EP0203041B1 - An electric power resistor structure - Google Patents
An electric power resistor structure Download PDFInfo
- Publication number
- EP0203041B1 EP0203041B1 EP19860830124 EP86830124A EP0203041B1 EP 0203041 B1 EP0203041 B1 EP 0203041B1 EP 19860830124 EP19860830124 EP 19860830124 EP 86830124 A EP86830124 A EP 86830124A EP 0203041 B1 EP0203041 B1 EP 0203041B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- plate
- electric power
- power resistor
- resistor structure
- reeds
- 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
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C1/00—Details
- H01C1/01—Mounting; Supporting
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C3/00—Non-adjustable metal resistors made of wire or ribbon, e.g. coiled, woven or formed as grids
- H01C3/10—Non-adjustable metal resistors made of wire or ribbon, e.g. coiled, woven or formed as grids the resistive element having zig-zag or sinusoidal configuration
- H01C3/12—Non-adjustable metal resistors made of wire or ribbon, e.g. coiled, woven or formed as grids the resistive element having zig-zag or sinusoidal configuration lying in one plane
Definitions
- This invention relates to an electric power resistor structure particularly intended for use with generic resistive applications.
- resistors i.e. electric circuit components representing a dissipative obstacle or resistance to the flowing current to originate a voltage drop and degrade the electric power they absorb into heat
- resistors i.e. electric circuit components representing a dissipative obstacle or resistance to the flowing current to originate a voltage drop and degrade the electric power they absorb into heat
- the resistive electric element referred to as the grid herein below, is characterised by a metal sheet comprising a plurality of coils which increase the length of the resistive path for a given size and, accordingly, determine the value of its electric resistance.
- a further problem encountered is that in some operating conditions the resistors are liable to attain very high temperatures because the equality of the amount of heat generated per second to the amount of heat concurrently delivered by the resistor surface to the environment ceases to exist, and the temperature rise results in the material comprising the resistor expanding, with the consequence that the coils in their expanding movement, may contact one another and short out. This would put the entire circuit including the resistor out of operation.
- DE-C-939 461 discloses an electric power resistor structure as defined in the precharacterizing part of claim 1.
- the power resistor structure does not have a reed passed between one pair of windings and the next so as to prevent them, during deformation of the material when subjected to a high temperature, from contacting one another and cause a short circuit situation.
- the aim of this invention is to obviate such prior drawbacks by providing a structure of an electric power resistor (grid), which can operate in a troublefree manner even at high temperatures and high ohmic values, without undergoing shorts that would lead to discontinuing the operation of the electric circuit comprising it.
- grid electric power resistor
- a further object of the invention is to provide a grid which affords optimum operational features even where subjected to any vibrations from external factors.
- a not least object of the invention is to provide a grid which has the peculiarity that it can be quickly removed from its housing for replacement or for any required maintenance or servicing operations.
- the grid of this invention comprises a plate generally indicated at 2 and provided with several coils each indicated at 3 and formed by providing partial cross spacings 4 across the plate 2 at equal distances from one another.
- the plate 2 is advantageously provided, on each of its opposing longitudinal sides, with a stiffening element 5 extending along said two sides and being isolated electrically from each of the coils 3 and the plate 2.
- the stiffening element 5 is "U-shaped" and connected rigidly at its ends to the juxtaposed peripheral portions of the plate 2 by a double punching formation advantageously performed on either faces of the plate 2 to provide for a more secure attachment between the plate 2 and the two stiffening elements 5 while accommodating any unrestricted and uniform expansion of the coils 3 when the resistor is subjected to a high temperature.
- the stiffening element 5 is provided with a strengthening fin 6 extending parallel along the axis of the stiffening element 5.
- the first reed 7 is advantageously passed, as shown in Figures 2 and 3, between one pair of coils 3 and the next, so as to prevent them, during deformation of the material when subjected to a high temperature, from contacting one another and cause a short circuit situation which would put the resistor out of operation.
- the two second reeds 8 and 9 are interposed respectively to the stiffening element and those portions of the first reed 7 which face alternately the two faces of the plate 2.
- stiffening elment 5 has a width substantially equal to or larger than the width of the first reed 7 and of the two second reeds 8 and 9, and a shorter length than the two second reeds 8 and 9.
- the plate 2 is also provided on each of its short sides with a seat 10 adapted for releasable retention in its housing and to enable its positioning either individually or with other plates.
- the resistor structure of this invention is particularly advantageous in that it allows uniform sliding of the coils as the material comprising the resistor expands when subjected to high temperatures, while preventing, however, the occurrence of deformations resulting in the coils contacting one another and shorting out to cut the resistor out of operation.
- the materials used and the dimensions may be any ones contingent on requirements and the state of the art.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Details Of Resistors (AREA)
Description
- This invention relates to an electric power resistor structure particularly intended for use with generic resistive applications.
- AS is known, resistors, i.e. electric circuit components representing a dissipative obstacle or resistance to the flowing current to originate a voltage drop and degrade the electric power they absorb into heat, are utilised in many fields for such different applications as starting and braking electric motors, grounding the star centre of transformers, and dissipative type generic electric loads.
