US3008027A - Protection means against corona of live parts in electric vacuum melting furnaces - Google Patents
Protection means against corona of live parts in electric vacuum melting furnaces Download PDFInfo
- Publication number
- US3008027A US3008027A US855162A US85516259A US3008027A US 3008027 A US3008027 A US 3008027A US 855162 A US855162 A US 855162A US 85516259 A US85516259 A US 85516259A US 3008027 A US3008027 A US 3008027A
- Authority
- US
- United States
- Prior art keywords
- electric vacuum
- live parts
- protection means
- means against
- melting furnaces
- 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
Links
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/36—Coil arrangements
- H05B6/367—Coil arrangements for melting furnaces
Definitions
- the purpose of the present invention is to improve the aforesaid corona protection and to bring about reliable and permanent earthing of every part of the corona protection layer.
- the feature of the invention resides in that an earthed conductor of copper or other conductive material is placed in galvanic contact on the periphery of each conductive layer of the coil turns and along the other live parts in the vacuum space.
- the earthed conductor is placed suitably on the outer side and in the middle of the coil turns, which point is field-free, or where the magnetic field is weakest so that no heating of the conductor worth considering can arise. On the connection leads, the earthed conductor is so dimensioned that it is not unduly heated.
- the earthed conductors are fixed to their conductive shielding layers in any known manner.
- FIGURE 1 is an axial section through one turn of the coil along the line A-A in FIGURE 2, and an elevation view of one connection lead
- FIGURE 2 is a plan view of a part of the turn of the coil.
- the conductor which is assumed to be hollow for cooling purpose, is provided with an insulation 2 which is coated with a shielding layer 3 of electrically conducting material. This layer is divided into a number of parts separated from each other.
- an earthed conductor 4 is fixed. At this point the magnetic field is at its weakest and therefore the earthed conductors cannot be unduly heated.
- the eflicacy of the corona protecting layers may be maintained even if the conductivity of the layers should be decreased or nullified by internal crevices.
- conductors 4 are designated in the description as earthed conductors, this term shall also apply should they be connected to potentials lying below the critical corona limit.
- an electric vacuum induction melting furnace comprising a coil and connection leads to the coil, insulation covering the coil and connection leads, shielding layers on said insulation separated from one another along the turns of the coil and the connection leads, a conductor in galvanic contact with each shielding layer extending along its length at the point where the magnetic field is weakest, and a conducting lead connected to said conductor and to earth.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Induction Heating (AREA)
- Coils Of Transformers For General Uses (AREA)
Description
Nov. 7, 1961 I. BECKIUS ETAL 3,008,027
PROTECTION MEANS AGAINST CORONA OF LIVE PARTS IN ELECTRIC VACUUM MELTING FURNACES Filed Nov. 24, 1959 INVENTORS Var Beckg'as and A United States Patent Ofifice 3,008,027 Patented Nov. 7, 1961 3,008,027 PROTECTION MEANS AGAINST CORONA OF LIVE PARTS IN ELECTRIC VACUUM MELT- lNG FURNACES Ivar Beckius and Arne Olin, Vasteras, Sweden, assignors to Allmanna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a corporation of Sweden Filed Nov. 24, 1959, Ser. No. 855,162 2 Claims. (Cl. 21910.79)
In order to protect from corona live parts of electric vacuum melting furnaces, both the furnace coil itself and its connection leads in the vacuum container, it is usual to insulate these parts and to provide the insulation with electrically conducting earthed layers which are separated from each other. However, it is likely that crevices occur in one or more of said conducting layers so that each individual layer no longer has internal connection and therefore not even contact with the earthed lead, with the consequence that corona may occur at these crevices.
The purpose of the present invention is to improve the aforesaid corona protection and to bring about reliable and permanent earthing of every part of the corona protection layer. The feature of the invention resides in that an earthed conductor of copper or other conductive material is placed in galvanic contact on the periphery of each conductive layer of the coil turns and along the other live parts in the vacuum space.
The earthed conductor is placed suitably on the outer side and in the middle of the coil turns, which point is field-free, or where the magnetic field is weakest so that no heating of the conductor worth considering can arise. On the connection leads, the earthed conductor is so dimensioned that it is not unduly heated. The earthed conductors are fixed to their conductive shielding layers in any known manner.
The invention is illustrated by way of example on the accompanying drawing, wherein FIGURE 1 is an axial section through one turn of the coil along the line A-A in FIGURE 2, and an elevation view of one connection lead, and FIGURE 2 is a plan view of a part of the turn of the coil. The conductor, which is assumed to be hollow for cooling purpose, is provided with an insulation 2 which is coated with a shielding layer 3 of electrically conducting material. This layer is divided into a number of parts separated from each other. On the outer side of the coil and in the middle of said side an earthed conductor 4 is fixed. At this point the magnetic field is at its weakest and therefore the earthed conductors cannot be unduly heated.
By the new means the eflicacy of the corona protecting layers may be maintained even if the conductivity of the layers should be decreased or nullified by internal crevices.
Although the conductors 4 are designated in the description as earthed conductors, this term shall also apply should they be connected to potentials lying below the critical corona limit.
I claim:
1. In an electric vacuum induction melting furnace comprising a coil and connection leads to the coil, insulation covering the coil and connection leads, shielding layers on said insulation separated from one another along the turns of the coil and the connection leads, a conductor in galvanic contact with each shielding layer extending along its length at the point where the magnetic field is weakest, and a conducting lead connected to said conductor and to earth.
2. Apparatus as claimed in claim 1, said conductors being located on the outer sides of the shielding layers at the middle thereof.
