SU754311A1 - Rotational speed-to-pulse train converter - Google Patents

Description

The invention relates to measuring equipment, in particular to converters of rotational speed in a sequence of pulses, and can be used in information-measuring systems to control the frequency of rotation of engines.

Known frequency converters in a sequence of pulses, containing a speed sensor (tachogenerator) and a frequency converter in a sequence of pulses are known. In these converters, the sinusoidal voltage of the speed sensor is rectified, formed into rectangular pulses and fed to the input frequency converter. Moreover, due to the low frequency-voltage value generated by the sensor, the frequency is multiplied by an integer.

It is also known a device which comprises a three-phase generator voltage, three rectifier diodes ⁴ so, the anodes of which are interconnected, and amplifier-driver, It is

the device is taken as a prototype [2 ^ ,,

However, this technical solution has the following disadvantages::

2

- the scheme is relatively complex; The rectifier circuit is made on nine-diodes, three resistors and the element "And", which in turn

5 can be implemented at least on three diodes and requires an additional source of stabilized power;

- additional measures are needed to decouple the input and output circuits of the converter (also due to the additional power source), which is necessary to ensure noise immunity (from longitudinal interference) when using converters in information systems where there are other means; In addition, the sensitivity of the circuit is relatively low, and therefore the conversion error is large, especially at low speeds of powerful diesel engines and turbines, which have variable torques, resulting in modulation of the output voltage frequency in amplitude and frequency.

Modulated signals become smoother after rectification

with the level of the main signal that

754311

leads to the appearance of a parasitic pulse between the main information signals, or vice versa - the loss of individual information pulses.

The aim of the invention is to simplify the scheme and increase noise immunity.

This goal is achieved by the fact that three first resistors, three second resistors, a third resistor, three transistors, a capacitor and a transformer are inserted in the device, the generator phases being connected to the cathodes of the corresponding diodes through transistors, whose bases are connected to adjacent phases through the first resistors, the connection point The second resistors, which are connected to the generator phases, are connected to the output side of the transformer primary winding, and through the third resistor to the common point of the diodes, which is connected via a capacitor to a different output terminal transformer winding, the secondary winding of which is connected to the amplifier-driver.

FIG. 1 shows a converter circuit; in fig. 2 - voltage diagrams explaining the operation of the device.

The converter includes a rotational speed sensor 1 - a tachogenerator, the phase outputs of which are interconnected via 2,3,4 resistors, which form a "star".

Transistors 5, 6, 7, 7 are connected to each of these phases, and diodes 8, 9, 10 are connected in series with them, the anodes of which are combined into a common point. The base of the transistors 5,6,7 through ,, respectively, the resistors 11,12,13 are connected to the adjacent phase. The common point of the diodes is 8.9,

10 through a resistor 14 is connected with the midpoint of the "star" formed by the resistors 2,3,4, and through a capacitor 15 with one of the terminals of the primary winding of the transformer 16, the other terminal of which is also 'connected. with another chute "stars".

The secondary winding of the transformer 16 is connected to the amplifier-driver 17.

The operation of the transducer is as follows.

The three-phase sinusoidal voltage from sensor 1 is supplied to transistors 5,6,7, which operate

in the key mode, as a result * the signal goes to the transformer 16 only in the phase in which the base of the transistors 5,6,7 is at a positive potential relative to the collector (figure 2). Diodes 8.9,10

⁵ provide a three-phase rectification and at the same time exclude the passage of equalizing currents between the two phases, the resistor 14 ensures the closure of the electrical circuit at a constant component voltage. Resistors 2,3,4 create an artificial zero for three-phase voltage. Resistors 11,12,13 limit the base current of the transistors. The informational signal (variable component) is extracted through the coupling capacitor 15, the decoupling transformer 16, and is formed by the amplifier-driver 17.

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Claims (1)

Claim A frequency converter into a pulse train containing a three-phase generator, three rectifier diodes, the anodes of which are interconnected, and an amplifier-shaper, characterized in that, in order to simplify the circuit and increase the noise tolerance, the first three resistors, three second resistors, the third a resistor, three transistors, a capacitor and a transformer, and the generator phases are connected to the cathodes of the respective diodes through transistors, the bases of which are connected to adjacent phases through the first resistors, The second resistors are connected to the generator phases, and their connection point is connected to the primary output of the transformer, and via the third resistor to the common point of the diodes, which is connected via a capacitor to another output of the transformer primary, the secondary winding of which is connected to the amplifier-shaper .