DE1000851B - Signal circuit, especially for railway security systems - Google Patents

Description

GERMAN

In signal circuits, especially for railway safety systems, Capacitors are often used, for example, to reduce the waste or to delay pick-up of a relay. It can happen that such a capacitor in the Operation becomes defective or breaks through without this error initially appearing in the circuit sequence annoyingly noticeable, but can be used to maintain a certain signal state the prescribed duration can no longer be observed by the capacitor in question, which is considerable Can pose a risk to traffic.

To avoid these disadvantages, the invention provides for the capacitor between the periods of use To check, it is known to operate the voltage of a capacitor whose charge a relay is supposed to measure when charging. However, this only checks its effective resistance (its insulation), not its capacity. In contrast, according to the invention, there is an ongoing check of the capacitor made in such a way that the same in a known manner in the course of the circuit sequence before its intended purpose becomes effective, initially in the charged state on the parallel connection of a relay with a resistor is switched, the relay and resistor in relation to each other and to the capacitor are designed in such a way that the relay can only be operated if the capacitor is in perfect condition, i.e. if if this has its full nominal capacity, it is just able to attract, but otherwise not to attract comes and thereby the further switching sequence is prevented or a fault message is triggered will.

It is known to use a capacitor as a power source to a relay with a resistor connected in parallel to put, however, the purpose is to keep the response time of the relay with the longer or shorter To put the exposure time of an external process in comparison. It is assumed that the Properties of the capacitor are unchanged. The purpose of the invention, however, is precisely this Properties to be tested by trial loading with precisely set consumers. According to the In accordance with the invention, a test load similar to the payload, namely essentially a relay, is selected as the test load.

The relay, which is used in this way to continuously check the capacitor, can either a relay specially provided for this purpose or a relay that is effective in the circuit be, for example, the relay whose drop is to be delayed by the capacitor to be checked.

Signal circuit, in particular
for railway safety systems

Applicant:

Pintsch Bamag Aktiengesellschaft,
Berlin NW 87, Reuchlinstr. 10-17

Gerhard Schindler, Frankfurt / M.,
has been named as the inventor

The invention is illustrated in more detail in the drawing, for example, which is part of a signal circuit reproduces insofar as this is important for the invention.

When the circuit is idle, the capacitor C to be checked is connected to the DC voltage + / · -. After the switching device has started to work, a relay 1 (not shown) becomes effective at a given moment, the changeover contact 11 of which switches the capacitor C off and on to the relay 2 when the voltage is switched over. A resistor Wl is connected to the relay 2 via an initially closed contact 21 of the relay 2. The capacitor charged to the DC voltage will normally discharge itself through the relay and the resistor, thereby causing the relay to pick up. The resistance and relay data in relation to the capacitance of the capacitor and the voltage of the power source are selected in such a way that the branch current normally flowing through the relay is sure to bring the relay to the pick-up point. The responsive relay 2 can then, for. B. switch off the resistor W 1 with a contact 21 and connect the capacitor C to voltage again with its contact 22, so that if the contact 31 of a relay 3, not shown, is later interrupted, the full charge of the capacitor for the delayed fall of the relay 2 is available stands, which also has additional contacts that intervene in the circuit.

Claims (4)

Patent claims: 1. Signal switching, especially for railway safety systems with a delay counter 60? 756 '"4 capacitor for a relay, characterized in that for continuous checking of the capacitor the same in a manner known per se in the course of the circuit sequence in the charged state on the Parallel connection of a relay and a resistor is switched, with relay and resistor in relation to each other and to the capacitor are designed so that the relay only with perfect condition, d. H. responds to the full nominal capacity of the capacitor. 2. Signal circuit according to claim 1, characterized in that for that to the capacitor relays that can be connected to check this the same relay is used, the drop of which is to be delayed by the capacitor. 3. Signal circuit according to claim 1 and 2, characterized in that the parallel to the relay lying resistance can be switched off by a normally closed contact of the relay. 4. Signal circuit according to claim 1 to 3, characterized in that a working contact of the Relay puts the capacitor back on after checking. Considered publications:
German Patent Nos. 719 744, 765 149. 1 sheet of drawings