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1. (WO1979000619) SPEED CONTROL DEVICE FOR ASYNCHRONOUS MOTORS
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1979/000619 International Application No.: PCT/SE1979/000030
Publication Date: 06.09.1979 International Filing Date: 13.02.1979
IPC:
H02P 27/02 (2006.01)
H ELECTRICITY
02
GENERATION, CONVERSION, OR DISTRIBUTION OF ELECTRIC POWER
P
CONTROL OR REGULATION OF ELECTRIC MOTORS, GENERATORS, OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS OR REACTORS OR CHOKE COILS
27
Arrangements or methods for the control of ac-motors characterised by the kind of supply voltage
02
using supply voltage with constant frequency and variable amplitude
Applicants:
Inventors:
Priority Data:
780164013.02.1978SE
Title (EN) SPEED CONTROL DEVICE FOR ASYNCHRONOUS MOTORS
(FR) DISPOSITIF DE CONTROLE DE VITESSE POUR MOTEURS ASYNCHRONES
Abstract:
(EN) Current control for asynchronous motors of short-circuit type, for multiphase, usually threephase, operation. In series with the stator windings (La, Lb, Lc) separate switches (10) are coupled, preferably triacs or pairs of thyristors, Each switch is controlled by its own control circuit (A, B, C) which ignites the switches at points in time determined by the zero crossings for reference voltages which are obtained from individual voltage dividers (R1, R2). According to a preferred embodiment, using triacs, their ignition is effected via reversed diodes, which should not be too fast. A suitable circuit for achieving braking with such a controlled motor is also shown. The principle for this is essentially that two of the motor phase windings each have a pair of different control circuits, whose reference phases are determined, for the first circuit in each pair, by voltage division between a first one of the phases connected to the winding in question and one of the two other phases, while the other control circuit in the pair receives its reference phase from said first phase and the remaining phase of said two other phases. A pulse determining circuit is coupled to one of these control circuits in the pair and detects the absence of control pulses, meaning that the motor is running too fast, and then emits a relay control signal, whereby, firstly, two phases are interchanged, and secondly, the second control circuit in each pair is coupled in, resulting in a braking current feed counteracting the direction of movement of the motor, the recouplings reverting to their original arrangements when control pulses are again received.
(FR) Commande de courant pour les moteurs asynchrones du type a court-circuit fonctionnant en plusieurs phases, habituellement en triphase. Des interrupteurs separes (10), de preference des triacs ou des paires de thyristors sont couples en serie avec les enroulements du stator (La, Lb, Lc). Chaque interrupteur est commande par son propre circuit de commande (A, B, C) qui actionne les interrupteurs a des moments determines par les passages a la valeur nulle des tensions de reference qui sont obtenues a partir de diviseurs de tension separes (R1, L2). Selon un mode d"execution prefere dans lequel sont utilises des triacs, ceux-ci sont actionnes via des diodes inverses, qui ne devraient pas etre trop rapides. Un circuit convenant pour effectuer un freinage a l"aide d"un moteur ainsi commande est egalement decrit. Le principe en est que deux des enroulements de phase du moteur possedent chacun une paire de circuits de commande differents, dont les phases de reference sont determinees, pour le premier circuit de chaque paire, par la division de tension entre une premiere des phases connectees a l"enroulement en question et l"une des deux autres phases, alors que l"autre circuit de commande de la paire recoit sa phase de reference de ladite premiere phase et de la phase restante des deux autres phases. Un circuit de determination d"impulsions est couple a l"un des circuits de commande de la paire et detecte l"absence d"impulsion de commande, ce qui signifie que le moteur tourne trop vite, et emet un signal de commande de relais, ce qui entraine en premier que deux phases sont interchangees et, en second, que le deuxieme circuit de commande de chaque paire est couple, ce qui se traduit par un courant de freinage qui agit contre le sens de rotation du moteur, les couplages revenant a leur disposition initiale lorsque des impulsions de commande sont a nouveau detectees.
Designated States:
Publication Language: English (EN)
Filing Language: English (EN)