- With a wide range of power resistors the resistive electric element, referred to as the grid herein below, is characterised by a metal sheet comprising a plurality of coils which increase the length of the resistive path for a given size and, accordingly, determine the value of its electric resistance.
- In order to attain the ohmic value range required by the design of the involved systems by the electric resistors it is necessary to increase the number of the coils considerably, the cross- sectional areas whereof decreases proportionately, for a given thickness this makes the metal sheet progressively weaker mechanically and virtually unusable unless suitably strengthened.
- A further problem encountered is that in some operating conditions the resistors are liable to attain very high temperatures because the equality of the amount of heat generated per second to the amount of heat concurrently delivered by the resistor surface to the environment ceases to exist, and the temperature rise results in the material comprising the resistor expanding, with the consequence that the coils in their expanding movement, may contact one another and short out. This would put the entire circuit including the resistor out of operation.
- In attempt to solve the problem of the grid stiffening and deformation-proofing, several solutions have been tried such as stiffening the coils by ribbing, or encapsulating same in strengthening elements which strengthen the grid mechanically and attenuate the deformative phenomenon reaching high temperature levels.
- These and other prior expedients, while improving the resistor operation, have failed to thoroughly solve the problem deriving from the deformation ensuing from expansion of the coils thereof, especially with high ohmic value grids.
- DE-C-939 461 discloses an electric power resistor structure as defined in the precharacterizing part of claim 1. The power resistor structure does not have a reed passed between one pair of windings and the next so as to prevent them, during deformation of the material when subjected to a high temperature, from contacting one another and cause a short circuit situation.
- The aim of this invention is to obviate such prior drawbacks by providing a structure of an electric power resistor (grid), which can operate in a troublefree manner even at high temperatures and high ohmic values, without undergoing shorts that would lead to discontinuing the operation of the electric circuit comprising it.
- Within the above aim, it is an important object of this invention to provide a grid adapted to faultlessly withstand electric power overloads in the course of its operation.
- A further object of the invention is to provide a grid which affords optimum operational features even where subjected to any vibrations from external factors.
- It is another object of this invention to provide a grid which can be readily formed from commercially available materials and of low cost, to thereby favour its extensive application to a variety of fields.
- A not least object of the invention is to provide a grid which has the peculiarity that it can be quickly removed from its housing for replacement or for any required maintenance or servicing operations.
- The above aim, and these and other objects, are achieved by an electric power resistor structure as defined in claim 1.
- Further features and advantages will be more clearly apparent from the following detailed description of a grid according to the invention, shown by way of illustration in the accompanying drawings, where:
- Figure 1 is a cutaway plan view of the inventive grid;
- Figure 2 is a fragmentary, exploded perspective view of the grid according to this invention; and
- Figure 3 is a sectional view taken along the line III-III in Figure 1, showing the inventive grid.
- With particular reference to the drawing figures, the grid of this invention, comprehensively designated 1, comprises a plate generally indicated at 2 and provided with several coils each indicated at 3 and formed by providing
partial cross spacings 4 across theplate 2 at equal distances from one another. - The
plate 2 is advantageously provided, on each of its opposing longitudinal sides, with astiffening element 5 extending along said two sides and being isolated electrically from each of thecoils 3 and theplate 2. - More precisely, the
stiffening element 5 is "U-shaped" and connected rigidly at its ends to the juxtaposed peripheral portions of theplate 2 by a double punching formation advantageously performed on either faces of theplate 2 to provide for a more secure attachment between theplate 2 and the twostiffening elements 5 while accommodating any unrestricted and uniform expansion of thecoils 3 when the resistor is subjected to a high temperature. - In order to prevent mechanical deflection of the
plate 2 and/or constrain the material expansion on reaching a high temperature, which situations could result in a short-out, thestiffening element 5 is provided with a strengtheningfin 6 extending parallel along the axis of thestiffening element 5. - Between each
stiffening element 5 and eachcoil 3 and over the entire length of theplate 2, there extend respectively afirst reed 7 and twosecond reeds 8 and 9, one for each face of thecoils 3 and theplate 2, to electrically isolate thestiffening element 5 from the plate and the coils. - More specifically, the
first reed 7 is advantageously passed, as shown in Figures 2 and 3, between one pair ofcoils 3 and the next, so as to prevent them, during deformation of the material when subjected to a high temperature, from contacting one another and cause a short circuit situation which would put the resistor out of operation. - The two
second reeds 8 and 9 are interposed respectively to the stiffening element and those portions of thefirst reed 7 which face alternately the two faces of theplate 2. - It is clear that instead of the two
reeds 8 and 9, it is possible to use just one reed also it "U-shaped" so as to cover entirely the inner surface of theelement 5 advantageously preventing an eventual short circuit situation in case theelement 5 it is inserted by force on theplate 2. - It is further pointed out that the
stiffening elment 5 has a width substantially equal to or larger than the width of thefirst reed 7 and of the twosecond reeds 8 and 9, and a shorter length than the twosecond reeds 8 and 9. - The
plate 2 is also provided on each of its short sides with aseat 10 adapted for releasable retention in its housing and to enable its positioning either individually or with other plates. - It has been found in practice that the resistor structure of this invention is particularly advantageous in that it allows uniform sliding of the coils as the material comprising the resistor expands when subjected to high temperatures, while preventing, however, the occurrence of deformations resulting in the coils contacting one another and shorting out to cut the resistor out of operation.
