EP1372165A1 - Transformator mit Temperaturdetektor und elektrisches Gerät welches ihn verwendet - Google Patents

Transformator mit Temperaturdetektor und elektrisches Gerät welches ihn verwendet Download PDF

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Publication number
EP1372165A1
EP1372165A1 EP02254013A EP02254013A EP1372165A1 EP 1372165 A1 EP1372165 A1 EP 1372165A1 EP 02254013 A EP02254013 A EP 02254013A EP 02254013 A EP02254013 A EP 02254013A EP 1372165 A1 EP1372165 A1 EP 1372165A1
Authority
EP
European Patent Office
Prior art keywords
transformer
temperature
primary winding
responsive switch
core
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.)
Granted
Application number
EP02254013A
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English (en)
French (fr)
Other versions
EP1372165B1 (de
Inventor
Takeshi c/o Tabuchi Electric Co. Ltd. Morimoto
Takehiko c/o Tabuchi Electric Co. Ltd. Adachi
Keisuke c/o Tabuchi Electric Co. Ltd. Warashina
Shinobu c/o Tabuchi Electric Co. Ltd. Miyazaki
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.)
Tabuchi Electric Co Ltd
Original Assignee
Tabuchi Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Tabuchi Electric Co Ltd filed Critical Tabuchi Electric Co Ltd
Priority to EP20020254013 priority Critical patent/EP1372165B1/de
Priority to DE2002605468 priority patent/DE60205468T2/de
Publication of EP1372165A1 publication Critical patent/EP1372165A1/de
Application granted granted Critical
Publication of EP1372165B1 publication Critical patent/EP1372165B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/40—Structural association with built-in electric component, e.g. fuse
    • H01F27/402—Association of measuring or protective means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/085—Cooling by ambient air
    • 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
    • H05B6/64—Heating using microwaves
    • H05B6/66—Circuits
    • H05B6/662—Aspects related to the boost transformer of the microwave heating apparatus
    • 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
    • H05B6/64—Heating using microwaves
    • H05B6/66—Circuits
    • H05B6/666—Safety circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/40—Structural association with built-in electric component, e.g. fuse
    • H01F27/402—Association of measuring or protective means
    • H01F2027/406—Temperature sensor or protection

