SU765931A1 - Spark-proof power supply source - Google Patents

Description

one

The invention relates to the equipment of mine geophysics and automation and communication devices, working in the mines, hazardous by gas or dust.

Intrinsically safe power sources are known, containing a battery, a node for limiting overcurrent and short circuit made on the basis of semiconductor elements 1.

The disadvantages of these power supplies are the complexity and low reliability.

The closest in technical drying and the achieved result is an intrinsically safe power source containing a battery, an overload and short circuit current limiting unit, made on the basis of a thyristor with a resistor in the control circuit, and a transistor switch connected in series with the load and the thyristor 2 .

This device is dry, and the reliability of the recovery and protection properties of the discharge current limiting circuit of the battery at the time of the thyristor node limiting the power and restoring the normal mode is insufficient.

operation of the source after the elimination of an emergency situation in the load due to the variation of the parameters of semiconductor devices, in particular leakage currents.

The purpose of the invention is to automatically connect the power source to the load after the emergency mode is eliminated, as well as to increase the reliability of switching.

This goal is achieved by the fact that the intrinsically safe power supply is equipped with an additional transistor switch, diode, 10 pulse driver based on delay elements and a relay, the diode being connected in series with the thyristor, in parallel with which an additional transistor switch is connected, the diode connected to the pulse driver, the output of which is connected to the winding of the relay, the contacts of which are included in the control circuit of transistor switches.

Claims (2)

The drawing is a schematic diagram of an intrinsically safe power source. 20 The source includes a battery 1, pins 2 included in the control circuit of an input transistor 3 of the delay node, which also includes a transistor 4, a resistor 5, a capacitor 6, resistors 7 and 8, a capacitor 9, a resistor 10, an output transistor 11 of the node delay, winding, relay 12, turned on at its input, transistor switch 13 connected in series to the load circuit, transistor switch 14, current-measuring resistor 15 connected to the thyristor control circuit 16 connected in series with the diode 17. The device works as follows their way. The power supply is turned on by closing the contacts 2. At the same time, the base of the transistor 11 through the current amplifier on the transistor 3 receives an unlocking current, which causes the relay 12 to operate. The latter, with its contacts, ensures the opening of the serial switch and the locking of the parallel key. The open serial key transfers the electrical power of the battery to the load. The voltage drop across the current-measuring resistor 15 is not enough to open the thyristor 16. Consequently, the voltage on the diode 17 is absent and the transistor 4 is locked. In emergency mode, the load, which is an increase in current or short circuit, the voltage drop across the current-measuring resistor 15 unlocks the thyristor 16, bypassing the load. The voltage drop across the semiconductor diode causes the saturation of the transistor 4 and thus the locking of the transistor 11. After the short-circuit power limiting thyristor node triggers, the voltage between points A and B is not enough to hold the relay, which releases the serial key and connects the parallel input circuit key to the current amplifier, performed on the transistor 3. Locking the serial key causes a decrease in current, short circuit and an increase in voltage between points A, B and, therefore, increases the saturation of parallels. key. Since the voltage drop on the saturated parallel switch is less than the voltage drop on the conductive circuit 16, 17, the switch switches off the thyristor 16, after which the release state of the relay 12 is maintained for a delay time determined by the elements of the delay node 5, 6, 7 , and 8, 9, 10. At the end of the delay time, the transistor 4 is closed and the transistor AND is opened, causing the relay 12 to trip. If the emergency load condition is eliminated by this time, the source provides further normal power to the load. Otherwise, the thyristor reopens and the source enters generation mode. By selecting the delay time, the average discharge current of the battery 1 is reduced in emergency mode. When eliminating the emergency condition of the load, the normal operation of the source is restored. Claims of the Invention An intrinsically safe power source comprising a battery, an overload and short circuit current limiting unit, made on a thyristor with a resistor in the control circuit, and a transistor switch connected in series with the load and the thyristor , characterized in that, in order to automatically connect the power source to the load after the emergency mode, as well as increase reliability and switching, it is equipped with an Additional transistor to the 7th diode, a diode, a pulse shaper based on delay elements and a relay, the diode connected in series with the thyristor, in parallel with which an additional transistor switch is connected, the diode is connected to the input of the pulse shaper, the output of which is connected to the relay coil, contacts which are included in the control circuit of transistor switches. Sources of information taken into account during the examination 1. USSR author's certificate No. 412601, cl. H 02 H 7/06, 1972. 2. Mountain machines and automation, 1972, vol. 8, s. 39-40.