EP0981265B1 - Mikrowellenherd versehen mit eine Sicherungseinrichtung für den Hochspannungstransformator - Google Patents

Mikrowellenherd versehen mit eine Sicherungseinrichtung für den Hochspannungstransformator Download PDF

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Publication number
EP0981265B1
EP0981265B1 EP99302489A EP99302489A EP0981265B1 EP 0981265 B1 EP0981265 B1 EP 0981265B1 EP 99302489 A EP99302489 A EP 99302489A EP 99302489 A EP99302489 A EP 99302489A EP 0981265 B1 EP0981265 B1 EP 0981265B1
Authority
EP
European Patent Office
Prior art keywords
voltage transformer
rectifying
voltage
power supply
overcurrent protection
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
EP99302489A
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English (en)
French (fr)
Other versions
EP0981265A1 (de
Inventor
Young Cheol Ko
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.)
Samsung Electronics Co Ltd
Original Assignee
Samsung Electronics 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 Samsung Electronics Co Ltd filed Critical Samsung Electronics Co Ltd
Publication of EP0981265A1 publication Critical patent/EP0981265A1/de
Application granted granted Critical
Publication of EP0981265B1 publication Critical patent/EP0981265B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H05B6/64—Heating using microwaves
    • H05B6/66—Circuits
    • H05B6/68—Circuits for monitoring or control
    • 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

Definitions

  • the present invention relates to a microwave oven including a high-voltage transformer and overcurrent protection means for protecting the high-voltage transformer from an initial overcurrent condition, the overcurrent protection means comprising a resistor in series between a power in terminal and a primary winding of the high-voltage transformer and a relay in parallel with the resistor.
  • FIG. 2 is a circuit diagram of a known power control circuit of a microwave oven.
  • the microwave oven has a power supply part 101, a high-voltage transformer 109 for stepping up the normal voltage from the power supply part 101 to a high level and a magnetron 110 for generating microwaves which is powered from the output of high-voltage transformer 101.
  • a thermal switch 103 responsive to the temperature in the cooking chamber (not shown), a door switch 105 responsive to opening and closing of the oven door (not shown) and a monitor switch 107 for controlling supply of power to said high-voltage transformer 109 on the basis of the states of the thermal and door switches 103, 105 are connected between the power supply part 101 and the high-voltage transformer 109.
  • the thermal switch 103 is disposed between the power supply part 101 and the monitor switch 107
  • the door switch 105 is disposed between the power supply part 101 and the high-voltage transformer 109.
  • An overcurrent protection relay 121 connected in series between the door switch 105 and the high-voltage transformer 109.
  • An overcurrent protection resistance unit 123 is connected in parallel with the overcurrent protection relay 121.
  • the coil 115 of the relay 121 is connected in parallel with the monitor switch 107.
  • the monitor switch 107 has a bypass connecting node 131 and a branch connecting node 133.
  • the bypass connecting node 131 is a point on a bypass line 130 disposed between the relay coil 115 and the high-voltage transformer 109, for supplying power from said power supply part 101 to the bypass line 130.
  • the branch connecting node 133 is a point on the line connected to the high-voltage transformer 109 for supplying power to the relay coil 115 and the high-voltage transformer 109.
  • the thermal and door switches 103, 105 are closed.
  • the moving contact of the monitor switch 107 contacts the branch connecting node 133 and the power supply part 101 is connected in series with the overcurrent protection resistance unit 123 and the high voltage transformer 109. Therefore, the initial current supplied from said power supply part 101 is reduced by the overcurrent protection resistance unit 123.
  • the relay coil 115 is energised and the overcurrent protection relay 121 is closed.
  • a microwave oven according to the present invention is characterised by rectifying means for rectifying current input to the oven for energising the coil of the relay.
  • an oven according to the present invention includes smoothing means for smoothing the output of the rectifying circuit.
  • the rectifying means comprises a bridge rectifier and the smoothing means comprises a capacitor in parallel with said coil.
  • resistor means is included for reducing the voltage of the current to be rectified by the rectifying means.
  • a monitor switch having a first state in which a power supply line is disconnected from the high-voltage transformer and connected to a by-pass line which by-passes the rectifying means and a second state in which said power supply line is connected to the high-voltage transformer and disconnected from said by-pass line
  • a microwave oven has a power supply part 1, a magnetron 10 for generating microwaves and a high-voltage transformer 9 for stepping up mains voltage to a high level.
  • a thermal switch 3 responsive to the temperature in the cooking chamber (not shown) and a door switch 5 responsive to opening and closing of the oven door (not shown) and a monitor switch 7 for controlling the supply of power to the high-voltage transformer 9 on the basis of the states of the thermal and door switches 3, 5 are connected between said power supply part 1 and the high-voltage transformer 9.
  • the thermal and door switches 3, 5 are connected in series between the power supply part 1 and the high-voltage transformer 9.
  • the power control device further comprises an overcurrent protection relay 21 disposed in series between the thermal and door switches 3, 5, an overcurrent protection resistance unit 23 connected in parallel with the overcurrent protection relay 21, and a rectifying part 8 for rectifying the current from the power supply part 1.
  • the rectifying part 8 has at least one voltage-controlled resistor 13, a bridge diode 11 connected to said voltage-controlled resistor 13, a capacitor 17 connected in parallel with the bridge diode 11, and the coil 15 of the overcurrent protection relay 21.
  • the monitor switch 7 has a bypass connecting node 31 and a branch connecting node 33.
  • the bypass connecting node 31 is a point on a bypass line 30 disposed between the relay coil 15 and the high-voltage transformer 9.
  • the branch connecting node 3 is a point on the line connected to the high-voltage transformer 9 for supplying power to the relay coil 15 and the high-voltage transformer 9.
  • the thermal and door switches 3, 5 are closed.
  • the moving contact of the monitor switch 7 contacts the branch connecting node 33. Because the current supplied from the power supply part 1 passes through the overcurrent protection resistance unit 23, the initial current is reduced and at the same time, the current branched to said rectifying part 8 is rectified so that stable current is supplied to the relay coil 15. This causes the overcurrent protection relay 21 to close shortly after current begins to flow through the primary winding of the high-voltage transformer 9.
  • the high-voltage transformer is protected from an initial overcurrent condition and the overcurrent protection relay is controlled by induction energy generated from the relay coil by use of a stable current.
  • the inrush relay is controlled by a stable current, and thus, the reliability is improved.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
  • Emergency Protection Circuit Devices (AREA)