Definitions

  • the present invention relates to a transformer having a high temperature during the operation thereof and an electric appliance utilizing such transformer.
  • a transformer having a high temperature during the operation is generally air-cooled by a forced draft blower and designed to have the highest permissible operating temperature and the highest critical temperature that may be attained in the event of an abnormal condition such as occurring when the blower halts.
  • the transformer falling within the category of the European Standards E1-96 is prescribed to have the highest permissible operating temperature at 200 °C and the highest critical temperature at 250°C.
  • a transformer core has conventionally been employed of a relatively bulky size effective to render the transformer to attain a temperature of about 180°C at all times during its normal operation. For this reason, the conventional transformer is bulky and heavy, resulting in increase of the cost.
  • a thermal cut off fuse or a temperature responsive fuse is electrically connected in series with the transformer primary winding so that when the temperature of the transformer exceeds a predetermined value, the fuse can break to thereby interrupt supply of an electric power from an electric power source to the transformer primary winding.
  • the thermal cut off fuse is fitted to an outer side of either the transformer primary winding or the transformer secondary winding, it is incapable of accurately detecting the temperature of that portion of the transformer which tends to attain the highest temperature during the normal operation thereof.
  • the region of the transformer where the highest possible temperature may be attained during the normal operation of the transformer may be thought to reside in a center area of the cross-section of the transformer windings.
  • the region of the transformer where the next highest possible temperature may be attained during the normal operation resides in an area delimited between the transformer windings at which the cooling effect is low and the transformer core encircled by the transformer windings.
  • a temperature sensor cannot be inserted in the center area of the cross-section of the transformer windings, it appears appropriate to detect the temperature prevailing between the transformer windings and the transformer core.
  • the present invention is based on the above discussed findings by the inventor(s) of the present invention and is intended to provide a transformer wherein arrangement has been made to detect the temperature prevailing at an area between the transformer windings and the transformer core, wherefore not only can the transformer core have a reduced size and a reduced weight, but the transformer will not attain a temperature in excess of the highest critical temperature indicative of an occurrence of the abnormal condition.
  • the transformer includes a transformer core, primary and secondary windings wound around the transformer core, and a temperature responsive switch connected in series with the primary winding and adapted to be switched off in response to increase of a temperature to a value equal to or higher than a predetermined value.
  • the primary winding and the secondary windings are spaced from each other in a direction axially thereof, and the temperature responsive switch referred to above is positioned between one of the primary and secondary windings and the transformer core.
  • the temperature responsive switch can interrupt input to the primary winding when the temperature responsive switch then monitoring the temperature prevailing between the secondary winding, and the transformer core or between the primary winding and the transformer core which tends to be heated to the highest temperature detects increase of such temperature in excess of the predetermined value. Accordingly, the increase of the transformer temperature can be suppressed and, therefore, it is possible not only to reduce the size of the transformer core, but also to render the transformer itself to be compact in size and lightweight. Also, since the temperature responsive switch can be supported sandwiched between the secondary or primary winding and the transformer core, no extra fixture is needed.
  • each of the transformer core, the primary winding, the secondary winding and the temperature responsive switch is impregnated with an electrically insulating varnish having a thermal conductivity not lower than 0.25 W/m.°C. While as hereinbefore discussed the highest temperature region of the transformer may be thought residing at the center area of the cross-section of the windings, in the transformer of the structure described above in accordance with the present invention, the use of the electrically insulating varnish of a high thermal conductivity that is impregnated in the primary and secondary windings makes it possible to transmit heat, evolved in the center area of the cross-section of the windings, to a surface area of the transformer efficiently and with no localized variation.
  • the electrically insulating varnish filled in between the temperature responsive switch and the windings facilitate an efficient transmission of heat appearing on surfaces of the windings to the temperature responsive switch.
  • the temperature responsive switch is effective to detect the temperature as close to the highest possible temperature of the transformer as possible accurately and with minimized localized variation that depends on the position where the temperature responsive switch is disposed. Also, since thermal conduction can be facilitated between the transformer core and each of the primary and secondary windings, a localized increase of the temperature of the transformer core can be effectively suppressed, making it possible to further reduce the size of the transformer core.
