SU472356A1 - Warning device - Google Patents

Description

I

The invention relates to the field of automatic signaling and, in particular, is intended for discrete signaling of minimum frequencies of rotation of the shafts of turbomachines and other production mechanisms that do not have mechanical contact with the meter.

A device for warning signaling is known comprising a sensor and an actuating unit.

However, such a device does not provide stability of settings, operation stability at low (less than 5-7 Hz) frequencies of an electrical signal, has a low return coefficient, a large response and return time, large dimensions and weight when used as signaling devices of serially produced devices with an analog input.

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

This is achieved because a differentiated circuit, a trigger, a voltage divider and time delay elements are introduced into the device. The time delay elements are made on transistors connected in series with a direct connection. The input of the first time delay element is connected via a differential circuit to the output of the sensor, the output is connected to one input of Tri2

directly, and via a voltage divider, to the input of the second time delay element, the output of which is connected to another trigger input. The trigger output is connected to the input of the execution unit.

The basic electrical circuit of the warning device is shown in the drawing.

The output of frequency sensor 1, which produces rectangular pulses with a frequency proportional to the frequency of rotation of the shaft, through a differential circuit 2 is connected to the input of the first element 3 of the time delay, performed on transistors 4-6, of the charging circuit

from the resistor 7 and the capacitor 8, which performs a comparison of the period of positive propagation pulses arriving at its input with a given time determined by the parameters of the charging circuit and the position of the moving contact of the potentiometer 9. and through voltage divide 11, to the input of the second time delay element 12 at transistors 13-15, the charging circuit at resistor 16 and capacitor 17, the output of which is connected to another in a stable trigger 10. The second delay element temporarily returns

0 bistable trigger to its original state

through the time determined by the parameters of the charging circuit of the resistor 16 and the capacitor 17, as well as the position of the movable contact of the potentiometer 9. The output of the trigger 10 is connected to the input of the output actuating unit 18.

When the first element of the delayed positive differential pulses from sensor 1 is applied to the input, transistor 4 starts to switch the charging circuit of capacitor 8. The voltage across the capacitor depends on the time during which transistor 4 is in the closed state. In this case, the closing time of the transistor 4 is determined by the period of the pulses coming from the sensor. If the period of the incoming pulses is so long that the capacitor 8 has time to charge to the switching level of the transistor 5, the latter opens. This opens the transistor 6, which switches the trigger 10 and changes the matching of the voltages on the resistors 19, 20 of the voltage divider 11. The input transistor 13 of the second time delay element connected to the divider 11 is opened, the capacitor 17 is discharged, and the transistors 14 and 15 are closed. Under the action of the trigger 10, the actuating unit 18 is switched and gives a signal that the shaft rotation frequency has decreased.

In such a state, the device can remain as long as desired until the trigger in the initial initial state returns the second delay element. This occurs when the frequency of the pulses increases, i.e., the frequency of rotation of the actuator shaft increases and the period of input

signals, the capacitor 8 does not have time to charge to the switching level of the transistor 5. The transistors 5, 6 and 13 in this case are closed. Capacitor 17 starts charging.

When the capacitor 17 is charged to the switching level of the transistor 14, the latter opens. The transistor 15 also opens and places the trigger 10 in the initial state, and it, in turn, returns to the initial position the executive unit 18, which indicates an increased frequency of rotation of the shaft. The change in the level of operation of the device is carried out using the potentiometer 9.

Subject invention

A warning signal device comprising a sensor and an execution unit, characterized in that, in order to increase the reliability of the device, a differentiating target, a trigger, a voltage divider and time delay elements are inserted in it, the time delay elements being implemented on transistors connected in series with directly connected, the input of the first time delay element is connected via a differentiation circuit to the sensor output, the output of the first time delay element is connected to one input of the trigger EPA itself, and through a voltage divider - to the input of the second delay element whose output is connected to another input of the flip-flop, whose output is connected to an input of the execution unit.

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