References Cited in the file of this patent UNITED STATES PATENTS 2,352,166 Camilli June 27, 1944 FOREIGN PATENTS 419,284 Great Britain Feb. 9, 1934 627,507 Great Britain Aug. 10, 1949
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US855162A US3008027A (en) | 1959-11-24 | 1959-11-24 | Protection means against corona of live parts in electric vacuum melting furnaces |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US855162A US3008027A (en) | 1959-11-24 | 1959-11-24 | Protection means against corona of live parts in electric vacuum melting furnaces |
Publications (1)
Publication Number | Publication Date |
---|---|
US3008027A true US3008027A (en) | 1961-11-07 |
Family
ID=25320494
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US855162A Expired - Lifetime US3008027A (en) | 1959-11-24 | 1959-11-24 | Protection means against corona of live parts in electric vacuum melting furnaces |
Country Status (1)
Country | Link |
---|---|
US (1) | US3008027A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3146300A (en) * | 1959-09-18 | 1964-08-25 | Asea Ab | Corona protection screen for inductor coils in vacuum furnaces |
US4016389A (en) * | 1975-02-21 | 1977-04-05 | White Gerald W | High rate ion plating source |
US4184135A (en) * | 1978-04-10 | 1980-01-15 | Monsanto Company | Breakapart single turn RF induction apparatus |
US5216690A (en) * | 1992-03-11 | 1993-06-01 | Hanks Charles W | Electron beam gun with grounded shield to prevent arc down |
US20110073591A1 (en) * | 2008-07-17 | 2011-03-31 | Seiichi Sawatsubashi | Guide Chip Structure for High-Frequency Induction Heating Coil |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB419284A (en) * | 1933-03-07 | 1934-11-07 | Emi Ltd | Improvements in and relating to inductance coils and the like for use in radio-frequency current circuits |
US2352166A (en) * | 1942-02-10 | 1944-06-27 | Gen Electric | Electric induction apparatus |
GB627507A (en) * | 1945-09-29 | 1949-08-10 | Mario Tama | Improvements in or relating to heating inductor coils for use in induction furnaces |
-
1959
- 1959-11-24 US US855162A patent/US3008027A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB419284A (en) * | 1933-03-07 | 1934-11-07 | Emi Ltd | Improvements in and relating to inductance coils and the like for use in radio-frequency current circuits |
US2352166A (en) * | 1942-02-10 | 1944-06-27 | Gen Electric | Electric induction apparatus |
GB627507A (en) * | 1945-09-29 | 1949-08-10 | Mario Tama | Improvements in or relating to heating inductor coils for use in induction furnaces |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3146300A (en) * | 1959-09-18 | 1964-08-25 | Asea Ab | Corona protection screen for inductor coils in vacuum furnaces |
US4016389A (en) * | 1975-02-21 | 1977-04-05 | White Gerald W | High rate ion plating source |
US4184135A (en) * | 1978-04-10 | 1980-01-15 | Monsanto Company | Breakapart single turn RF induction apparatus |
US5216690A (en) * | 1992-03-11 | 1993-06-01 | Hanks Charles W | Electron beam gun with grounded shield to prevent arc down |
WO1993018538A1 (en) * | 1992-03-11 | 1993-09-16 | Hanks Charles W | Electron beam gun with grounded shield to prevent arc down |
USRE35024E (en) * | 1992-03-11 | 1995-08-22 | Hanks; Charles W. | Electron beam gun with grounded shield to prevent arc down |
DE4391006C2 (en) * | 1992-03-11 | 2002-10-17 | Charles W Hanks | electron beam gun |
US20110073591A1 (en) * | 2008-07-17 | 2011-03-31 | Seiichi Sawatsubashi | Guide Chip Structure for High-Frequency Induction Heating Coil |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
GB913386A (en) | Corona protection screen for inductor coils of vacuum furnaces | |
US2125869A (en) | Electrical conductor | |
US2992405A (en) | Insulating and cooling devices | |
DK144870B (en) | VACUUM CHANGES | |
GB1120108A (en) | Termination of insulators | |
US3008027A (en) | Protection means against corona of live parts in electric vacuum melting furnaces | |
GB1217761A (en) | The transfer of current between a common normally-conductive conductor and a number of electrically parallel superconductor current-carriers | |
GB1113964A (en) | Electromagnetic forming | |
GB1117297A (en) | Voltage lead entrance for encapsulated electrical devices | |
ES346865A1 (en) | Electric cable for polyphase current | |
KR100742499B1 (en) | Core of magentic shield type superconducting cable and superconducting cable having the same | |
GB1489675A (en) | Generator having shielded current transformers positioned therein | |
US2620366A (en) | Induction stirrer | |
GB1223636A (en) | Improved magnet coil | |
ES397571A1 (en) | Shielding tape earthing device for high voltage cables | |
GB1479545A (en) | Stator coil assemblies for rotary electric machines | |
US2381278A (en) | Inductive heating coil shielding | |
GB769762A (en) | Means for cooling electrical windings | |
US3330936A (en) | Electrically heated blanket, guarded against touching the live heater element | |
US2310501A (en) | Device for reducing eddy current losses in stator end plates | |
GB861276A (en) | An improved electric vacuum melting furnace | |
GB846379A (en) | Improvements in electrical vacuum furnaces | |
US1701334A (en) | Transformer | |
GB1459579A (en) | Heat-generating pipe utilizing skin effect current having an insulated wire provided with a divided corona shield layer | |
GB1123200A (en) | Detection of faults in electrical induction furnaces |