  • the transformer core includes a generally E-shaped fist core piece and a generally I-shaped or E-shaped second core piece positioned one above the other, having an intermediate leg around which the primary and secondary windings are wound with the secondary winding positioned above the primary winding.
  • the temperature responsive switch is utilized to detect the temperature prevailing between an inside of the secondary winding, tending to attain the highest temperature, and the transformer core.
  • the primary winding has a terminal support fitted thereto.
  • the terminal support has a first terminal with which one end of the primary winding is connected, and a second terminal connected with one of lead lines extending from the temperature responsive switch.
  • the other of the lead lines of the temperature responsive switch is connected with the other end of the primary winding.
  • a junction between the other end of the primary winding and the other of the lead lines of the temperature responsive switch is supported by the terminal support. According to this embodiment, no extra connecting terminal for supporting such junction is needed.
  • the present invention also provides an electric appliance utilizing the transformer of the type discussed above.
  • this electric appliance includes, within a casing, the transformer having a capability of detecting the temperature, an electric element adapted to be driven by the transformer, and a cooling fan accommodated for cooling the transformer.
  • the temperature responsive switch incorporated in the transformer in the manner discussed hereinabove is disposed on one side of the transformer remote from the opposite side of the transformer where a current of cooling air induced by the cooling fan impinges.
  • a microwave oven 1 includes an oven casing 2 made up of a bottom wall 21, a top wall 22, a pair of side walls 23 and a rear wall 24, all assembled together to represent a generally rectangular box opening in a forward direction.
  • the casing 2 also has a hingedly supported door for selectively opening or closing a front opening of the casing 2 or an access opening leading into an oven chamber inside the casing 2.
  • a transformer 12 is disposed within the instrument compartment and fixedly mounted on the bottom wall 21 of the oven casing 2, with a magnetron 16 positioned above this transformer 12, and a cooling fan 3 is positioned rearwardly of the transformer 12 and the magnetron 16.
  • the cooling fan 3 is utilized to introduce air from the outside of the oven casing 2 through a draught window 27 defined in the rear wall 24, to thereby blow the transformer 12 and the magnetron 16 to cool the transformer 12 and the magnetron 16.
  • the current of cooling air used to cool the transformer 12 and the magnetron 16 is subsequently vented to the outside of the casing 2 through a vent hole not shown, but defined in one side of the top wall 22.
  • the transformer 12 includes a core 18 made up of a first core piece 18e and a second core piece 18i positioned one above the other.
  • the first core piece 18e is of a generally E-shaped configuration including a pair of outer legs 18eo connected together by means of a bridge portion and an intermediate leg 18ec extending parallel from the bridge and positioned between the outer legs 18eo.
  • the second core piece 18i is of a generally I-shaped configuration and coupled fixedly with the first core piece 18e with the outer legs 18eo of the first core piece 18i held in contact with the second core piece 18i.
  • a coil of secondary winding 14 is mounted around the intermediate leg 18ec, a coil of heater winding 17 is then mounted around the intermediate leg 18ec and, finally, a coil of primary winding 13 is mounted around the intermediate leg 18ec, prior to the second core piece 18i coupled to the first core piece 18e.
  • a portion of the coiled primary winding 13 which is held in contact with the first core piece 18i is covered by an electrically insulating sheet and, similarly, the coiled secondary winding 14 may, if required, have its outer surface completely covered by an electrically insulating sheet.
  • the coiled primary winding 13, the coiled secondary winding 14 and the coiled heater winding 17 are spaced in a direction axially thereof about the intermediate leg 18ec and positioned in this specific order from below as viewed in Fig. 2.
  • the coiled secondary winding 14 has starting and terminating lead ends 14e and 14f opposite to each other, the starting lead end 14e being connected with a terminal eyelet 14m while the terminating lead end 14f of the coiled secondary winding 14 is connected with a generally flag-shaped terminal element 14h.
  • the coiled heater winding 17 also has starting and terminating lead ends 17e and 17f that are connected with generally flag-shaped terminal elements 17h1 and 17h2, respectively.
  • starting and terminatating used in connection with opposite ends of any winding used in the present invention are intended to means one end of the wire first laid on a winding mandrel when winding starts and the opposite end of the same wire led outwardly from the coiled wire at the time of termination of the winding, respectively.
  • the coiled primary winding 13 carries a terminal support 40.
  • This terminal support 40 is made of a synthetic resin and secured to a lower end of the coiled primary winding 13 remote from the coiled heater winding 17 by means of an electrically insulating transparent tape 50.
  • a self-resettable temperature responsive switch (hereinafter referred to as a "thermostat") 30 has first and second lead lines 31 and 32 inserted into the inside of the coiled primary winding 13. This thermostat 30 is electrically connected directly with the coiled primary winding 13 and, as clearly shown in Fig.
  • one end of the first lead line 31 and a lead line 13e continued from the starting end of the coiled primary winding 13 are electrically connected with each other by means of a soldering technique to thereby define a junction 35.
