SU1261039A1 - Device for overload protection of d.c. source - Google Patents

Abstract

The invention relates to the field of protection of sources of direct current from overload and can be used to protect the electrical equipment of aircraft and their aerodrome mobile electrical installations from the protected ucmatJHUKa. The aim of the invention is to expand the scope and increase reliability. The goal is achieved by introducing into the device a key stage 17, a potentiometer 15 and amplitude converters 4 and 16. When the amplitude converters 4 and 16 are supplied to the input, having a variable component of any form, a constant component is output at their output proportional to the average value stress at their entrance. The device can be used to protect DC sources of different power, regardless of the quality of the electricity of the latter (the shape and size of the pulsations). 1 hp f-ly, 1 ill. c & To consumer

Description

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The invention relates to the field of protection of sources of direct current from overload and can be used to protect electrical equipment of aircraft (A / C) and airfield mobile electrical installations serving them.

The aim of the invention is to expand the scope and increase reliability.

The drawing shows a diagram of the device.

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The device consists of a current sensor 1, the first output of which is connected to the positive terminal 3 of the power source through the disconnecting contact 2, the second terminal of the current sensor is connected to the positive terminal of the power source directly, the adjustable current sensor terminal is connected to the first input (First amplitude converter 4, The second input of the first amplitude converter 4 is connected via a disconnecting diode 5 and a load resistor 1 | The stator 6 is connected to the negative terminal of the power supply; the output of the first amplitude converter is Brazovatel 4 is connected to the first input of the threshold amplifier 7, made for example on a transistor, the code of which is connected to the first stage of the master circuit time, consisting of a charging resistor 8 and a storage capacitor 9, the second time terminal of the master circuit is connected to the negative source terminal power supply through the ballast resistor 10 and the second diode 11, to the positive terminal of the power source through the capacitor 12, to the second input of the final amplifier 13, made, for example, on one input transistor and a tritor twine The first input of the specified amplifier is connected to the connection point of the charging resistor 8 and the storage capacitor 9, the output is connected to the input of relay 14, the terminals of potentiometer 15 are connected to the output terminals of the protected source, the control output of potentiometer 15 is connected to the first input of the second amplitude converter 16, the output of which is connected with the first input of a key stage made, for example, on a transistor and a zener diode, the output is a key 10

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The first stage 17 is connected to the connection point of the isolating diode 3 and the load resistor 6, and the second input of the first amplitude converter 5, the second output of the current sensor 1, the second input of the threshold amplifier 7, the second input of the second amplitude converter 16, the second input of the key stage 17 and the relay output 14 are connected at one point, which is connected to the positive terminal of the power supply.

The device is set to operate at the maximum allowable current in the power circuit using a slider on the variable resistor of the current sensor 1 and at the minimum allowable voltage at the terminals of the protected source using a potentiometer 15.

The device works as follows.

When the load on the electrical unit does not exceed the allowable (peak when the aircraft engine starts up 25 bodies), the signal removed from current sensor 1 is not sufficient to open the threshold amplifier 7, and the voltage drop at the terminals of the protected source does not reach the minimum level. In this case, the voltage taken from the potentiometer 15 flows through the amplitude converter 16 to the input of the key stage 17 and opens it. The voltage at the output of the key stage 17 is minimal (about 0.2 V), and the decoupling diode 5 (silicon) does not conduct, since its cut-off voltage has a value of about 0.6 V. In this case, the input of the threshold amplifier 7, the voltage from the protected source does not fall, the whole device is in standby mode.

If the load on the electrical unit exceeds the allowable, then in the case of the presence of a power reserve of the electrical unit, the signal removed from sensor 1

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current will be sufficient to open the threshold amplifier 7. When

the voltage on the storage capacitor 9 reaches the amount of output of the terminal amplifier 13, the relay 14 is turned on, contacts 2 of which are connected to the power circuit. In case of insufficient power of the electrical unit during an overload, the signal removed from the current sensor 1 is insufficient to open the threshold force 3

bodies 7 due to a decrease in the speed of the drive motor and the voltage drop of the protected source to the minimum level. At the same time, the voltage at the input of the key stage 17 decreases, the latter is closed, and the voltage of the protected source through the load resistor 6 and the dissipation diode 5 enters input of threshold amplifier 7 and open it. The process then proceeds as described.

The essence of amplitude transducer operation is as follows.

When the voltage input to the amplitude converter does not have a variable component, it passes through it without conversion. If there is a variable component, then regardless of its form, a constant component is allocated at the output capacitor of the amplitude transducer proportional to the average value of the voltage at its input. This is achieved by the fact that, in contrast to the known pre-amplifier amplitude converter, there are independent charge and discharge circuits of the output capacitor, and the resistance values of the resistors in these circuits are chosen so as to ensure the independence of the constant voltage on the output capacitor from the ripple at a constant the value of the constant component at the output of the converter.

Capacitor 12 smoothes the voltage ripple, and in case of overload, when the voltage of the protected source decreases sharply, it acts as an autonomous power source.

The invention allows for the effective protection of direct current sources against overload, as well as to ensure the safety of the electrical equipment of the aircraft being serviced.

The proposed device can be used to protect direct current sources of different power irrespective of the quality of electricity of the latter (the shape and size of the pulsations).

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Claims (2)

1. Device dt to protect the DC source from overload, containing a current sensor, a threshold amplifier and a driver time circuit consisting of a series-connected charging resistor and a storage capacitor, to the junction of which the first input of the final amplifier is connected, A relay input is connected to the output of the specified amplifier, which is related to the fact that, in order to expand the scope of application 5 and increase reliability, a key stage, a potentiometer and two amplitude converters, This first vgood The current sensor is connected via a disconnecting contact of the relay to the positive terminal of the load, which regulates the output of the current sensor to the first input of the first amplitude converter, the output of the first amplitude converter of 25 bodies through the series connected dissociating diode and the load resistor to the minus terminal of the protected DC source and to the first input of the threshold 30 amplifier, the output of the key stage, the first input of which is connected to the connection point of the coupling diode and the load resistor The output of the second amplitude of the 5th transducer, the first input of the second amplitude transducer is connected to an adjustable potentiometer terminal, the other two potentiometer inputs are connected to the output 0 terminals of the protected source, the output of the threshold amplifier is connected to the output resistor, which is the first output of the reference circuit, The second pin of the time of the master 5 circuit, which is the pin of the charging capacitor, is connected to the second input of the final amplifier directly and to the negative terminal of the protected source 0 nickname through a ballast resistor and a second diode, and the second the output of the current sensor, the second input of the first amplitude converter, the second input of the threshold amplifier, the second input of the second amplitude converter, 5 bodies, the second input of the key stage and the relay output are connected to one point connected to the positive terminal of the protected DC source. 5 1261039- " 2. The device according to p. 1, about tl and -diode, the second output of the third is resolved with the fact that each am-torus and the first terminal of the capacitor The amplitude converter is designed to output the amplitude of the third and fourth resistors, the driver, to the junction point of the third and fourth diodes and terminal 5 of the third resistor and sensor, with the first two diodes connected to the first output The third resistor is connected to the anodromeple resistor, and the second diode, whose cathode is the fourth resistor and connects with the first input of the amplitude pre-capacitor, is connected to the common converter, parallel to the third resistor, which is the second diode of the fourth diode, the house of the amplitude converter. cathode quarter Compiled by K. Shilan, Editor L. Veselovska Tehred M. Khodanich Proofreader M. Sharoshi Order 5240/54 Edition 612 Subscription VNIIPI USSR State Committee for inventions and discoveries 113935, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Design, 4,