- In practicing the invention, the materials used and the dimensions may be any ones contingent on requirements and the state of the art.
Claims (4)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT2180085U IT8521800V0 (en) | 1985-05-14 | 1985-05-14 | STRUCTURE OF ELECTRIC POWER RESISTOR. |
IT2180085U | 1985-05-14 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0203041A2 EP0203041A2 (en) | 1986-11-26 |
EP0203041A3 EP0203041A3 (en) | 1987-04-15 |
EP0203041B1 true EP0203041B1 (en) | 1989-09-13 |
Family
ID=11187015
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19860830124 Expired EP0203041B1 (en) | 1985-05-14 | 1986-05-13 | An electric power resistor structure |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0203041B1 (en) |
DE (1) | DE3665643D1 (en) |
IT (1) | IT8521800V0 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11901850B2 (en) | 2019-12-18 | 2024-02-13 | Milwaukee Electric Tool Corporation | Power tool having stamped brake resistor |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2823593B1 (en) * | 2001-04-12 | 2003-07-18 | Metal Deploye Sa | ELECTRIC RESISTANCE IN RAISED SHEET |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR617515A (en) * | 1926-06-14 | 1927-02-21 | Electric plate resistors, for rheostats, electric heaters and other applications | |
FR903775A (en) * | 1943-12-02 | 1945-10-15 | Cie Generale De Travaux D Ecla | Improvements to electrical resistance elements |
DE939461C (en) * | 1952-08-29 | 1956-02-23 | Siemens Ag | Insulation support for resistance elements |
FR2517163A1 (en) * | 1981-11-23 | 1983-05-27 | Metal Deploye | ELECTRIC RESISTANCE IN TOLE RAIDIE |
-
1985
- 1985-05-14 IT IT2180085U patent/IT8521800V0/en unknown
-
1986
- 1986-05-13 DE DE8686830124T patent/DE3665643D1/en not_active Expired
- 1986-05-13 EP EP19860830124 patent/EP0203041B1/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11901850B2 (en) | 2019-12-18 | 2024-02-13 | Milwaukee Electric Tool Corporation | Power tool having stamped brake resistor |
Also Published As
Publication number | Publication date |
---|---|
EP0203041A2 (en) | 1986-11-26 |
IT8521800V0 (en) | 1985-05-14 |
DE3665643D1 (en) | 1989-10-19 |
EP0203041A3 (en) | 1987-04-15 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4462657A (en) | Compliant electrical connector for flat conductors | |
US7933111B2 (en) | Metallized plastic film and film capacitor | |
US3995103A (en) | Electrical bussing and jumper assembly | |
US3463967A (en) | Panelboard load center | |
US2907968A (en) | Edgewise wound reactor coils and method of making the same | |
EP0203041B1 (en) | An electric power resistor structure | |
US3571488A (en) | Enclosed bus duct | |
US3961129A (en) | Electrical bussing and jumper assembly | |
US2907965A (en) | Reactor with end shielding having disk laminations | |
EP0250982B1 (en) | Space block control means for dynamoelectric machine | |
US3427391A (en) | Composite superconductive conductor | |
US2736785A (en) | Electric resistor structure | |
EP0071360B1 (en) | Terminal assembly for circuit interrupter | |
US5917404A (en) | Power resistor | |
US3502824A (en) | Slide selector contact switch with orthogonal u-shaped spring detent | |
CA2337483A1 (en) | Resistive short-circuit current limiter having a conductor track structure made of high-tc superconductor material and method for producing the current limiter | |
US2868937A (en) | Grid-type resistance units | |
US2918639A (en) | Spacer for electrical windings | |
US10685792B2 (en) | System and method for thermal protection of automatic transfer switch | |
US4511874A (en) | Fatigue-resistant fuse strip | |
EP0071385B1 (en) | Terminal assembly for circuit interrupter | |
US3164797A (en) | Wire wound electrical resistor | |
US2725448A (en) | Resistance apparatus | |
US4630018A (en) | Molded case circuit breaker current transformer with spiral bus | |
JPH0621204Y2 (en) | Lightning arrester |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): DE FR GB |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): DE FR GB |
|
17P | Request for examination filed |
Effective date: 19870710 |
|
17Q | First examination report despatched |
Effective date: 19880930 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB |
|
REF | Corresponds to: |
Ref document number: 3665643 Country of ref document: DE Date of ref document: 19891019 |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20050412 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20050420 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20050530 Year of fee payment: 20 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: PE20 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION Effective date: 20060512 |