  • the thermostat 30 itself may be covered by an electrically insulating sheet.
  • the junction 35 between the end of the first lead line 31 and the lead line 13e is positioned adjacent an undersurface of the terminal support 40 and is in turn fixed to the coiled primary winding 13 by means of an electrically insulating tape 50 together with the terminal support 40.
  • the terminal support 40 has first and second terminals 41 and 42, and a lead line 13f continued from the terminating lead end of the coiled primary winding 13 is connected with the first terminal 41 whereas the first lead line 31 of the thermostat 30 is connected with the second terminal 42.
  • the terminal eyelet 14m connected with the lead line 14e continued from the starting lead end of the coiled secondary winding 14 is connected with the first core piece 18e and, hence, the transformer core 18 by means of a set screw 18n threaded into a screw hole 18en defined in the second core piece 18e as best shown in Fig. 3.
  • the thermostat 30 is mounted on the intermediate leg 18ec of the first core piece 18e and within a center void of the coiled secondary winding 14 through a gap between an inner periphery of the coiled heater winding 17 and the intermediate leg 18ec, so that the thermostat 30 can have its temperature sensing surface positioned at an upper portion of an inner peripheral face of the coiled secondary winding 14 and generally intermediate portion in a widthwise direction, indicated by the double headed arrows LR, of the center void of the coiled secondary winding 14.
  • the second core piece 18i is, while being pressed against respective end faces of the outer legs 18eo of the first core piece 18e, secured rigidly thereto as at 18m (Fig. 3) by means of a fillet welding technique, to thereby complete the transformer 12.
  • the resultant transformer 12 is then mounted on a base plate 19 that is spot-welded to an undersurface of the second core piece 18i.
  • the transformer 12 having the base plate 19 fitted thereto is mounted on the bottom wall 21 of the oven casing 2 by means of a plurality of, for example, four, fastening elements such as bolts having been passed through associated mounting holes defined in four comer regions of the base plate 19.
  • the transformer core 18 is grounded to the oven casing 2.
  • the transformer 12 assembled in the manner described above is vacuum impregnated with an electrically insulating varnish having a high thermal conductivity.
  • the varnish coats surfaces of the core 18 and the thermostat 30 and penetrates into the first and second windings 13 and 14.
  • This electrically insulating varnish is of a kind made of a polyester resin mixed with a finely divided powder of silica and has a thermal conductivity of 0.25 W/m ⁇ °C or higher, in contrast to 0.19 W/m ⁇ °C exhibited by the standard electrically insulating varnish.
  • An example of the varnish of this kind having a high thermal conductivity includes Varnish No. 50S manufactured by and sold from The P.D. George Company.
  • Fig. 5 illustrates an electric circuit diagram showing a magnetron drive circuit used in the microwave oven utilizing the transformer 12 that is assembled as hereinbefore in accordance with the present invention.
  • the coiled primary winding 13 of the transformer 12 is electrically connected with a commercial power source 33 through the thermostat 30 while an output voltage from the coiled secondary winding 14 of the same transformer 12 is adapted to be rectified and smoothened by a half-wave voltage-doubling rectifying circuit 15 to provide a direct current high voltage which is in turn supplied to a magnetron 16.
  • a heater of the magnetron 16 preheated by the coiled heater winding 17 built in the transformer 12 the magnetron 16 generates microwaves when the direct current high voltage is supplied thereto from the half-wave voltage-doubling rectifying circuit 15.
  • the primary and secondary windings 13 and 14 are would on the transformed core 18 while spaced axially from each other, and the heater winding 17 is wound between the primary and secondary windings 13 and 14.
  • the lead line 13f continued from the terminating end of the primary winding 13 is connected with the first terminal 41 of the terminal support 40 and the first lead line 31 of the thermostat 30 is connected with the second terminal 42 of the terminal support 40.
  • the lead line 13e continued from the starting end of the primary winding 13 is connected with the second lead line 32 of the thermostat 30.
  • the thermostat 30 is electrically connected in series with the primary winding 13 through the lead lines 31 and 32 and is interposed between the secondary winding 14 and the transformer core 18.
  • the lead line 14e continued from the starting end of the secondary winding 14 is connected with the transformer core 18 through the terminal eyelet 14m and the lead line 14f continued from the terminating end of the secondary winding 14 is connected with an input end of the half-wave voltage-doubling rectifying circuit 15 through the flag-shaped terminal element 14h1.
  • the two opposite lead lines 17e and 17f of the heater winding 17 are connected with the heater of the magnetron 16 through the flag-shaped terminal elements 17h1 and 17h2 that are connected therewith.
  • the temperature responsive switch 30 monitoring the temperature of a region between the secondary winding 14 and the transformer core 18 which will attain the highest temperature detects such temperature exceeding a predetermined temperature, the temperature responsive switch 30 is turned off to interrupt supply of the electric power from the power source 33 to the primary winding 13. Accordingly, any undesirable increase of the temperature of the transformer can advantageously be suppressed and, for this reason, the transformer core can have a reduced size. Also, since the temperature of the transformer 12 during its normal operation and the highest critical temperature representative of occurrence of the abnormal condition can fall below the currently prescribed temperature limit, the transformer 12 itself can be assembled compact in size, lightweight and at a reduced cost.
