  • a strip l2 having a curved front portion to allow rectifier discs I4 to be inserted partly thereunder, screws l3 protruding on the under side to locate the discs [4 in position.
  • the hollow shelf I0 is supported from a framework (not shown) which supports a member ll! of channel section at a little distance above the shelf l0.
  • Flexible metal bellows ll one for each rectifier disc are supported on individual supporting and insulating plates l6 secured to the member II, the latter being out away'to allow of flexible tubing I8, connected to the bellows, passing through the member 15 tothe rear thereof.
  • Each flexible tube I8 is connected in rear of the member I! to a pipe l9 connected to a suitable compressed air supply (not shown) a suitable cock or tap being provided to shut off the supply.
  • the shelf l0 forms one common terminal of the electric supply and makes contact with the base plate of each rectifier Whilst an apron member 20 attached to each bellows makes contact with the counter electrode of its individual rectifier when compressed air is admitted to the bellows.
  • Each apron member 20 is provided with a terminal tag 2
  • the operating member 30 of switch 23 is adapted when moved to one side to connect conductor 22 to a conductor 28 and when moved to the other side to connect conductor 22 to conductor 29, the middle portion being an offposition.
  • Conductors 28, 29 are connected to clips 23 and 21 which are supported in an insulated manner on the framework and carry resistances 24 and 25 of different values, provided with a common terminal 3 I.
  • the other side of the direct current supply used for the electrical treatment is connected to all the terminals 3i.
  • the resistances 24 and 25 are of values adapted for rectifier discs of 84 and 112 mm.
  • member I 5 is suitably marked with 84 on one side of each switch member 30 and with 112 on the other side so that the operator can initially by manipulation of the switch members 30 connect in the correct value of resistance for each rectifier.
  • the member I2 is mounted on side members 32, one only of which is shown, which members 32 are in turn held on shelf 10 by screws and butterfly nuts 33. Each screw passes through an elongated aperture 34 inmember 32 so that member I2 may be drawn forward such a distance that the screws l3 therein will properly locate the smaller of the two sizes of 'disc for which the apparatus is adapted.
  • the rectifier discs'to be electrically treated in this apparatus are constructed in accordance with U. S. Patent No. 2,314,104 granted March 16, 1943 to E. A. Richards and L. J. Ellison, entitled Metal rectifiers an area around the central aperture of each being covered with insulating varnish before the counter electrode is sprayed thereon. The pressure is exerted upon thispart at whicl. the counter electrode is not in contact with the selenium.
  • These remarks also apply to the apparatus shown in Figs. 2 and 3.
  • the resistances mounted in series with the rectifier discs are separated physically from these discs, so that heat developed in the resistances does not add to the diillculties of cooling.
  • Figs. 2 and 3 which show apparatus used for the electrical treatment of rectifier discs of 67 mm. and 45 mm. in diameter, cooling water is circulated through a hollow flat shelf ill by means not shown.
  • the shelf is provided on its upper surface with means for locating rectifier discs of either of two difi'erent sizes similar to the means shown in Fig. l.
  • a conical helical spring is provided for each rectifier, the base of each spring being anchored to a common frame member, 38 bolted to upright members '38 of the framework.
  • the lower end of each spring is fixed to a rod 38 which carries a contact member 31.
  • All the members .31 are held in the positions shown by a common member 40 which rests upon two cams 4i fixed on respective shafts 42 journalled in front and rear members of the framework.
  • Fixed also to shafts 42 are cranks 43 finished with handles 44 by means of which shafts 42 may be rotated to raise and lower member 40.
  • Each contact member 31 is connected by a strip45 to a conducting post 46 which in turn is connected by a flexible conductor to one terminal of a switch member (not shown).
  • This switch member is similar to the member shown in Fig. 1 and is for the purpose of connecting a resistance of one or other value in memori with each rectifier.
  • Fig. 4 shows in cross-section an apparatus for electrical treatment of rectifier discs of 25 mm. or 18 mm. diameter.
  • a lighter-pressure is sufficient and accordingly each disc 41 is pressed against the surface of the flat each end threeof.
  • the other ends of leaf springs- 54 are secured to respective plates fixed to the framework.
  • Extending forwardly of bar 53 at each end and secured to the bar is an arm '56 a depression of which is engaged by a lug 51 on a lever 58 pivoted at 59 to the framework.
  • a rod 80 furnished with a handle Bi is attached to each lever 58. In the position shown in the drawing the fiat bar 53 is held down with each spring 48 passing on a rectifier disc 41 by the weight of levers 58 and rods 60.
  • An insulating strip 62 is held on the upper surface of shelf l0 and formed with semi-circular portions to locate the rectifier discs in position.
  • levers 58 are pulled downwards to press springs 48 on to the rectifier discs, the springs 48 press downwith a rolling motion, which prevents a'ny scratching of the sprayed metal counter electrodes thereon.
  • the terminal 50 for each spring 48 is connected to the mid-point of two resistance spools 24 and 25.
  • the other end of resistance 24 is connected to a bus bar 83 and the other end of resistance 25 to a bus bar 84.
  • a common switch is provided for each shelf to connect the positive pole of the direct current supply either to bus-bar 83 or to bus bar 84 according to the size of the rectifier discs undergoing electrical treatment.
  • the negative pole of the supply is connected to discarded framework and thus to the fiat hollow plate What is claimed is:
  • Apparatus for the electrical treatment of selenium rectifiers comprising a channel for circulation of water, a flat surface for said channel on which the rectifiers are adapted to rest, means for circulating cooling water through said channel, means for holding said rectifiers in good heat conducting relation with the surface of said channel and contact means for connecting each of said rectifiers in series with an individual resistance in parallel to a common source of direct current.
  • Apparatus for electrical treatment of selenium rectifiers comprising a channel with means for circulating a cooling medium therethrough, a flat surface of said channel for supporting rectifiers, means for holding the rectifiers in good heat conducting relation with said surface, circuit means for connecting each of said rectifiers in series with an individual resistance in parallel to a common direct current source, said holding means comprising pressure applying means individual to each rectifier for pressing said rectifier against the surface of said channel and means for positioning the individual 'rectifiers beneath the pressure applying means.
  • Apparatus as claimed in claim 2 comprising means for positioning rectifiers of either of two different sizes beneath said pressure applying means, and switch means for connecting a resistance of either of two different values in series with the several rectifiers.
  • said pressure applying means comprises a flexible metal bellows for each rectifier and means for admitting fluid under pressure to each bellows.
  • said pressure applying means comprises a flexible metal bellows for each rectifier with means for admitting fluid under pressure to all said bellows simultaneously.
  • said pressure applying means comprises a conical helical spring for each rectifier and means is provided for allowing all the springs to exert pressure on the respective rectifiers and means is 8 gagltgdferirgogggngrgggig rectiners simultane REFERENCES CITED 7

