SU1567797A1 - Spark-proof power-supply source - Google Patents

Abstract

The invention relates to electrical engineering and can be used in apparatus operating in explosive atmospheres of enterprises of the mining, petrochemical and gas industries. The goal is to increase the intrinsically safe power and reliability. The device contains a primary power source 1 and an inverter, made on transistors 2.3 with control node 4, recovery node 5, isolation transformer (T) 6, current-measuring resistor (P) 7, diode bridge 8, shunt thyristor (PC) 9, pulse T 10, two rectifiers 11, 12 and a resistive divider 13. The secondary winding T 6 is connected in series with P 7 and the load 14. The diagonal leads of the alternating current of the bridge 8 are connected to the load 14. The diagonal of the direct current of the bridge 8 is turned on the ШТ 9. В control circuit PC 9 through the rectifier 12 is turned on winding 15 T 10, the winding 16 of which is connected via rectifier 11 to the input of divider 13. Primary winding 17 T 10 is connected in parallel to P 7. In nominal mode, the output voltage of rectifier 12 is less than the response voltage of PC 9 and the latter is closed. In emergency mode, the PC 9 turns on and shunts the load 14. By appropriately selecting the parameters of the divider 13, a mode is obtained when the PC 9 first operates and then the recovery node 5 is activated. In this case, from the last output to the input of the control unit 4, a signal of a predetermined duration is received, which closes the transistors 2.3 of the inverter. As a result, a reliable restoration of the non-conducting state of PC 9 takes place when the emergency state of load 14 is eliminated and the overload protection trips more quickly. 1 il.

Description

The emergency mode of the PC 9 turns on and shunts the load 14. By appropriate selection of the parameters of the divider 13, the mode is obtained when the PC 9 first operates and then the recovery node 5 is turned on. In this case, from the output of the latter to the input of the control unit 4, a signal of a predetermined duration is received, closing the inverter transistors 2, 3. As a result, a reliable restoration of the non-conducting state of PC 9 takes place when the emergency state of load 14 is eliminated and the overload protection trips more quickly. 1 il.

The invention relates to electrical, engineering and can be used in equipment operating in explosive atmospheres of enterprises of the mining, petrochemical and gas industries.

The aim of the invention is to increase the intrinsically safe power and reliability of operation.

The drawing shows a functional diagram of the device.

The device contains a primary power source 1 and an inverter made on transistors 2.3 with a control node 4, a recovery node 5, an isolation transformer 6, an spark protection node including a current-measuring resistor 7, a diode bridge 8, a shunt thyristor 9, a pulse transformer 10, two rectifiers 11, 12 and a resistive divider 13. The secondary winding of the isolation transformer 6 is connected to a series-connected current-measuring resistor 7 and a load 14. The pins of the diagonal of the alternating current of the diode bridge 8 are connected A load 14 is connected to the diagonal of the direct current of the diode bridge 8 including a thyristor 9, the control circuit of which through the rectifier 12 includes the winding 15 of the pulse transformer 10. The winding 16 of the pulse transformer 10 is connected via the rectifier 11 to the input of the resistive divider 13, the output of which is connected to the input of the recovery node 5, the output connected to the auxiliary input of the control section 4. The primary winding 17 of the transformer 10 is connected in parallel with the current-measuring resistor 7.

The device works as follows.

In the nominal load mode, the voltage at the output of the rectifier 12 is proportional to the voltage drop.

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on a current-measuring resistor 7, the thyristor 9 operates at a lower voltage and is closed. At the same time, the voltage of the output winding of the isolation transformer 6 is applied to the load 14.

In the emergency state of the load, when the current in the load is equal to or greater than the threshold value, the voltage at the output of the rectifier 12 exceeds the response voltage of the thyristor 9, while the voltage at the output of the resistive divider 13 is not sufficient to operate the recovery node 5. The thyristor 9 starts up, the current through the resistor 7, equal to the sum of the currents in the thyristor circuit 9 and in the load 14, increases, the voltage at the output of the rectifier 12 increases, ensuring fast and reliable unlocking of the thyristor 9 and shunting the power source. At the same time, the current through the resistor 7 becomes equal to the short-circuit current of the power source, the voltage at the output of the resistor divider 13 exceeds the response voltage of the recovery node 5. From the output of the restoration node 5, the input of the control section 4 receives a signal of a predetermined duration, as a result of which the inverter transistors 2.3 are closed, the voltage on the output winding of the transformer 6 becomes equal to zero. The duration of the signal from the recovery node 5 should not be less than the recovery time of the thyristor 9. At the end of the signal from the recovery node 5, the control node 4 resumes the supply of control pulses to the bases of transistors 2.3, a voltage appears on the output winding of the transformer 6, and If the fault condition is resolved, the process described above is repeated.

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As the primary power source 1, a battery can be used.

Recovery node 5 is a one-shot forming pulse, the duration of which is selected based on the recovery time of the thyristor 9.

Experimental studies of an intrinsically safe power source have shown that for a power source with an intrinsically safe output having a РЫх ® 8х15 W, using the proposed technical solution allows increasing the intrinsically safe output power up to 18 W (20%)

In addition, the invention provides improved reliability of the power source operation by reliably restoring the non-conducting state of the thyristor while eliminating the emergency state of the load.

Claims (1)

Invention Formula Intrinsically safe power source containing a primary power source, an inverter with a control node, a recovery node, an isolation transformer, the secondary winding of which ten 677976 connected in series with a current-measuring resistor and load, and a shunt thyristor, characterized in that, in order to increase the intrinsically safe power and reliability, it is equipped with a diode bridge, a resistive divider, two rectifiers and a pulse transformer, with the primary winding of the pulse transformer connected - parallel to the current-measuring resistor, and the leads of the secondary windings are connected to the inputs of the first and second rectifiers, the output of the first rectifier is connected to the input of the resistive divide l, the output of which is connected to the input of the recovery node, the output of which is connected to the input of the inverter control unit, the positive output of the second rectifier is connected to the control electrode of the shunt thyristor, and the negative output is connected to the cathode of the shunt thyristor, the diode bridge of the AC diagonal terminals is connected parallel to the load, and the terminals of the diagonal DC are connected to the terminals of the anode and cathode of the shunt 30 thyristor.