DE2816592A1 - Control circuit for bistable relay - energises relay through thyristor, so that its contacts open shortly before and close shortly after zero crossing - Google Patents

Abstract

Excitation current for the relay coil is supplied by brief closing of a switch. A rectifier diode (1) is in series with a resistor (2) and a capacitor (3), and the relay coil (9) is in series with a thyristor (8), both in parallel with the capacitor (3). The thyristor (8) gate is connected through a gate resistor (7), a voltage divider (5, 6) and a contact (4) to the mains wires. The thyristor (8) ignition instant is adjusted to the relay (9) movable mechanism and excitation coil, so that the relay contacts open 20 to 10 electrical degrees before zero crossing, and close up to 20 electrical degrees after it.

Description

Circuit arrangement for controlling a bistable relay

The invention relates to a circuit arrangement for controlling a bistable relay in which the excitation current is generated by briefly closing a switching element the relay coil energized.

Bistable relays are normally activated by briefly applying AC voltage to the mains actuated. This moves the armature of a magnet system, which is a contact bridge brings into another position (see e.g. DE-OS 20 50 134).

The switching times, based on the sine curve of the Voltage are not defined here. They are somewhere on the voltage curve.

There are also bistable relays for the respective switching status have an electronic memory. This is a query of the voltage curve and otherwise a defined switching time is also possible, but the effort is still there Components very large. For a minimum contact load, the switching times should are close to the zero crossing.

The object of the invention is to close with very few components and opening AC circuits in the vicinity of the zero crossing of the voltage to enable.

The object is achieved according to the invention in that a rectifier diode with a resistor in series with a storage capacitor and the relay coil arranged in series with a thyristor in parallel with the storage capacitor the gate of the thyristor via a gate Resistance over a voltage divider, consisting of two resistors and a push button contact with the Neztlinien is connected, whereby the ignition timing of the thyristor so on the movement mechanism and the excitation coil of the relay is tunable that the Opening of the relay contacts 0 20 ° to 10 ° electrically before the zero crossing and the relay contacts are closed electrically up to 20 ° after the zero crossing.

The arrangement according to the invention is shown in the drawing using a control circuit for a bistable relay in Fig. 1 explained.

In a graphical representation, the sequence is also shown in FIG Processes according to FIG. 1 shown, As FIG. 1 shows, the diode 1 and the resistor 2, a storage capacitor 3 from the positive half-cycle of the mains voltage charged. If the mechanical button 4 is actuated, a current flows through the Resistors 5 and 6.

The resistors 5 and 6 form a voltage divider, its branch point Is connected to the gate of a thyristor 8 via a resistor 7. The voltage divider resistors 5 and 6 are dimensioned so that the gate current the thyristor 8 to a certain Point in time on the positive mains sine wave ignites. This causes the storage capacitor to discharge 3 via the relay coil 9 and the thyristor 8.

From Fig. 2 it can be seen that the voltage at the voltage divider branch point increases as a function of resistors 5 and 6. When the switching threshold is reached of the thyristor 8 this is switched through, the relay coil with the discharge current of the capacitor is excited, and the mechanical movement sequence of the relay follows. This is always the same for the switching behavior, i.e. the times from reaching the response until the contact is opened or the Contacts are also always the same.

With the help of this circuit arrangement, it is possible from the Combination of mechanical movement sequence, excitation values of the relay coil and series resistor Achieve defined switching points al. This results in a very low tendency to sweat, low contact wear and few interfering clicks achieved. Blank page

Claims (1)

Circuit arrangement for controlling a bistable Relay in which the excitation current is generated by briefly closing a switching element energizes the relay coil, characterized in that a rectifier diode (1) with a resistor (2) in series with a storage capacitor (3) and the Relay coil (9) in series with a thyristor (8) in parallel with the storage capacitor (3) is arranged, the gate of the thyristor (8) via a gate resistor (7) via a voltage divider, consisting of two resistors (5 and 6) and a pushbutton contact (4) connected to the power lines, reducing the ignition timing of the thyristor (8) so tunable to the movement mechanism and the excitation coil (9) of the relay is that the opening of the relay contacts 20 ° to 10 ° electrical before the zero crossing and the closing of the relay contacts up to 20 ° electrical after the zero crossing he follows.