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  • Rectifiers (AREA)
US500438A 1943-02-15 1943-08-28 Manufacture of dry contact rectifiers Expired - Lifetime US2449986A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2504/43A GB573936A (en) 1943-02-15 1943-02-15 Improvements in or relating to the manufacture of dry contact electric rectifiers

Publications (1)

Publication Number Publication Date
US2449986A true US2449986A (en) 1948-09-28

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US500438A Expired - Lifetime US2449986A (en) 1943-02-15 1943-08-28 Manufacture of dry contact rectifiers

Country Status (5)

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US (1) US2449986A (enrdf_load_stackoverflow)
BE (1) BE469234A (enrdf_load_stackoverflow)
ES (1) ES175950A1 (enrdf_load_stackoverflow)
FR (1) FR930971A (enrdf_load_stackoverflow)
GB (1) GB573936A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2626448A (en) * 1947-08-26 1953-01-27 Bell Telephone Labor Inc Apparatus for and method of treating selenium rectifiers
DE1010188B (de) * 1953-05-20 1957-06-13 Standard Elektrik Ag Verfahren zur Durchfuehrung der elektrischen Formierung von Selengleichrichtern
DE971373C (de) * 1951-11-07 1959-01-15 Siemens Ag Hilfseinrichtung zum elektrischen Formieren von Selengleichrichterplatten
DE1079743B (de) * 1953-02-10 1960-04-14 Siemens Ag Verfahren zur Herstellung von Selen-Gleichrichtern
US2942568A (en) * 1954-10-15 1960-06-28 Sylvania Electric Prod Manufacture of junction transistors

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2755536A (en) * 1951-11-07 1956-07-24 Ibm Method of producing transistors having substantially uniform characteristics

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2055216A (en) * 1929-08-30 1936-09-22 Mack Robert T Electrical condenser and its manufacture
US2229807A (en) * 1938-05-07 1941-01-28 Hermes Patentverwertungs Gmbh Method of manufacturing selenium rectifiers
US2237802A (en) * 1938-06-14 1941-04-08 Gen Electric Method of treating dry plate elements
US2261725A (en) * 1938-05-18 1941-11-04 Westinghouse Electric & Mfg Co Selenium rectifier
US2279187A (en) * 1939-01-11 1942-04-07 Union Switch & Signal Co Alternating electric current rectifier of the selenium type

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2055216A (en) * 1929-08-30 1936-09-22 Mack Robert T Electrical condenser and its manufacture
US2229807A (en) * 1938-05-07 1941-01-28 Hermes Patentverwertungs Gmbh Method of manufacturing selenium rectifiers
US2261725A (en) * 1938-05-18 1941-11-04 Westinghouse Electric & Mfg Co Selenium rectifier
US2237802A (en) * 1938-06-14 1941-04-08 Gen Electric Method of treating dry plate elements
US2279187A (en) * 1939-01-11 1942-04-07 Union Switch & Signal Co Alternating electric current rectifier of the selenium type

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2626448A (en) * 1947-08-26 1953-01-27 Bell Telephone Labor Inc Apparatus for and method of treating selenium rectifiers
DE971373C (de) * 1951-11-07 1959-01-15 Siemens Ag Hilfseinrichtung zum elektrischen Formieren von Selengleichrichterplatten
DE1079743B (de) * 1953-02-10 1960-04-14 Siemens Ag Verfahren zur Herstellung von Selen-Gleichrichtern
DE1010188B (de) * 1953-05-20 1957-06-13 Standard Elektrik Ag Verfahren zur Durchfuehrung der elektrischen Formierung von Selengleichrichtern
US2942568A (en) * 1954-10-15 1960-06-28 Sylvania Electric Prod Manufacture of junction transistors

Also Published As

Publication number Publication date
BE469234A (enrdf_load_stackoverflow) 1900-01-01
ES175950A1 (es) 1947-01-01
FR930971A (fr) 1948-02-10
GB573936A (en) 1945-12-13

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