Abstract:
The device is intended to the control of an electromagnet comprising a coil (L) connected to a monoarch periodic current supply source, through a controllable switch (TH). Said switch (TH) is controlled by a control circuit comprising a detection member for detecting times crossover of the voltage of the source (R3, D4, IN1, R4, C3) and a switching device (FC) controlled by said detection member in order to deliver to the switch (TH) a closing signal upon the detection of a crossover time which follows the energization control order of the coil (L). The invention applies particularly to contactors and to electro-valves.
Abstract:
The device is used for the control of an electromagnet of which the coil (L) is connected to an alternating current supply source through a switch (T) controlled by a control circuit. Said control circuit comprises a member for determining the zero voltages of the alternating current (R4, C3, D3, IN1, C4, R6, IN2), a delay element adjusted to obtain a delay time which corresponds to the privileged control angle of the electromagnet and a switching device (FL) controlled by the delay element in order to deliver to the switch (T), following a control order, a control signal retarded by said delay time. The invention applies particularly to contactors and to electrovalves.
Abstract:
The apparatus according to the invention comprises a power part (20) provided with a power switch having two controlled semiconductors (TH1, TH2) of which the power terminals are connected to an alternating source in series with the load, a control circuit (30) for controlling said switch and which comprises a first control switch sensitive to an input signal and connected to the trigger (G1, G2) of the power semiconductors (TH1, TH2) via a rectifier bridge (33). The control switch is a field effect transistor (I1) of which the drain-source path is connected to the continuous terminals (31, 32) of the rectifier bridge (33) via a current limiter (L). To the grid (G) of the transistor (I1) is applied a control signal formed as a function of an input signal presented at the terminals (36, 37) of a galvanic isolation member (38). The apparatus according to the invention may be used as a unipolar or multipolar static contactor or relay for alternating currents.