SU721804A1 - Device for monitoring and control of mechanical vibrator - Google Patents

Description

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The invention relates to the field of testing equipment, in particular, to devices for monitoring and controlling a mechanical vibrator during tests for fatigue, vibration strength, etc.

A device for controlling the operation of a mechanical vibrator is known, comprising its tachogenerator and a rotation speed indicator 1 connected to it via a rectifier.

The disadvantage of this device is the inability to control the number of operation cycles of the vibrator, which limits its use.

A device for controlling and controlling a mechanical vibrator is known, comprising a three-phase tachogenerator connected to the vibrator drive shaft, a rotational speed indicator connected to it via a rectifier, and an overspeed drive control circuit connected to the tachogenerator. When conducting tests with programming the number of loading cycles, such a device is equipped with a control and monitoring circuit for the number of cycles of operation of the vibrator, including

a frequency divider and a pulse counter connected to its outputs and a pulse-counting programmer 2.

However, to ensure the operation of the last circuit, an additional speed sensor, photoelectric or inductive, is introduced into the device, which complicates the device.

The purpose of the invention is to simplify the design of the device.

The goal is achieved in that in the device containing a three-phase tachogenerator connected to the vibrator drive shaft, a rotational speed indicator connected to it via a rectifier, a vibrator drive control circuit and a circuit for controlling and controlling the number of cycles of the vibrator, including a divider the frequencies and the pulse counter and the pulse-counting programmer connected to its outputs, the cycle number monitoring and control circuit is also connected to the tachogenerator, while the indicator the rotational speed is connected to the first and second phases of the tachogenerator, and the vibrator drive control circuit for speeding and the cycle number monitoring and control circuit are connected to the first or second and third phases.

FIG. 1 is a block diagram of the described device, and FIG. 2 - its basic electrical circuit.

The device includes a three-phase tachogenerator 1, mechanically connected to the drive axis of the controlled vibrator 2, a speed indicator 3 connected to phases A and B of the tacho generator 1 via rectifier 4, and connected to phases B and B of the tachogenerator by a speed-exceeding control circuit and monitoring and controlling the number of cycles of operation of the vibrator 2. The control circuit of the drive of the vibrator 2 for speeding contains a threshold element 5 for generating a control signal with unacceptable speed deviations from the setpoint and and additionally bodies 6 for automatic emergency shutoff vibrator 2 signaling and switching its mode of operation.

The control circuit and the number of cycles of operation of the vibrator includes a pulse shaper 7, a frequency divider 8 with a device 9 for setting its initial state and a pulse counter 10 pulses connected to the outputs of the frequency 8 frequency counter 10 and the pulse-counting programmer II, input w vibrator control systems 2 2.

When the emergency protection level needs to be automatically adjusted at the stages of the program being implemented, the threshold element 5 may be associated with the software of the control system 12.

The pulse shaper 7 is made in the form of an asymmetric trigger with an emitter link on transistors 13, 14.

Frequency divider 8 is a four-bit trigger counter with feedback from the third trigger to the first and second, each of the counter bits being a static trigger on transistors 15-22 with automatic bias. The feedback element is the amplifier on the transistor 23. The device 9 is assembled on the transistor 24 and the capacitor 25.

A switch 26 serves to set the division factor of frequency divider 8. The output of the frequency divider is connected to a pulse counter 10 and a pulse-counting programmer 11 via power amplifiers on transistors 27, 28, 29, 30 and relays 31, 32 with contacts 33, 34. Switches 55, 36, 37 serve to set the type of output output. signals; The lamp 38 is designed to signal the turning on of the counter 10.

The threshold element 5 is assembled on the transistor 39; A variable resistor 40 is used as the response level control unit. The executive relay 41 (with contacts 42, 43, 44) of the emergency protection is connected to the collector circuit of transistor 39 via the return 45 button. The lamp 46 serves as an alarm.

As an indicator of 3 speeds, a microammeter is used, equipped with a switch of 47 measuring ranges.

The device works as follows.

When the vibrator 2 is turned on, current pulses with an amplitude depending on the speed of rotation of the vibrator appear at the output of the generator 1. The electrical signals taken from phases A and B of tachogenerator 1 are rectified, and the rectified current, the magnitude of which is proportional to the speed of rotation of the vibrator, is sent to indicator 3.

From phases B and C, the signals from the tachogenerator 1 directly (without rectifying) arrive at the input of the driver 7 pulses. Pulses of constant amplitude appearing at the output of the former at vibrator speeds of 30-50 rpm and higher are directed to frequency divider 8.

When the power is turned on, the transistor 24 J opens for a short time the charging current of the capacitor 25. At the same time, the trigger setup bus is connected to the “–f bus of the power supply.

The output signals of the divider 8 frequency in the form of voltage pulses taken from

 the collector of the transistor 27, or in the form of contact closures 33 of the relay 31 are directed to the pulse programmer 11 and the pulse counter 10. By installing switch 26 to any position (except for the position corresponding to division factor 1), it is possible to obtain additional output signals without frequency division in the form of voltage pulses taken from the collector of transistor 30 and preamplified

0 in the transistor 29, or in the form of contact closure 34 relay 32.

If the speed of the vibrator exceeds the maximum allowable, which corresponds to the setting of the variable resistor 40, then

The j signal at the input of the threshold element 5 on the transistor 39 becomes sufficient to trigger it and turn on the alarm protection and alarm system.

To remove the blocking of the threshold element 5 after eliminating the cause of the protection, it is necessary to briefly press the button 45.

By simultaneously performing such functions as indicating the rotational speed of the vibrator drive, controlling the drive of the vibrator by exceeding the speed, monitoring and controlling the number of cycles of the vibrator when using signals from one common sensor (three-phase tachogenerator), the device for controlling and controlling the mechanical vibrator is greatly simplified. At the same time, the effect on the accuracy of the speed control of the other chains is almost completely excluded.

Claims (2)

1.Litvak V.I. Automation of fatigue testing of full-scale structures. M., “Mechanical Engineering, 1972, p. 146. 2.Litvak V.I. Unification of automated installations for fatigue testing of aircraft structures. “Aviation industry, 1971, No. 2, p. 73-75 (prototype). I