SU28568A1 - Device to protect the alternator from short circuit - Google Patents

Description

It is well known to use, by means of a shunt or transformer, the current of the generator power circuit to act on the regulating element included in the excitation circuit of this generator. As said element, for example, electron tubes are used, the filament of which is powered by a current of a controlled circuit. Similarly, it is known to use thermal current lamps included in the generator's excitation circuit as current and voltage regulators, with either a grid or a heating electrode being connected to a power circuit. The present invention relates to a device for protecting alternators from short-circuiting, in which the above-mentioned control principle is used for demagnetizing and re-magnetizing its inductors, and consists in that the control is carried out by differentially operating field windings.

In FIG. 1 shows a diagram of the proposed device for a low power generator; FIG. 2-complicated circuit as applied to a powerful generator.

The alternator winding G consists of two parts: a magnetizing

windings f / i and demagnetizing (L The number of the amperages of the latter is small compared to the amperages of the first winding. In series with the winding f / g and parallel to the winding i / j, the kenotron is turned on. , and can be shunted by resistance Gz, and in the excitation circuit of the alternator there is an adjusting rheostat Gg ,.

Normally, the filament of the kenotron is not heated and a completely insignificant current passes through its circuit. As a result, almost all of the excitation current passes through the winding (Jj, did not branch off to the kenotron. With a short connection in the power network, the current in the circuit of the kenotron filament increases dramatically, the current in the kenotron increases and the coil current Ui decreases and the windings 2 increase. Excitation the generator will begin to decrease and, finally, will become negative, and at the same time the current in the power circuit will decrease.

FIG. 2 depicts a somewhat complicated circuit diagram of a device assigned to protect a powerful alternator. The alternator G, supplied with excitation windings Ui and acting in opposite directions, is connected to the three-phase current line through the disconnector Tj .. Tru. a current transformer with a grounded zero point is fed through the rheostats of filaments of three in parallel; interconnected kenotrons KI, Kzt Kz connected to the circuit of a direct current source E (battery), in series with resistance Ri, smaller than RI- Ion mercury KI and YZ b1; each has its own anode circuit (anodes i A) in series with the windings f / i, / 2 of Generator G. Coils U and U-, are fed from DC sources D to Oz to one poles of which through rheostats TI and g-2 Auxiliary anodes 1 AI and B AZ are not used. To the other poles of these sources irksoed nekm mercury cathodes PI and P-.

When the alternator current is normal, the glow of the kenotron threads is insignificant and the resistance Ri will hardly be bridged. The potential difference between the cathode PI and the grid gi in the predictor K; will be greater than the difference between the notacialosis between the cathode of the RE and the grid g-i in the amplifier U2. Therefore, the maximum current will pass through the circuit Di, PI, Ai, UI, DI, and the minimum current and the circuit along the circuit, D2, P, A-j, tJ-i, D., and the generator will be fully excited. During a short circuit, the filament current of the kenotron filaments increases, the temperature of the filaments quickly rises and the current in the anode circuits rapidly grows, accordingly, the voltage on the resistors pressure i decreases, and on the clamps of the resistance RZ rises. With "adennia, the voltage at the terminals to which the cathode / Ci is connected and the net decreases the current in the field winding Ui, which increases the voltage at the terminals of resistance -R. causes an increase in the current through the winding Oz. The total net excitation thus decreases, passes through zero and takes a negative value. Thus, the inducers of the magnitude are magnetised and re-magnetized. With good adjustment by the resistive heaters, as well as the resistances of RI and 2, this negative excitation value can be obtained that the residual magnetism of the exciter will be destroyed to zero. If the short wiring is brief and stops before the disconnecting switch or the carnival shuts off, then when the strand is discontinued, the current through the kenotrons decreases, and the alternator excitation quickly takes on the same value. The author notes that the recapture of kenotrons is not very long (less than a second) and therefore will not respond on the term of service kx.

The subject matter of the invention.

Claims (2)

one-. A device to protect the alternator from short-circuiting by demagnetization and reversal of its inductors with the help of a kenotron when the load current rises above a set limit, characterized in that the kenotron K, which is fed by a circuit from the alternator of the current transformer T, is connected to the circuit excitation of the alternator in parallel with the magnetizing winding and inductors and successively with the weaker demagnetizing winding Ui of the inductors, with the aim of increasing the current in the alternator power circuit and the increase in the cathode filament of the kenotron K, the current in the winding Ui decreased, and in the winding Uz increased (Fig. 1). 2. Modification of the device according to claim 1, characterized by the use of two mercury HOHHosx amplifiers Fj and whose anode circuits are included in the field windings, no, f / i and, respectively, U, and the grid circuits are connected to resistances R and, respectively, from which resistance R is connected in parallel, and resistance / 2-series with phase kenotrons / Cb Ki. Ki, with the aim to increase the current in the alternator power circuit and increase the cathode cathode voltage, the voltage on the resistance and current in the winding "e t / i decreases, and the voltage on the resistance R% and current in the winding Ui, uzdelyvalysy (Fig. 2). e FIG.