RELAY CONTACT WELDING DETECTION METHOD AND APPARATUS

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(11)

EP 1 610 355 A8

(12)	CORRECTED EUROPEAN PATENT APPLICATION
	published in accordance with Art. 158(3) EPC

(15)	Correction information:
	Corrected version no 1 (W1 A1)

(48)	Corrigendum issued on:
	15.03.2006 Bulletin 2006/11

(43)	Date of publication:
	28.12.2005 Bulletin 2005/52

(21)	Application number: 04724176.5

(22)	Date of filing: 29.03.2004

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International Patent Classification (IPC):

H01H 47/00^(1968.09)

(86)	International application number:
	PCT/JP2004/004410

(87)	International publication number:
	WO 2004/088696 (14.10.2004 Gazette 2004/42)

(84)	Designated Contracting States:
	DE FR IT

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Priority:

31.03.2003 JP 2003095045

(71)	Applicant: NEC Lamilion Energy, Ltd.
	Sagamihara-shi Kanagawa 229-1198 (JP)

(72)	Inventor:
	TEZUKA, Kazunari, NEC Lamilion Energy, Ltd. Sagamihara-shi, Kanagawa 229-1198 (JP)

(74)	Representative: Stork, Ute
	Patentanwälte Wenzel & Kalkoff Postfach 73 04 66 D-22124 Hamburg D-22124 Hamburg (DE)

(54)	RELAY CONTACT WELDING DETECTION METHOD AND APPARATUS

(57) A method for detecting a welding of a relay contact in a circuit having a DC power supply; a load circuit; a first main relay and a second main relay respectively inserted in a pair of power supply lines disposed between the DC power supply and the load circuit; and a precharge relay which is provided in parallel to the contact of the first main relay has the step of carrying out a sequence control to each of the relays (11, 12, 13) while measuring voltage across both ends of the load circuit (16) when shifting from a normal operation state in which a first main relay (11) and a second main relay (12) are controlled to be on and the precharge relay (13) is controlled to be off to a suspension state in which each of the relays (11, 12, 13) are controlled to be off. The welding of the relay contact of the first main relay (11) and the second main relay (12) is determined independently and separately from a correspondence between the proceeding of the sequence and the measured voltage.