DE1070240B - - Google Patents

Description

The invention relates to a circuit arrangement for reversing a relay at a defined time Query times in which the relay to be reversed has at least one winding that has a bistable flip-flop can be pre-excited, as well as a winding, which is arranged in a query circuit is and whose power flow is changed briefly for interrogation, and which in the interrogation circuit arranged A winding of the relay regardless of the pre-excitation the assumed position of the to be reversed Relay is maintained until the next query time.

In telecommunications technology, the task is often to solve a relay by a control current for a to pre-excite its two positions, but not immediately to the relay armature in the one given by the control current Position to follow, but to keep locked until a certain query time. These Task can be done in a known manner by a relay with a pre-excitation winding, which is in the control circuit is switched on, and release a holding winding, the power flow of which outweighs the pre-excitation and which is switched off briefly at the query times. Stand for the control of the relay no control currents, but only short-term control voltages are available, so the pre-excitation of the relay to be controlled via a monostable or bistable trigger circuit. But this control has the following disadvantage:

Aif the excitation in the holding winding is briefly interrupted during the interrogation times, this is effected this power flow change in the pre-excitation winding an induction voltage, which under certain circumstances the flip-flop reverses unintentionally, so that the actual caused by the control voltage Setting of the flip-flop circuit and thus the corresponding pre-excitation is nullified.

The invention is now based on the object of creating a circuit arrangement which has this disadvantage does not have. This object is achieved according to the invention in that with the pre-excitation winding a rectifier is connected in series and in parallel with it and the rectifier and a resistor the rectifier has such a polarity that it has an influence on the trigger circuit by the Queries caused by transformer reaction in the pre-excitation winding prevented voltage.

In this way, according to the invention, the flip-flop used to control the relay cannot be used be unintentionally reversed, and the setting brought about by the control voltage remains in any case the toggle switch also during the query? obtain.

Circuit arrangement for reversing
of a relay at defined times
Query times

Applicant:
Siemens & Halske Aktiengesellschaft,
Berlin and Munich,

Munich 2, Wittelsbacherplatz 2

Dipl.-Phys. Hans Neuss, Munich, has been named as the inventor

It is already known in relay monitoring circuits about the excitation winding of a relay to connect a rectifier in parallel. In this type of circuit, however, the rectifier only has that Task of preventing arousal even during certain times. An inductive reaction the other relay winding is not switched off.

Details of the invention emerge from the exemplary embodiment.

In the figure, for. B. a polarized relay A with the three AA ^ windings I, II and III. which can be controlled by brief pulses applied to terminals 571 and St2. The windings I and II of the relay A are pre-excitation windings and are in this example via a bistable trigger circuit TFl / TF2 depending on their position. ie working or rest position, excited alternately, while winding III of the relay Λ is the holding winding. The power flow ratio of the pre-excitation windings to the main winding is dimensioned so that the armature ο of the relay A as long as the relay A is excited via its winding III. remains in its respective position and only when the interrogation contact k interrupts the excitation of the holding winding can it be reversed into the position corresponding to the pre-excitation. By L ^T m steering the armature a into the position corresponding to the pre-excitation, the polarity of the power flow of the holding winding is reversed in preparation so that after the brief opening of the interrogation contact k , the holding winding also receives a flow that supports the pre-excitation.

The AA ⁷ ijkungs \ veise the circuit is described in detail as follows: Normally such blocks. B. the transistor

Claims (3)

