DE682814C - Periodic DC switch, especially pendulum inverter - Google Patents

Description

Periodic DC switch, especially pendulum inverter It is already known; for spark quenching when switching a DC circuit on and off a series connection of a rectifier G and a capacitor C in parallel with the Switch S (Fig. I) or to consumer V (Fig. 2). The anode of the rectifier is the positive pole when connected in parallel to the switch, when connected in parallel to the consumer facing the negative pole of the DC voltage source B.

With this arrangement, the voltage jump at the switch is at the Switch opening through the capacitor. Added, since the rectifier is then low Has resistance, while when the switch closes there is no noticeably large discharge or discharge point. Charging current can flow through the capacitor and thus also through the switch, because the rectifier then has an opposing voltage and this is a very high one Represents resistance. In this way, the opening spark can be strong. to decrease, without the closing spark becoming stronger in a corresponding manner.

When the switch is closed, the capacitor slowly discharges (resp. charges slowly to the battery voltage in the circuit according to Fig. 2) the blocking resistance of the rectifier G, at whose cathode a damz opposite Anode positive voltage. In the event that the blocking resistance of the rectifier is so high that the discharge is too slow, d. H. so, slowly, that it has not yet ended in the normal closing time of the switch, As shown in Fig. i and 2, a high ohmic resistance parallel to the rectifier R, by which the discharge time constant is determined. This can are also parallel to the capacitor.

Such spark extinguishing arrangements are also already for periodic switches known for automatic speed controllers, The invention relates refer to the application of this arrangement to a periodic DC switch, in particular pendulum inverters, where the minimum movable contact pole alternates is brought into contact with two fixed opposite poles, and consists in the fact that the fixed opposite poles via a capacitor each and via a common one with each of the capacitors in series rectifier with the movable contact pole are connected.

The advantage of the invention is that instead of several rectifiers, mostly because of the necessary low resistance in the lead phase Have to be large, only one rectifier to extinguish several spark Contacts causes.

In the case of pendulum inverters with a fixed closing time -can you can optimally dimension the quenching circuit for both contacts by adding the capacitors makes the same size and dimensioned them and the rectifier so that the discharge time constant that from the capacitor and the possibly artificially reduced blocking resistance of the rectifier's existing extinguishing circuit is smaller than the time during which the contacts are closed (closing time).

An embodiment of the invention is shown in Fig.3 with a pendulum inverter. The oscillating spring F connects the positive terminal of the battery B alternately via the two opposite poles G and G2 to the outer ends of the primary winding of the transformer T, the center tap of which is connected to the negative terminal of the battery. The opposing poles are also via a respective capacitor C1 and C2 and a single rectifier G is connected directly to the positive terminal of the battery. The rectifier capacitor chains are thus similar to the circuit according to Fig. I parallel to the switching contacts, but only a single rectifier needs to be used. The ohmic resistance R; which is parallel to the rectifier 0, reduces its blocking resistance.

With a symmetrical design of the pendulum inverter, the capacitors are C and C2 are expediently dimensioned to be the same size. Your size as well as the size of the Rectifier G 'and the parallel resistor R is then chosen so that the Time constant of the extinguishing circuits for the closing time in which the capacitors are discharged through the blocking resistor of the rectifier, is less than the closing time, which in the present case is a fixed size.

Claims (1)

PATENT CLAIMS: i. Periodic DC switch, in particular I? Endel inverter; in which one movable contact pole alternates with two fixed ones Opposite poles is brought into contact, characterized in that the fixed opposite poles (G1 and -G2) each via a capacitor (Cl or C2) and via a common, with each of the capacitors in series rectifier (G) with the movable one Contact pole (F) are connected. z. Periodic DC switch according to claim i, characterized in that with the same closing time of the contacts, the capacitors the same size and they and the rectifier are dimensioned such that the time constant the discharge of the from the capacitor and, if necessary, by an additional, Ghm's resistance lying parallel to the rectifier or the capacitors reduced blocking resistance of the rectifier existing arcing circuit smaller is than the closing time of the contacts.