SU1334256A1 - Device for protecting three-phase load - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to protection and control devices for three-phase consumers. The purpose of the invention is to increase the reliability of the device due to the fact that the resistor 16 of the thyristor control circuit 6 is connected to a start button 15 connected to a two-phase switch 17 connected between the input automat 1 and the power contacts of the contactors 2, 3. One end of the current limiting resistor 14 connected to the start button 15 and to the resistor 16 of the thyristor control circuit 6, and the other to the stop button 13 and to the cathode of the thyristor 6, the third resistor 7 is included in the anode circuit. 1 Il. W 00 with 4 SP 0

Description

The invention relates to electrical engineering, in particular, to devices for the protection and control of phase Phase consumers.

The purpose of the invention is to increase the reliability of the device.

The drawing schematically shows the proposed device.

The device for protection of a three-phase load contains an input automaton 1 of a three-phase power supply, connected between the power source and power contacts 2 and 3 of the respective contactors, a three-phase rectifier 4, the anodes of which are connected to the three-phase voltage source between the power contacts 2 and 3 of the contactors and the load 5, the thyristor 6 whose anode

connected to the current-limiting rezi-20 closes and de-energizes the coil

9 or 8 contactors that open contacts 2 or 3 and disconnect the load 5. Therefore, the entire circuit remains in the disconnected and de-energized state of 25 research institutes. The contactors 10 and 11 of the contactors completely exclude the possibility of the simultaneous activation of the coils 8 and 9 (for example, when one of them sticks), which often leads to a short circuit on the load side 5 and failure of the power contacts 2 and 3.

7, connected to the three-phase rectifier 4, coils 8 and 9 of contactors connected via auxiliary contacts 10 and 11 by means of a key 12 to a stop button 13 connected to the cathode of thyristor 6 and a current limiting resistor 14, the other end of which is connected to the starting button 15 and with a resistor 16 connected to the control electrode of the thyristor 6. The two-phase rectifier anodes 17 are connected to the source between the input circuit breaker 1 and the power contacts 2 and 3 of the contactors, and the cathodes are connected to the start button 15.

The magnitude of the resistor 16 is selected based on the reliable opening of the thyristor 6, and the magnitude of the resistors 7 and

14 is based on current limiting and reliable triggering and holding of the contactors both by pressing button 15 and by self-feeding coils 8 and 9.

Device for the protection of three-phase load works as follows.

The input circuit breaker 1 is turned on, the three-phase voltage is applied to the upper terminals of the power contacts 2 and 3 and to the anodes of the top 17, Press the button

whereby the rectifier 17, the button 15, the resistors 14 and 16, the button 13 Stop and the contacts of the switch 12 turn on the coils through the diodes 17

9 or 8. Coils 9 or 8, having turned on, pull in the cores of the contactors (not shown), which close the power contacts 2 or 3 and turn on the load 5, start the three-phase rectifier 4. The current from the rectifier 17 through the closed button 15, resistor 16, thyristor control electrode 6, its cathode, button 13, key 12, pins 10 or 11 contactors, coil 9 or 8, phase N opens thyristor 6. Thyristor 6 feeds coil 9 or 8 on the strand 4 rectifier 4, resistor 7, thyristor 6, button 13, key

12, pins 10 or 11, coil 9

or 8, phase N. As a result, the core of the contactor remains drawn into the coil 9 or 8 and the load 5 remains in working condition even after the button 15 is released and its contact is opened.

In case of loss of voltage at any of the supply phases at load 5, the current of the thyristor 6, zero crossing.

0

9 or 8 contactors that open contacts 2 or 3 and disconnect the load 5. Therefore, the entire circuit remains in the disconnected and de-energized state - 5 research institutes. The contacts 10 and 11 of the contactors absolutely exclude the possibility of simultaneously turning on the coils 8 and 9 (for example, sticking one of them), which often leads to a short circuit on the load side 5 and failure of the power contacts 2 and 3.

When troubleshooting, the device is turned on by installing the key 12 and in one direction or another (closing its upper or lower contacts) and pressing the start button 15. In the future, the device operates as indicated. Thus, this device provides reliable protection against non-full-phase operation of both reverse and non-reverse loads, and the thyristor directly controls the coils of the contactors, as the number of switching contact elements decreases and the electromagnetic relays are reduced.

five

Claims (1)

Invention Formula A device for protection of a three-phase load containing an expander, which has terminals for connection between the power source and the power contacts of the contactors, connected in series with the Start button, in series with which the resistor of the control circuit is connected, an anchor coder This is connected to another three-phase power supply wire, The rectifier has terminals for a sub-current limiting resistor and a third The key to the source of the three-phase nap-resistor, exceptively voltage between power contacts, which, in order to increase reliably the contactors and the load, and the anode of the capacitance, the current-limiting resistor includes the stop is connected to the Stop button, by clicking the Start and Stop buttons, Consequently, with which they are connected to and connected to the thyristor cathode, the anode The carcasses of contactors, the other terminals of which are connected to the rectifier of the four, have terminals for connection to the third resistor.