SU115421A1 - AC Time Relay - Google Patents

Description

The proposed AC time relay is of the relay type based on the principle of charging a capacitor with rectified alternating current pulses and having an output magnetic amplifier.

The peculiarity of the proposed relay, which extends the range of time settings per relay, is that the capacitor is charged by two adjustable pulses of rectified current of different polarity, so that a larger pulse charges the capacitor, and a smaller one partially discharges it. , elongation process: charge and increase the delay time of the relay.

FIG. 1 shows the electrical circuit diagram of the proposed relay; in fig. 2 - pulse diagram.

With the open control contact K in the primary circuit of the peak transformer and the closed contact / fa in the discharge resistance circuit R of the capacitor Ci, the circuit is ready for action. The capacitor C is completely discharged. (Transformer Tr-2 is powered by a voltage regulator).

The countdown starts from the moment the contact K is opened and the contact K is closed.

When contact K is closed, the primary winding of the peak transformer Tr-1 is supplied with syn 1: an alternating supply voltage, as a result of which in its secondary windings voltage pulses and 1 "having a pointed peak shape are induced (Fig. 2). These pulses serve to momentarily, alternately and periodically open the semiconductor gates Si and B (Fig. 1). U ,, (FIG. 2) is the ignition voltage of the neon lamp L.

When valves B are opened, which occur every time when the voltage on the secondary winding U of the transformer Gr-2 passes through a positive maximum, a current is flowing through the BI valve, charging capacitor Сь

L 115421

When the valves VB occur every time the voltage at the secondary terminals // 2 passes through the negative maximum, the current flowing through the BZ valve discharges the capacitor Ci in FIG. 2 shows positive (charging) pulses and „1 at the beginning of the charge of the capacitor Ci and negative (discharging) pulses - / и2 at the beginning and end of the charge of this capacitor.

Since the voltage at the terminals of the secondary winding I / i of the transformer Tp-2 is greater than the voltage on the terminals of the secondary winding // 2, the charge difference accumulates and the voltage on the capacitor Ci slowly increases.

The voltage across capacitor C causes a decrease in the charging and an increase in the discharge current. They will remain unchanged and equal to their original values (at the beginning of the charge) only if, at variable voltages on the capacitor Ci, the following equality is observed:

(and ,, - and,) + UK - (U, „h LJ, J and„, - и. (1) where; and „, is the maximum voltage on the winding // i of the transformer Tr2;

and ", - the maximum voltage on the winding // a of the transformer

 difference in maximum values of voltages (J, n / 7n, 2 causing inteN | capacitor charge Сnv

and - voltage on the capacitor C

and / - voltage at the output of the magnetic amplifier ICD.

From equality (1) it follows that;

Up 2 and, (2)

To eliminate the effect of the voltage on the capacitor Ci (equal to LJ, g} on the condition of its charge, the circuit of the capacitor C, containing the valve B and the secondary winding 7/1 of the transformer 7p-2, is automatically introduced to a voltage of 2 { Y „see Fig. 2d, which shows positive (charging) pulses at the end of the charge of capacitor C ;.

This voltage is removed from the load resistance R of the differential magnetic amplifier MU 4, the control winding of which is connected in parallel to the terminals of the capacitor C through the filter (resistance RZ and capacitor Cg) in capacitor C The voltage curve V ,, (non-smoothed) of capacitor Ci is shown in FIG. . 2nd. The plots correspond to the moments of charge, the plots 2 ъ 4 are the discharge (pa resistance) and the plots 3 are the discharge of the capacitor GI by negative pulses.

The timing ends when the voltage on the capacitor Ci reaches its maximum value, equal to.

The moment of voltage rise on the capacitor Ci up to a maximum value of 6, is fixed by means of a differential magnetic amplifier MUz (e positive feedback) as follows.

The control / magnetic amplifier MU winding connected through a filter (resistors R, Rz and capacitors C ,, Cz) in parallel to the terminals of the capacitor C arges directly proportional to the voltage at the terminals of the capacitor C. This current creates amnag magnetizing, counteracting the control winds 2, which is set when adjusting the exposure time, by means of an adjustable resistance, connected in parallel with winding 2 in parallel to the clamps of the rectifier; and the charge time of the capacitor Ci predominates. t ampeaters of control winding 2, and the voltage at the output of the magnetic amplifier IVU2 has a negative sign.

There is no current in the winding of the output electromagnetic relay of the RI connected in series with the valve 4, as well as in the winding of the positive feedback.

As soon as the voltage on the capacitor becomes slightly larger than the maximum value Uk, the control winding amnervities will prevail, and the voltage sign at the output of the magnetic amplifier MU will be reversed.

When the voltage sign at the output of the magnetic amplifier MU is changed, the current will pass through the RI relay winding as well as the feedback winding and, due to the strong feedback, will reach the response current of the RI output relay with a very small prevalence of control winds 1.

Having triggered, the RI relay with its normally open RI-1 contact closes the capacitor C to the discharge resistance R (as a result of which the capacitor Ci is discharged) and, by its normally open contact RI-2, switches on the external automation circuit.

If then the control, and the contacts K and Kc are not reset to their original position, then, after the discharge of the capacitor Ci, the relay RI will release its measles, and the time process will repeat again.

The main way of adjusting the time delay is to change the difference between the maximum voltages {/, "- and U", (charging, its and discharging pulses) by changing the number of turns of the secondary winding // 1 of the transformer Tr-2.

To simplify the switching device, the second part of the secondary winding // 1 is divided into sections 1, 2, 3 ... (n-1) and n, each containing K, 2K, ..., (and turns and switched by means of switch P. When swapping the switch plugs into the sockets connected to the terminals of the secondary winding // sections, you can get 2 fixed time delays.

If the adjustable resistance 4 makes several taps, switched by the relay contacts from the external automation circuit, then during one cycle of the relay operation several different time delays can be obtained (these taps from the resistance and the relay contacts are not shown in Fig. 1).

By calculation, the proposed relay allows you to create time delays in the range of 5 seconds. till 20 o'clock

AC time relay based on the principle of charging a capacitor by pulses of rectified alternating current, having a magnetic amplifier at the output, characterized in that, in order to expand the range of time settings on the relay, the capacitor is charged with two adjustable pulses of rectified current different polarity so that a larger pulse charges the capacitor, and a smaller one partially discharges it, lengthening the charging process and increasing the delay time of the relay.

Subject invention

Adjustment Exposure Burden

7

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