Claims (5)

  1. Mikrowellenherd mit einem Hochspannungstransformator (9) und einem Überstromschutzmittel (8, 21, 23) zum Schützen des Hochspannungstransformators vor einem Anfangsüberstromzustand, wobei das Überstromschutzmittel einen Widerstand (23), der zwischen einem Stromeingangsanschluss und einer Primärwicklung des Hochspannungstransformators (9) in Reihe geschaltet ist, und ein Relais (21) umfasst, das mit dem Widerstand (23) parallel geschaltet ist, gekennzeichnet durch ein Gleichrichtmittel (11) zum Gleichrichten des Eingangsstroms in den Herd zum Erregen der Spule (15) des Relais (21).
  2. Herd nach Anspruch 1 mit einem Glättungsmittel (17) zum Glätten des Ausgangs der Gleichrichterschaltung (11).
  3. Herd nach Anspruch 2, bei dem das Gleichrichtmittel (11) einen Brückengleichrichter (11) umfasst und das Glättungsmittel (17) einen Kondensator (17) umfasst, der parallel zu der genannten Spule geschaltet ist.
  4. Herd nach Anspruch 1, 2 oder 3 mit einem Widerstand (13) zum Reduzieren der Spannung des von dem Gleichrichtmittel (8) gleichzurichtenden Stroms.
  5. Herd nach einem der vorherigen Ansprüche, umfassend einen Überwachungsschalter (7) mit einem ersten Zustand, in dem eine Stromversorgungsleitung vom Hochspannungstransformator (9) getrennt und mit einer Umgehungsleitung (30) verbunden ist, die das Gleichrichtmittel (11) umgeht, und einem zweiten Zustand, in dem die genannte Stromversorgungsleitung mit dem Hochspannungstransformator (9) verbunden und von der genannten Umgehungsleitung (30) getrennt ist.
EP99302489A 1998-08-20 1999-03-30 Mikrowellenherd versehen mit eine Sicherungseinrichtung für den Hochspannungstransformator Expired - Lifetime EP0981265B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR3373898 1998-08-20
KR1019980033738A KR100271362B1 (ko) 1998-08-20 1998-08-20 전자렌지의 전원제어장치 및 전원제어방법

Publications (2)

Publication Number Publication Date
EP0981265A1 EP0981265A1 (de) 2000-02-23
EP0981265B1 true EP0981265B1 (de) 2004-06-30

Family

ID=19547701

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99302489A Expired - Lifetime EP0981265B1 (de) 1998-08-20 1999-03-30 Mikrowellenherd versehen mit eine Sicherungseinrichtung für den Hochspannungstransformator

Country Status (3)

Country Link
EP (1) EP0981265B1 (de)
KR (1) KR100271362B1 (de)
DE (1) DE69918380T2 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20010081569A (ko) * 2000-02-16 2001-08-29 윤종용 전자렌지의 전원제어장치
CN103795050B (zh) * 2012-10-31 2017-03-15 中兴通讯股份有限公司 高压保护电路、高压保护方法及电源

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1239789A (en) * 1968-10-31 1971-07-21 Dysona Ind Ltd Improvements relating to microwave ovens
DE2050989C3 (de) * 1970-10-12 1978-07-27 Matsushita Electric Industrial Co., Ltd., Kadoma, Osaka (Japan) Hochfrequenz-Heizanlage
JPS57154789A (en) * 1981-03-20 1982-09-24 Matsushita Electric Ind Co Ltd High frequency heater
KR19990002105A (ko) * 1997-06-19 1999-01-15 배순훈 기계식 전자렌지의 돌입전류 방지회로

Also Published As

Publication number Publication date
KR20000014346A (ko) 2000-03-06
DE69918380D1 (de) 2004-08-05
EP0981265A1 (de) 2000-02-23
KR100271362B1 (ko) 2000-11-01
DE69918380T2 (de) 2005-08-11

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