  • the temperature responsive switch 30 is supported sandwiched between the secondary winding 14 and the transformer core 18, no extra fastening element is needed to allow it to be supported and retained in position.
  • the thermostat 30 of a type that will be switched off when the detected temperature attains 200°C and be reset to an ON stage when the detected temperature falls down to 190°C
  • attainment of the temperature at the inner peripheral surface of the coiled secondary winding 14 to 200°C can result in interruption of the power supply to the primary winding 13 to thereby suppress any undesirable temperature increase and, accordingly, the normal operating temperature of the transformer 12 will not exceed the prescribed limit of 200°C and, even in the event of occurrence of the abnormal condition such as failure of the cooling fan 3 to operate normally, the temperature of the transformer 12 will not increase to a value higher than the prescribed limit of 250°C.
  • the temperature responsive switch 30 is effective to detect the temperature as close to the highest possible temperature of the transformer 12 as possible accurately and with minimized localized variation that may occur depending on the position where the temperature responsive switch 30 is disposed.
  • the temperature responsive switch 30 detects the temperature at a region between the secondary winding 14 and the transformer core 18 which will attain the highest temperature detects such temperature exceeding a predetermined temperature.
  • the temperature responsive switch 30 connected with the primary winding 13 can be positioned considerably close to the terminal support 40, making it possible to use relatively short lead lines 31 and 32 of the temperature responsive switch 30 that are connected with the terminal support 40 while eliminating the necessity of use of any extra connection terminal element necessary to support the junction 35 between the lead line 13e of the primary winding 13 and the lead line 32 of the temperature responsive switch 30.
  • the transformer 12 since the transformer 12 is mounted in the oven casing 2 in such a manner that a mounting surface of the thermostat 30 can be oriented downstream of the flow of the cooling air, the cooling air will not impinge directly on the temperature responsive switch 30 and, accordingly, the position of the temperature responsive switch 30 will be the area where the highest possible temperature in the transformer 12 may be attained. In other words, the temperature responsive switch 30 can properly detect the temperature of the area of the transformer 12 where the highest possible temperature will be attained.
  • the secondary winding 14 is assumed to attain the highest possible temperature in the transformer 12. However, depending on the design trade-off such as a current or voltage ratio between the primary winding 13 and the secondary winding 14, it may occur that the primary winding 13 will evolve heat of a temperature higher than that evolving in the secondary winding 14. In such case, the temperature responsive switch 30 has to be intervened between the primary winding 13 and the transformer core 18 so that the temperature as close to the highest possible temperature of the transformer 12 as possible can be detected.
  • transformer core has been described including the generally E-shaped core piece and the generally I-shaped core piece.
  • the use may be made of two generally E-shaped core pieces for the transformer core.
  • the present invention can be equally applied to any transformer designed according to a different standard prescribing the different highest permissible operating temperature and the different highest critical temperature.
  • the transformer embodying the present invention is not always limited to the use for driving the magnetron, but may be used in association with any transformer having a higher operating temperature.
  • the transformer embodying the present invention has been described as that employed in the microwave oven.
  • the electronic oven 1 which is an example of electric appliances, includes an oven casing 2 accommodating therein both a magnetron 16, which is an electronic element adapted to be driven by the transformer 12, and a cooling fan 3 for cooling the transformer 12, and wherein the thermostat 30 for the transformer 12 is mounted in the oven casing 2 in such a manner that a mounting surface of the thermostat 30 can be oriented downstream of the flow of the cooling air, i.e., on one side of the transformer 12 remote from the side thereof where the cooling air from the cooling fan 3 impinges, the electric appliance can be assembled compact and lightweight and at a reduced cost owing to compactization of the transformer 12.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Housings And Mounting Of Transformers (AREA)
  • Constitution Of High-Frequency Heating (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
EP20020254013 2002-06-10 2002-06-10 Transformator mit Temperaturdetektor und elektrisches Gerät welches ihn verwendet Expired - Lifetime EP1372165B1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP20020254013 EP1372165B1 (de) 2002-06-10 2002-06-10 Transformator mit Temperaturdetektor und elektrisches Gerät welches ihn verwendet
DE2002605468 DE60205468T2 (de) 2002-06-10 2002-06-10 Transformator mit Temperaturdetektor und elektrisches Gerät welches ihn verwendet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20020254013 EP1372165B1 (de) 2002-06-10 2002-06-10 Transformator mit Temperaturdetektor und elektrisches Gerät welches ihn verwendet

