SU48702A1 - Device for automatic regulation of an electric motor - Google Patents

Description

It is widely known to use motor relays that are included in the circuit of electric motors and control regulators that control them, for the purpose of automatically controlling these motors depending on the load.

The present proposal relates to similar devices for automatic. Competently adjusting electric motors containing a servomotor (or relay) loaded with an adjusting spring, connected in series to a regulated motor circuit and controlling an adjusting motor rheostat depending on the load of the latter. According to the invention, in the inventive device, a rheostat and a current direction switch are included in the servo motor circuit (or relay); This is done with the goal of carrying out engine performance to any characteristic from different families of falling or increasing characteristics. This circumstance makes the controlled electric motor universal in its characteristics.

In the drawing fpg. 1--3 depict electrical circuits for switching on the proposed device; fng 4-13 are diagrams and curves explaining the essence of the sentence.

In series with an adjustable electric motor D, a servo motor CM is switched on (which can be niyiiTii resistance P) or a relay. This servo motor is used to drive the contact knob 3 of the adjusting resistor 1, 2n of the dnngathol circuit, for example, in the exciter circuit (if the latter is a direct current motor), as shown in the drawing. On the diagrams of the pack; diagrams: W-exciter diplipater winding, PP-not automatic regulator and rheostat, IIP-starting rheostat. And the chains of the SM servomotor are located adjusting rheostat 5 and not showing pi gp; in the drawing switch on current.

In the device of FIG. 2, the SM servomotor is designed according to the wattmeter principle, i.e., it has current rolls and is straight.

To install the lever 3 into the initial position of the subcap, the servo motor system is loaded;) by means of a sprung spring, secured with the other end of the sub-end (Fig. 1, 2) or a movable part of the second such and ;; 3) for the purpose of automatic c) recording the load of changing press IIJ N 4.

For proper operation of the device, it is necessary for motor D to work on the right side of the magnetization curve (Fig. 4), on which there is a proportional ratio between the exciter n-ia amperage and magnetic induction B or, equivalently, between aw and the engine speed n .

It is perfectly obvious that in the devices of FIG. 1 - 3 when the load changes, the blower changes (in the case of a constant mains voltage) the amperage at the value of the motor. This leads to the fact that the balance between the torque of the spring 4 and the servo of the servomotor is broken and the contact lever 3 will take a new position, thereby changing the resistance of the excitation winding circuit, which will automatically change the strength of the excitation current and magnetic flux of the inductors, and thereby engine Thus, through the proposed device, the magnetic flux F becomes a function of the load. You can express the value of the magnetic flux by the following formula:

Ф А. /

where k const.

The value and sign of the coefficient t depend on the resistance of the C / W servo motor and on the direction of the current in it; this resistance is changed by a rheostat 5, and the direction is tOKa-switch (not shown in the drawing).

If the engine of the rheostat 5 put on idle contact; then Ф will cease to be dependent on /, which is obtained at m 0. In this case, motor D will operate according to the shunt characteristic (Fig. 5), and it is possible to adjust the speed by moving the adjustment resistors by hand.

By selecting the corresponding resistance of the rheostat 5, one can obtain / «1; the engine will work on the serial characteristics (Fig. 6).

By changing the resistance of the rheostat 5 from the value of 7 (at) to infinity, one can get all sorts of compound characteristics (Fig. 7); these characteristics are therefore obtained at.

With the resistance of the rheostat 5, a smaller value, new characteristics are obtained, called by the applicant "ultra-series" (Fig. 8); here .

The engine can give enie and characteristics corresponding to m 0 (Fig. 9). Here, with increasing load, engine speed should increase. Since when working on the shunt characteristic: (Fig. 5) the number of revolutions is HCCKO.H.IU. With an increase in load, then to achieve a strictly constant number of revolutions, you can choose the appropriate one. To obtain these characteristics, it is necessary to change the direction of the current in the servomotor circuit by means of a switch not shown in the drawing.

The transition of the engine from one operating characteristic to the other is accomplished exclusively by simply changing the magnitude, resistance of the rheostat 5.

The ability of the engine to operate with enhanced fields F allows one to overcome the very significant moments of resistance M with a pumping increase in energy and even with energy reduction. This circumstance makes it possible to work in the latter case with characteristics that correspond to - 0.

This opportunity can be shown as follows. Suppose we have two engine operating modes:

1) F,. / and MI - torque;

, 2) - / to Mg - the turning moment.

Suppose that

  and Then

.

g / (g

A | / -r ifcJ; 4 iTJ From here

(G (C

F1 F1,

and so

as

. only

On these characteristics (Fig. 10), the overcoming of the increasing moments is resisted by the decreasing current due to the predominant increase in the force field. As a special case of using such a characteristic, the engine can work when the characteristics are almost vertical (Fig. 11).

To accomplish this, it is sufficient to respectively weaken the pressure of the spring 4 and change the resistance of the rheostat 5. To be able to automatically obtain the characteristics - O

it is necessary to apply the second C / I servomotor, which controls the pressing of the spring — and having a separate current branch, similar to the SM servomotor, also with its resistor 6 (Fig. 3),

From the statement of the properties of the engine, regulated by the proposed device, the following follows:

1. The engine receives a working property with different values of the coefficient / s. Different working conditions determine the feasibility of working on the most advantageous characteristics for a given case. So, for example, a different profile of a track and a type of train in an electric locomotive dictates the need to work in different conditions according to different performance characteristics. The proposed device, as has been shown, extremely simply adjusts the engine to work, but any of the above characteristics. In ordinary motor installations, the very possibility of working on various characteristics is completely excluded (constructively).

2. The engine gets the opportunity to work on three new characteristics: a) an ultra-series with / l 1, making it possible to overcome the increased moments of resistance due to the predominant increase in the force field and a relatively weak increase in current, but accompanied by a significant decrease in the number of revolutions. In a number of cases, this characteristic can be very economical and warns the station and the network from current shocks; c) characteristics / l O (increase in speed with increasing

load), which can be practically applied to maintain f f constant number of gears;

c) characteristic - O, on which

the overcoming of increasing momentum takes place with decreasing energy output.

3) Plavgga, wide, losslessly regulating the speed of the rotation over a wide range, the predalist is a great deal of confusion with conventional motor installations, since in the latter case, the achievement of adjustment within these limits leads to the need to apply non-economic techniques or significantly complicate the circuit is an expensive additional device, and the adjustment of the serial engine occurs in steps in steps.

4. The presence of the possibility of operating on a large power field allows one to overcome the enormous moments of resistance with small increases in current or without it at all. By the same way, overcoming of the moments with an insignificant current strength and overcoming of very large moments with a relatively small increase in the current strength is achieved.

5. The simplest recuperation of electric energy is possible: it is produced automatically without any switching with the return of energy to the network (as with conventional shunt engines).

6. It is possible the simplest electric braking without any additional devices; it can produce by moving to reinforced force fields.

7. The ability to. Different conditions for working according to the best characteristics indicate the efficiency of a motor unit equipped with the proposed device.

FIG. 12 and 18 show samples of characteristics (moments and revolutions) that can be obtained from an electric motor equipped with the proposed device.

The subject matter of the invention.

1. A device for automatic regulation of an electric motor.