DE2612592A1 - AC CONTACTOR WITH WASTE DELAY - Google Patents

Description

Maschinenfabrik Reinhansen Regeneburg, March 24th 1976 Scheubeck Brothers KG. 2Ci> Ma / Gl Regensbürg

AC contactor with dropout delay

The invention relates to an alternating current controlled contactor or relay, as it is in the preamble of the associated Claim 1 is designated in more detail.

A rectifier bridge has already been proposed for such contactors to be provided in Graetz circuit, in whose direct current diagonal the capacitor lies and in the two opposite one Branches are bridged by ohmic or inductive resistances (DT-AS 11 50 141). Here, however, occurs Difficulty on that over the bridging resistances of the two opposite branches of the Graetz circuit a partial discharge of the capacitor must always take place again, so that for the drop-out delay of the to be controlled Contactor cannot use the full capacity of the capacitor. Furthermore, for the process of dropout delay the discharge of the capacitor can only take place via the then effective series connection of the individual resistors. This in turn leads to an impairment of the discharge process of the capacitor, which is important for the drop-out delay.

The object of the invention is to provide a circuit for the drop-out delay which can also be added to the contactor at a later date, independently of an external supply, and which both a full utilization of the capacitance of the capacitor for the process of the drop-out delay, as well as a safe one Discharge of the capacitor allowed during the dropout delay. According to the invention, this object is achieved by the characteristics of claim 1 specified means solved.

The advantages achieved with the invention lie in the achievement of the goal of the task: no external supply for the drop-out delay, subsequent fitting of the contactors with a drop-out delay is possible, the capacity of the

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used capacitor can be fully utilized, more reliable Discharge process of the capacitor in the process of dropout delay.

An embodiment of the invention is shown in the accompanying drawing as a circuit diagram and is described below explained in more detail:

As can be seen from the circuit diagram, the excitation winding RL of the contactor with its terminals a, b is connected to an alternating voltage source WS, which can be switched on or off via a switch S. In parallel with the excitation winding RL lies the series connection of a capacitor C1 and a rectifier D. A protective resistor R1 is connected upstream of both. A thyristor Th is provided parallel to the rectifier, its ignition line L via a reed relay d from an electronic control unit Z, which is also parallel to the excitation winding RL is arranged, can be fed. Another capacitor C 2 is then also connected in parallel with the excitation winding RL upstream resistor R2.

The mode of operation of the arrangement is as follows: When switch S is closed, the excitation winding RL is connected to voltage and, the associated contactor is switched on. The capacitor C1 has been charged via the rectifier D. If the voltage WS now remains absent, this leads to an immediate response of the reed relay d, as a result of which the control electronics Z, which are provided with a corresponding memory, trigger the thyristor Th initiates, so that the capacitor C1 through this thyristor Th can discharge, as a result of which a holding current then occurs in the field winding Rl. Since the thyristor th from the control electronics Z can only get a brief ignition pulse, it is necessary that the conductive state immediately of the thyristor starts maintaining the current. Since now, on the other hand, the inductance of the excitation winding RL this Can delay current, a further capacitor C2 with resistor R2 is also provided in parallel to the excitation winding RL, the for a quick start of the discharge current right from the start

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of the capacitor C1 ensures that the means of the short Pulse triggered thyristor Th as a result of this immediately onset current does not return to the blocking state can fall back. The discharge current thus also flowing via the excitation winding RL leads in a known manner to the drop-out delay of the associated contactor.

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Claims (2)

-Jf- Claims ./ AC-controlled, drop-out delayed contactor or relay, the field winding of which is connected in series with a rectifier and a capacitor is bridged, characterized in that a thyristor in parallel with the rectifier (D) (Th) is connected, which by means of a likewise parallel to the excitation winding (RL), a Control electronics (Z) containing capacitance can be ignited. 2. Contactor or relay according to claim 1, characterized in that in parallel with the excitation winding (RL) another capacitor (C2) is connected in series with a resistor (R2). 709840/0179 ORIGINAL INSPECTED