Publications (2)

Publication Number Publication Date
EP1372165A1 true EP1372165A1 (de) 2003-12-17
EP1372165B1 EP1372165B1 (de) 2005-08-10

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EP20020254013 Expired - Lifetime EP1372165B1 (de) 2002-06-10 2002-06-10 Transformator mit Temperaturdetektor und elektrisches Gerät welches ihn verwendet

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EP (1) EP1372165B1 (de)
DE (1) DE60205468T2 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2568768A3 (de) * 2011-09-07 2013-03-27 Samsung Electronics Co., Ltd. Mikrowelle
CN104373970A (zh) * 2014-11-13 2015-02-25 广东美的厨房电器制造有限公司 微波炉
CN111430136A (zh) * 2020-05-06 2020-07-17 深圳市鸿宝电气有限公司 一种干式变压器负载自我诊断保护装置
CN113016046A (zh) * 2018-07-31 2021-06-22 美达系统有限公司 绕组组件

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3675081A (en) * 1970-04-27 1972-07-04 Gen Electric Thermal-overload protective arrangement for inductive devices
US5321572A (en) * 1991-03-28 1994-06-14 Nippon Densen Corporation Transformer bobbin
EP1047086A1 (de) * 1998-01-06 2000-10-25 Kureha Kagaku Kogyo Kabushiki Kaisha Spulenbauteil
GB2352563A (en) * 1999-07-28 2001-01-31 Samsung Electronics Co Ltd High voltage transformer with a temperature sensor mounted in the insulation layer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3675081A (en) * 1970-04-27 1972-07-04 Gen Electric Thermal-overload protective arrangement for inductive devices
US5321572A (en) * 1991-03-28 1994-06-14 Nippon Densen Corporation Transformer bobbin
EP1047086A1 (de) * 1998-01-06 2000-10-25 Kureha Kagaku Kogyo Kabushiki Kaisha Spulenbauteil
GB2352563A (en) * 1999-07-28 2001-01-31 Samsung Electronics Co Ltd High voltage transformer with a temperature sensor mounted in the insulation layer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2568768A3 (de) * 2011-09-07 2013-03-27 Samsung Electronics Co., Ltd. Mikrowelle
CN104373970A (zh) * 2014-11-13 2015-02-25 广东美的厨房电器制造有限公司 微波炉
CN113016046A (zh) * 2018-07-31 2021-06-22 美达系统有限公司 绕组组件
CN111430136A (zh) * 2020-05-06 2020-07-17 深圳市鸿宝电气有限公司 一种干式变压器负载自我诊断保护装置

Also Published As

Publication number Publication date
DE60205468D1 (de) 2005-09-15
DE60205468T2 (de) 2006-02-09
EP1372165B1 (de) 2005-08-10

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