SU69287A1 - Torsometer - Google Patents

Description

. For measuring power on the shafts of propellers, rolling mills, machine tools and engines, torometers are now widely used, based on measuring the angle of twist of the shaft, which is proportional to the torque transmitted by the shafts.

One of the types of torque meters used in modern installations is phase. The principle of operation of this torsometer is as follows.

Two serrated rotor discs L and B are mounted on the shaft (Fig. 1). A stator having an excitation winding (W and Wj) and a working winding Wpi or Wp ,, laid in its slots are mounted near each disk.

Each rotor and stator forms an alternator, in which, when the rotor rotates, the magnetic flux coupled to the working winding changes, inducing in this winding an electromotive force depending on the speed of rotation of the rotor. Each tooth of the rotor corresponds to one period of change e. d. the stator.

nineteen

Let: Rc is the angular velocity of rotation of the rotor, and the number of turns of the working stator winding D is the diameter of the rotor, BI ... e, are the components of induction in the stator (first and v harmonics), p is the number of rotor teeth, fi and I , - winding coefficients for the 1st and th harmonics.

The electromotive forces of the windings of the first and second stator for the twist angle of the shaft a are:

ei DIWO, Bill sin p (oO + - .. +

+ B & invp (ioi)} e (Bill sinp (Q + a -b ..., .mvp (+ a)} Denote the product: En,

. , E, r. Then:

ei mjsinpfi t - .., + Em, sinvpQ

2 m, sin / 7 (+ a) 4 -... +

-f m sinip (o / - | -a).

291

If the working windings are turned towards each other through a magnetoelectric voltmeter (with a solid rectifier) with high resistance, the stators will be in idle mode, and the low current through the device will be determined by the average value of the electromotive force at its terminals for the half period:

Jl

2 Emed / (1 -

o -1-., sin + ... +

:: - jL sin

Because:

fi

f, And,

then:

  F: in2 p. Vf Cmi Sin-Kit-vi,

--Medged where P is the power transmitted by the shaft, M is the momeite twisting the shaft. It is known that P - MQ, M ka; pa sin pa if.

Therefore, in this form, a device for measuring power cannot be used.

On the other hand, the use of a magneto-electric device with a rectifier is extremely beneficial, since it makes it possible to avoid measurement errors resulting from the variable value of the voltage drop in the stator windings due to their heating or changing the speed of rotation of the shaft.

In order to ensure the use of a magneto-electric voltmeter with rectifiers, it is proposed, in accordance with the present invention, to equip one of the generators with a compensation winding located on the additional stator, and place all three stators relative to each other at angles that ensure a direct proportionality between the average value of e. d. in the circuit of the measuring device and the angle of twist of the shaft.

29Y

FIG. 1, an additional stator with an excitation winding W and a compensation winding Wg is provided with a left-hand generator. The number of turns of the winding Wg differs from the number of turns of the main windings Wp.

All three of the stator are offset at some angle relative to each other.

The windings are turned on as follows (fig. 2): both the winding Wpi and the first generator are in agreement with each other (successively with each other) and opposite to the winding lFp2 of the second generator. The choice of the angle of the stators and the number; 1a of the turns of the additional winding Wg is based on the following conditions:

a) in the absence of a torque on the shaft, the sum of the electromotive forces fi of the main (working) winding of the first generator. E - the additional winding of the first generator to E - the winding of the second generator must be zero for any instant (Fig. 4);

b) the average value of the sum of electromotive forces over a half-period for power should be proportional to this power. These conditions may, for example, be satisfied if:

1) to wind the additional winding Wg of the first generator with a number. turns 1/2 times the number of turns of the main working winding Wp of the first generator (the same effect can be achieved by increasing the ampeed turns of the excitation winding of the additional stator or by a corresponding decrease in its air gap);

2) position the stators with respect to each other with the following shift in electrical degrees: the additional stator with respect to the main stator is with a shift3

gom, equal to + -j-:, and the stator of the second generator relative to the main stator of the first for the

+ -y, including the two windings of the first

generator according to each other and to meet the winding of the second generator (Fig. 3).