1 TF1, while transistor TF2 conducts. An emitter-collector current (Ull TF2, Gr 3, All or R4, 0) and an emitter-base current (Ul, TF2, R2, Rl or Grl, AI, Ο) flows through the transistor TF2. The emitter-collector current gives the Re-Iais A via its winding II a pre-excitation acting on the isolating side, which is initially supported by the excitation of the holding winding III of the relay Λ, which is also acting on the isolating side (+ TB1 a in the isolating layer T, AIII, k, O). The sign-side excitation in winding I of the relay yi caused by the low emitter-base current is negligible. In the idle state, the base of the transistor TF1 is more positive than the emitter as a result of the potential tapped off by the voltage divider R5 / R6, so that this transistor blocks. If the base of the transistor TFl becomes more negative than the emitter due to a control pulse applied to the terminal St2 or a brief voltage change, the bistable flip-flop switches in a known manner from its rest position to its working position, and the transistor TFl conducts, while the transistor TF 2 now blocks . As a result, the relay A now receives a pre-excitation (+ U1, TF1, Gr 1, AI, O) acting on the sign side via its winding I, but this cannot affect the position of the armature 0, since the excitation of the holding winding III, which acts on the isolating side, predominates . If the interrogation contact k is now opened for the purpose of interrogation, and the excitation of the holding winding acting on the isolating side is briefly interrupted, then the armature a is moved into the character position Z under the influence of the pre-excitation of the winding I on the character side. After the interrogation contact k is closed, the holding winding III is then also excited on the character side (- TB, a in character position Z, AIII, k, O). By interrupting the current flow in the holding winding III when the interrogation contact k opened, a voltage was induced in the winding I which counteracts the emitter-collector current flowing through the transistor TF1. So that the current flowing through the transistorTFl does not drop to zero due to the counteracting voltage induced in winding I by interrupting the excitation in winding III and the bistable flip-flop circuit unintentionally flips back from its working position to its rest position as a result of this transformational reaction, whereby the query would be falsified, according to the invention, the pre-excitation winding I of the relay A is connected in series with a rectifier Grl and a resistor R1 is connected in parallel to the pre-excitation winding I and the rectifier Grl. In this way, according to the invention, the emitter-collector current is prevented from falling to zero, since the emitter-collector current can flow through the resistor Rl and the induced voltage itself through completely regardless of the magnitude of the voltage induced in the relay winding I the rectifier Grl is shut off. In the case of voltages induced in the relay winding AI which are directed in such a way that they would promote the emitter-collector current, i.e. a risk of destruction to the transistor TF1 due to excessive current, the auxiliary power source - UZ according to the invention provides for a corresponding equipotential bonding via the rectifier Gr 2. In the same way as the pre-excitation winding I of the relay A, according to the invention, the or-excitation winding A II is protected by the rectifiers Gr3 and Gr4 as well as the resistor RA and the auxiliary power source - (73. The Resistors R2 and R3 are used in a known way to generate the base voltage of the transistor TF2. The capacitors C1 and C2 accelerate the flip-flop process in a known manner. The invention is not limited to bistable flip-flops, but can also be used in full with monostable flip-flops. Likewise, the circuits in the context of the invention can also be used in place of the Tra nsistors be wired with tubes. ! 1AT v. N T Λ SS IM! CCH M: 1. Circuit arrangement for reversing a relay at time-defined interrogation times, in which the relay to be reversed has at least one winding which can be pre-excited via a flip-flop circuit, as well as a further winding which is arranged in an interrogation circuit and whose power flow is briefly changed for interrogation and the winding of the relay arranged in the interrogation circuit independently of the pre-excitation maintains the assumed position of the relay to be reversed up to the next interrogation time, characterized in that a rectifier (Grl or Gr3) in series and with the pre-excitation winding (AI, AU) parallel to it and the rectifier, a resistor (Rl or R 4) is connected and the rectifier (Grl or Gr3) has such a polarity that it influences the flip-flop circuit (TF1, TF2) by the transformer reaction in the pre-excitation winding (I, II) prevents induced voltage. 2. Circuit arrangement according to claim 1, characterized in that the common switching point of the pre-excitation winding (I, II) connected in series with the rectifier (Grl or Gr3) via a further rectifier (Gr2 or Gr4) to a negative auxiliary power source (U3) is turned on. 3. A circuit arrangement according to claim 1, characterized in that in addition to the interrogation coil (III) in the interrogation circuit or a query contact (k) and is spaced from the relay (A) to be actuated changeover (a) and the changeover contact (a) is capable of to connect the query circuit on the one hand to the positive and on the other hand to the negative pole of a power source. Considered publications:
Swiss patent specification No. 296 196. 1 sheet of drawings © 909 687/95 11.59