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1. (WO1987003429) APPARATUS AND METHOD FOR PROTECTING AN ELECTRICAL CIRCUIT
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1987/003429 International Application No.: PCT/US1986/000542
Publication Date: 04.06.1987 International Filing Date: 19.03.1986
IPC:
H02H 3/50 (2006.01) ,H02H 7/08 (2006.01)
H ELECTRICITY
02
GENERATION, CONVERSION, OR DISTRIBUTION OF ELECTRIC POWER
H
EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
3
Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition, with or without subsequent reconnection
50
responsive to the appearance of abnormal wave forms, e.g. ac in dc installations
H ELECTRICITY
02
GENERATION, CONVERSION, OR DISTRIBUTION OF ELECTRIC POWER
H
EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
7
Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
08
for dynamo-electric motors
Applicants:
CATERPILLAR INDUSTRIAL INC. [US/US]; 5960 Heisley Road Mentor, OH 44060, US
Inventors:
BAUMGARTNER, Kenneth, A.; US
PICKERING, William; US
Agent:
MUIR, Robert, E. @; Caterpillar Tractor Co. 100 Northeast Adams Street Peoria, IL 61629-6490, US
Priority Data:
803,28502.12.1985US
Title (EN) APPARATUS AND METHOD FOR PROTECTING AN ELECTRICAL CIRCUIT
(FR) APPAREIL ET PROCEDE DE PROTECTION D'UN CIRCUIT ELECTRIQUE
Abstract:
(EN) Motor control systems having solid-state components are commonly used on industrial vehicles such as lift trucks. Such solid-state components are easily damaged by excessive ''ripple'' voltages. The subject invention includes a power supply (12) for supplying direct current to a motor circuit, wherein the direct current has a nominal direct current voltage value and as associated ''ripple'' voltage component. A pulse control circuit (30) supplies current pulses from the power supply (12) to a motor (18). A sensing device (38) controllably produces a fault signal in response to the amplitude of the ''ripple'' voltage component exceeding a predetermined maximum value. An override circuit (58) receives the fault signal and responsively modifies the current pulses delivered from the power supply (12) to the associated motor (18).
(FR) Des systèmes de commande de moteur comprenant des composants solides sont communément utilisés sur des véhicules industriels tels que des chariots élévateurs. De tels composants solides sont facilement endommagés par des tensions d'ondulation excessives. L'objet de la présente invention comprend une source électrique (12) alimentant un circuit de moteur en courant continu, lequel comprend une valeur de tension de courant continu nominale et une composante de tension d'ondulation associée. Un circuit de commande d'impulsions (30) fournit des impulsions de courant à un moteur (18) à partir de la source électrique (12). Un dispositif de détection (38) produit un signal de défaut réglable en réponse à l'amplitude de la composante de tension d'ondulation excédant une valeur maximum prédéterminée. Un circuit de dépassement (58) reçoit le signal de défaut et modifie en conséquence les impulsions de courant fournies par la source électrique (12) au moteur (18) associé.
Designated States: JP, KR
European Patent Office (DE, FR, GB, SE)
Publication Language: English (EN)
Filing Language: English (EN)
Also published as:
EP0247059KR1019880701029