SU98459A1 - Device for controlling the speed of a short-circuited asynchronous electric motor and method of its operation - Google Patents

Description

ycxpoircTBo is designed to regulate the rotational speed of a three-phase short-teEclosed asynchronous motor by changing the frequency of the imitation bgo direct current ..

To change the frequency of the voltage supplying the motor, we used the property of an asynchronous generator, the rotor of the rotor rotates at a constant speed from the prime mover, to change the frequency of the removed one; 1nap) marriages in charge of my1; It is taken from its rotor chain.

In the known electric systems of the same name, the frequency change is achieved using a collector generator, which is excited by a synchronous generator, which rotates at a variable speed from an additional DC motor.

The described device allows the change of the mains frequency to power an induction motor with standard machines.

As can be seen from the diagram, the device consists of an asynchronous generator (1). driven at a constant speed — from the prime mover (2), a synchronous exciter (3), with the shaft of which the direct current machine (4) is fixed, three groups of three-phase solid rectifiers (5, G and 7) and an additional driver, in which the usual asynchronous squirrel-cage motor is used; cell (shown in the diagram).

Forward: from the stator winding of the asynchronous generator (1) is applied to the terminals of the squirrel cage asynchronous actuator. A synchronous exciter is connected in parallel with the asynchronous generator (3). The armature of the machine (4) of direct current is fed by a load taken off by i; a rotor of an asy.chroyny generator, which is raised by a three-phase solid (selenium) rectifier (5).

The winding of the excited synchronous exciter (3) is powered by two three-phase hard rectifiers (6 l 7), connected to the side of the direct current according to. From the side of the three-phase current, the one-off of the rectifiers is connected to the stator winding of the asychronous generator (1), and the other, by the rotor ring of this more generator. With this switching on of the rectifier, the constant strut applied to the winding of the driving day will not be affected by the change in the p-p11 to the rotor and stator circuits.

The change in the power taken out of the rotor circuit, and consequently, at the frequency of the voltage supplying the executive motor, is carried out by changing the excitation of the DC mangans. The winding of the latter is the last one supplied to the source of a stable nap1) Ya5eni, which, as OHJCD is indicated above, is the power supply that feeds the winding of the exciter sphronnoto of the exciter. At the excitation current of the mangina DC equal to zero, the output of the rectifier, and hence the rotor rings of the asynchronous generator, will be closed to the machine of the stand-by current. This is equivalent to a short; h; 1 connection in the rotor circuit. The stator current frequency of the asynchronous generator will be at its maximum.

If a direct current machine is excited, then due to the appearance of the electromotive force of the core, the current in the poTfjpa attachment of the asn – nhrn gbNprato will decrease, t, and, consequently, the capacity of the power, tyaraema depn r (| will decrease the frequency of the stator circuit asnnlf ONIOg generator a.

In order to increase the stability of the entire device under strong load jolts, it is envisaged that the stator windings of the asynchronous generator and the synchronous exciter are jointly turned into a series triangle using the contacts (8): contact-pa.

Subject invention

Claims (3)

1. A device for regulating the speed of a short-circuited asynchronous electric motor by changing the frequency of the powered ny Kenn . (stator ayinh1) one-dimensional generator, and a phased phase rotor, rotated by the prime mover at a constant speed, containing a synchronous exciter connected in parallel to the generator, so that, with the aim 1: the user The device of serial electric machines, with the shaft of the synchronous exciter, is rigidly connected to a electric DC machine, in which the measles is fed through a three-phase rectifier from the rings a (; the alternator, and a current regulator is connected to the excitation circuit. 2. The device according to claim 1, distinguishes U1, e e with that. that, in order to obtain a constant voltage supply by the excitation circuit of the machine of the carcass current and the synchronous exciter, two solid three-phase rectifiers were used, one of the K-lines from the side of the H) south current was connected i; the stator of the asynchronous generator, and the other to the rotor count (, q, a5: the latter. 3. The method of operating the device by ip. 1 and 2, characterized in that, for the purpose of increasing the stability of the installation, the windings of the asynchronous generator and the synchronous 013 wake-up connected to the star during power operation, switch without 1) triangles, made up of successively included windings.