SU142049A1 - Apparatus for obtaining a speed ratio of two shafts - Google Patents

Description

The known devices used to obtain the ratio of the speeds of the two shafts, made in a closed loop with negative feedback and variable gain, use tachogenerators as speed sensors, and as a divider, either a logometer or electronic potentiometers. Such devices are bulky, have a complex scheme and are not very reliable in operation.

In the proposed device, a tachoheperator with an excitation winding is used as a device with controlled transmission coefficient. This makes it possible to significantly simplify the design of the device and increase the reliability of its operation.

FIG. 1 shows a block diagram of the described device; in fig. 2 - a variant of this scheme.

The device is a closed-type circuit containing tachogenerators 1, 2 serving as multiplying devices. The tachometer / made on a permanent magnet has a constant transmission coefficient, and the tacho generator 2, which serves as a device with a controlled transmission coefficient, is provided with an excitation winding. The scheme is covered by a deep negative feedback and operates as follows.

The input of amplifier 3 is supplied with a difference between current 1, which is proportional to the rotational speed n of the first shaft, not shown in the drawing, and current / 2, proportional to the product of the rotational speed of the second shaft shaft and excitation current / tachogenopropulator 2. excitation of the tachogenerator 2.

At system equilibrium

h C, 4, n, (2)

/, (, (/, - / 2), (3)

Ui Cini; (/ 2 C2 / g "2 or /, C, -L1 (1)

L1 142049-2 where: Ku V-gain amplifier;

t- / i; / t-voltage and current at the output of tachogenerator 1; L / 2, / 2 - voltage ..and, the current at the output of the tachogenerator 2.

--S- - / 1 / ,: - С / «, - С / 4 / г,. (4)

 “Chu - J-4-; AV

With a relatively small gain factor (Ku - LB-20), the left side of equation (4) can be neglected. Then: С / ni-С2 / П2 0 (5), i.e.

/ C / ui L -. (6)

 O2 /

Thus, measuring the current or excitation voltage of the tachogerator 2, an amount proportional to the speed ratio of the tachogenerators /, 2 is obtained. Instrument 4 serves as a recording device.

The described device is used only with significant changes in the speed ratio of the two shafts, and with small changes the scale of the registering device is not fully used, as a result of which the measurement accuracy drops sharply.

In order to expand the possibilities of using the circuit as a device with a controlled gain, a tachogenerator with two windings 5, 6 excitation is used. An excitation current is supplied to the winding 6, the value of which corresponds to the lowest value of the ratio of speeds. The scale of the registering device 4 is used in this case completely, since only the variable part of the excitation current passes through the winding 5.

Equations (2), (4), (5) take the form:

/ o - So "o (

.С, ХС / «, (/.„, + / „, ..);

s, n., - S. / Yao (, 4- / „.,} - o, where

/, „- stabilized current supplied to the winding 6; (&Apos;) (-the varying part of the excitation current supplied to the circumference 5 of the tachogenerator 2.

I - I AI 1 / I С /, p.,

If / „„ - .: (-) (- i- min, then with - (- 4, .. о.) / П-2 I2 -а,

The device can be used in textile production, where it is necessary to determine or adjust the amount of deflection of the speeds of two shafts.

The subject is invented and

A device for obtaining the ratio of the speeds of two shafts, made in a closed loop with negative feedback and variable gain, characterized in that. in order to simplify the circuit, in some cases, as a device with a controlled transmission coefficient, a tachogenerator with a winding in the loop is replaced.

/

P2 l Y

UrU2

 I

FIG. 2