SU1246307A2 - Three-phase starting induction resistor - Google Patents

Abstract

The invention relates to the electrical industry. The purpose of the invention is to increase the stiffness of the mechanical characteristics of an asynchronous motor. The resistor consists of three hollow ferromagnetic cylinders 1 of small diameter, on which are put three aluminum cylinders 2, on which, in turn, three ferromagnetic cylinders 3 are attached, on which windings 4 are attached. All cylinders are of equal length and connected to the ends of two ferromagnetic plates 5, forming a single magnetic circuit. There are three more ferromagnetic cylinders 6 of a larger diameter, inside which there are cylinders 3c with windings A. The cylinders 6, in turn, are interconnected by ferromagnetic plates 7, forming a second magnetic circuit. 1 il. i (About to Od So ISJ

Description

The invention relates to the electrical industry, in particular to control gears used for asynchronous motors with a phase-rotor and is an improvement of a three-phase starting induction resistor according to the author. No. 1088095.

The purpose of the invention is to increase the rigidity of the mechanical characteristics of the asynchronous motor in the operating mode.

The drawing shows the proposed induction resistor.

Induction resistor consists of three hollow ferromagnetic cylinders. 1 small diameter, on which three aluminum cylinders 2 are mounted, on which three ferromagnetic cylinders 3 are mounted, the wall thickness of which is equal to the depth of penetration of the electromagnetic field into this ferromagnetic material at the frequency of the current of the stationary rotor of the engine on which windings 4 are located, all cylinders have equal length and are connected at the ends by two ferromagnetic plates 5, forming a single magnetic circuit. There are three more ferromagnetic cylinders 6 of a larger diamerra, inside which there are cylinders 3 with windings 4. The cylinders 6 are interconnected by ferromagnetic plates 7, forming a second magnetic circuit. Between the windings 4 and the cylinders 3 and 6 there is an insulating layer 8 and 9.

The device works as follows.

When the induction motor is started up, an alternating current flows through the winding 4 of the starting induction resistor, the frequency of which decreases with increasing motor speed. With a current frequency of a fixed rotor

Editor N. Bobkova

Compiled by V. M snikova

Tehred V. Kadar Proofreader S. Ekmar

Order 4017/52 Circulation 631. Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow,, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Design, 4.

The depth of penetration of the electromagnetic field into the ferromagnetic cylinder 3 is equal to the thickness of its walls, therefore in the aluminum cylinder 2, which is

the secondary winding does not induce the induction current and the presence of aluminum in the -1l cylinder does not affect the resistance of the induction resistor.

As the engine accelerates, the rotor current frequency decreases and the electromagnetic field starts to penetrate the aluminum cylinder 2, and at low frequencies the ferromagnetic cylinder 1 also emits an emf in the aluminum cylinder.

and the current flows. With increasing induction current in an aluminum cylinder, the total resistance of the three-phase starting induction resistor decreases.

Therefore, in the proposed device, the resistance of the induction resistor changes more dramatically with the frequency of the rotor current of the motor, than in the known construction. This makes it possible to increase the rigidity of the working section of the mechanical characteristic of the drive with unchanged starting current and starting current of the motor torque.

Claims (1)

Invention Formula Three-phase starting induction resistor on the author. St. No. 1088095, about t and ch, in order to increase the rigidity of the mechanical harallism of the induction motor in the operating mode, it additionally has on each rod a hollow ferromagnetic cylinder, a hollow aluminum cylinder, which is placed over the inner cylinder, and a ferromagnetic cylinder - over aluminum.