RU80079U1 - ASYNCHRONOUS MOTOR ROTOR - Google Patents

Abstract

The utility model relates to electrical engineering and can be used in electrical engineering for the manufacture of multiphase short-circuited windings of rotors of induction motors. The rotor of an induction motor is claimed, which comprises a magnetic circuit fixed to the shaft in the form of a core with grooves. A short-circuited winding made of cast copper is placed in the grooves. Alloying elements - lead, tin, bismuth, antimony and nickel - are additionally introduced into the copper cast metal of the short-circuited winding. In the metal of such an alloy, the copper content is 98.80-99.95%. The technical result consists in increasing the resource and increasing the operational reliability of the induction motor due to an increase in electric and thermal conductivity, as well as in increasing the density of copper cast metal of short-circuited rotor windings, reducing harmful noise and vibration. 3 points of the formula.

Description

The utility model relates to electrical engineering and can be used in electrical engineering for the manufacture of multiphase squirrel-cage rotor winding of asynchronous motors for heavy duty.

The prior art rotor of an induction motor, the short-circuited winding of which is made of conductive copper rods. The rods are interconnected by short-circuiting rings by soldering or crimping with copper powder, followed by heat treatment, providing sintering of the material of the shorting rings with the winding rods (1).

The disadvantage of such rotors is the presence of gaps between the rods and the walls of the grooves, which cause high resistance to heat transfer from the rods to the core. In addition, the presence of gaps causes significant mechanical stress, as well as vibration of the rods. Vibration is caused by the action of torque, thermal deformation, the action of the magnetomotive force of the stator and rotor, rotor imbalance, etc.

All this causes the risk of kinks of the rods at the place of their soldering into short-circuiting rings, as well as the sparking of the rotor cell, which leads to erosion of the surface of the rods.

As a prototype, the closest analogue was selected, which coincides with the utility model for most of the essential features. The prototype is a rotor of an induction motor, containing a magnetic core fixed in the form of a core with grooves fixed to the shaft. A short-circuited copper cast metal winding is placed in the grooves of the core (2).

This design of the rotor of an induction motor eliminates the above disadvantages of the analogue.

However, the disadvantage of such short-circuited windings is the complexity of their manufacture and low operational reliability. Copper, due to its low fluidity (2.7 times less than aluminum), makes it difficult to use for pouring short-circuited copper cast metal windings. The result is an insufficient density of the casting of the winding and porosity is formed during cooling. In this case, significant

decrease in electrical conductivity and thermal conductivity of copper in the winding due to the presence of deoxidizers and degassers introduced into the melt in it.

The objective of the proposed utility model is:

- improving the manufacturing technology of short-circuited windings of the rotor of an induction motor by increasing ductility and improving the casting properties of copper cast metal;

- increase the resource and increase the operational reliability of the induction motor by increasing the electrical and thermal conductivity, as well as increasing the density of copper cast metal of short-circuited rotor windings;

- reduction of harmful noise and vibration.

The problem is solved as follows.

Similarly to the known, the inventive rotor of an induction motor, contains a magnetic circuit fixed to the shaft in the form of a core with grooves. A short-circuited winding made of cast copper is placed in the grooves.

But unlike the prototype, in the inventive rotor of the induction motor, alloying elements are additionally introduced into the copper cast metal of the short-circuited winding - lead, tin, bismuth, antimony and nickel. In the metal of such an alloy, the copper content is 98.80-99.95%.

The essential features of the utility model listed above, other than the prototype, are necessary and sufficient in all cases to which the scope of legal protection of the utility model applies.

The use of alloying elements of lead, tin, bismuth, antimony and nickel in the manufacture of copper cast short-circuited windings can improve the technological quality of its manufacture. They increase fluidity, reduce the linear and volumetric shrinkage of the copper melt when pouring it into the grooves of the rotor magnetic circuit.

In addition, the introduction of lead significantly reduces harmful noise and vibration of the induction motor. Lead increases the damping ability of the winding alloy by increasing the heterogeneity of the structure. Lead is not soluble in copper and does not interact with the components that make up the alloy, and therefore is present in the structure in the form of separate evenly distributed independent inclusions.

The presence of soft lead inclusions in the structure of an alloy of a short-circuited winding sharply increases the damping ability due to the dissipation of the energy of elastic mechanical vibrations on the processes of microplastic deformation in these inclusions.

It is proposed that the short-circuited winding be made of copper containing silver, while the proportion of silver in this amount should not exceed 0.015%. This increases the electrical and thermal conductivity of the short-circuited rotor winding.

A short-circuit winding is also proposed in which the content of alloying elements does not exceed 1.2-0.05%, while the content of individual alloying elements is not standardized.

This content of components in a short-circuited winding provides a significant increase in its electrical conductivity and thermal conductivity without reducing mechanical and casting properties.

The manufacture of the inventive rotor of an induction motor is as follows. From the stamped sheets of electrical steel, the rotor magnetic core is formed in the form of a core with grooves.

The copper charge is loaded into an induction furnace. Alloying elements are introduced into molten copper through fluxes; lead, tin, bismuth, antimony and nickel.

The resulting melt is poured into the rotor core of an induction motor to obtain a monolithic winding design of conductive copper rods interconnected by short-circuiting rings. After cooling, the finished rotor core is mounted on the shaft of the induction motor.

The proposed rotor of an induction motor is characterized by high electrical conductivity and manufacturability of manufacturing short-circuited windings. This is ensured by a low degree of alloying of the copper alloy and a favorable combination of components.

Information sources:

1. USSR author's certificate No. 472423, cl. H02K 3/06, 1975.

2. Shirnin I.G., Chuvashev V.A., Gusarov A.A. Copper rotor windings of coal combine electric motors // Collection of scientific works of VNIIVE. - Donetsk. 1981. - S. 32-36 (prototype).

Claims (3)

1. The rotor of an asynchronous motor, containing a magnetic core fixed in the form of a core with grooves and a short-circuited copper cast metal winding placed in the grooves, characterized in that alloying elements are additionally introduced into the copper cast metal of the winding - lead, tin, bismuth, antimony and nickel while in the metal of such an alloy the copper content is 98.80-99.95%. 2. The rotor of an induction motor according to claim 1, characterized in that the short-circuited winding is made of copper containing silver, while the proportion of silver in this amount should not exceed 0.015%. 3. The rotor of an induction motor according to claims 1 and 2, characterized in that the content of the alloying elements in the short-circuited winding does not exceed 1.2-0.05%, while the content of individual alloying elements is not standardized.