SU1555759A1 - Automatic switch for protection of load from connection to ac power supply source with intolerable rated voltage - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to simplify the switch. When the load 1 is connected via a switch to an AC power source 2 with a rated voltage of 127 V, a current flows through the relay coil 8 and positive half cycles. The relay is triggered, and the voltage through the closing group of contact 9 of the relay is applied to output terminal 6 and the corresponding output of load 1. The voltage drop across the coil of relay 8 and the threshold element dynistor 12 does not reach the dynistor switching voltage. The latter is in the closed state, with no shunting effect on the relay coil. When the switch is connected to an alternating current source with a rated voltage of 220 V, a threshold element 12 is opened, and the relay coil is shunted. The latter remains in the initial state, and the voltage through the disconnecting group of contact 9 is fed to the output terminal 5 and the corresponding output of load 1. 3 sludge.

Description

FIG. one

The invention relates to electrical engineering and is intended for use in electrical apparatus to protect against connection to an AC power source with an unacceptable voltage.

The purpose of the invention is to simplify the switch.

FIG. 1 shows the electrical circuit of the switch} in FIG. 2 and 3 are graphs that show his work.

An automatic switch to protect the load 1 from being connected to an AC power source 2 with an unacceptable rated voltage contains the first 3 and second 4 input terminals for connecting to the power source 2, the first 5, the second 6 and the third common 7 output terminals for connecting to the load terminals 1, an electromagnetic relay 8 with a winding and a switching contact 9, a current-limiting element 10, made in the form of a capacitor or a throttle, a diode 11 and a threshold element 12. The first input terminal 3 switches the 9 th relay contact 8 is connected to the first output terminal 5, and by closing the switching contact group - a second output terminal 6. The second input terminal 4 is directly connected to a third common output terminal 7.

The threshold element 12 is made in the form of a dynistor, and between the first 3 and second 4 input pins there is a chain of series-connected current-limiting element 10 and a relay coil 8, while the coil of relay 8 is shunted by a chain of counter-parallel-connected diode 11 and a threshold element of the dynistor 12. Load 1 switch can serve as a welding transformer with a primary winding, designed for power supply of 127 and 220 V.

The switch works as follows.

When a load 1 is connected via a switch to an alternating current source 2 with a rated voltage of 127 V, a positive current flows through the relay coil 8 into positive half-periods, and the network voltage is fed to the output terminal 6 and the corresponding

0

five

output load 1. At the same time, the voltage drop U on the winding of the relay 8 and, accordingly, on the threshold element - dynistor 12 (Fig. 2) does not reach the level of the turn-on voltage and on the dynistor, and the latter is in the closed state without having a shunt effect on the winding relay.

When connecting the input terminals 3 and 4 of the switch to the alternating current source with a nominal voltage of 220 V, the voltage Uk on the winding 5 of the relay 8 (Fig. 3) at the time t. reaches the level of the on voltage of the on-switch element of the dynistor 12, and the latter is opened, while shunting the winding of the relay. The effective value of the voltage on the relay coil in this case is lower than the relay operation voltage, the latter does not work, and the network voltage through the opening group of contact 9 of the relay is fed to output terminal 5 and the corresponding load terminal 1.

Claims (1)

Invention Formula Automatic switch to protect the load from connecting to an AC power source with an unacceptable rated voltage, containing the first and second input terminals for connecting to a power source, the first, second and third common output terminals for connecting to the load terminals, an electromagnetic relay with a switching contact, the current limiting element, the diode and the threshold element, the first input terminal through the opening group of the switching contact of the electromagnetic relay is connected to the first output terminal The output, and through the closing group of this switching contact, is connected to the second output terminal, while the second input output is directly connected to the third common output output, and the first output of the current limiting element is connected to the first output of the electromagnetic turnip winding, characterized in that simplify the switch, the threshold element is designed as a dynistor, and the current-limiting element is a capacitor or throttle, between the first and second inputs five 0 five 0 five 51555759 The conclusions include the chain of the post-electromagnetic relay shunted by a current-limiting chain connected in opposite directions to the connecting element and the winding of the electrically operated diode and the threshold element — the magnetic relay; 0 Fie.2 W. Iff ml. fig.Z