RU128414U1 - ELECTRIC MACHINE STATOR WITH COOLING SYSTEM - Google Patents

Abstract

1. The stator of an electric machine with a cooling system, comprising a housing inside which sealed cavities are formed, intended for forced circulation of the refrigerant pumped into them, sections of the frontal parts of the windings and a magnetic circuit are placed in the cavities, in which axial channels of circular or ellipsoid cross-sectional shape are made, characterized the fact that the zone of placement of the centers of the channels located along the axis of each of the teeth is limited, on the one hand, by the radius of the bases of the teeth, and on the other, by the radius, at which the smallest distance from the inner surface of the channel to the groove adjacent to the tooth is less than or equal to the width of the tooth in the base. 2. The stator of an electric machine with a cooling system according to claim 1, characterized in that in the cavity between the housing and the outer surface of the frontal parts of the winding sections, a coolant flow former is installed that is tightly adjacent to the outer surface of the frontal parts of the winding sections to form a channel for the refrigerant to pass into the axial channel .

Description

The utility model relates to the field of electrical engineering and can be used to create electric machines with intensive cooling of the stator.

Electric machines are known, the operation of the stator cooling systems of which is based on the use of direct heat removal from its most heated parts using flowing refrigerant. A device operating according to this principle is an electric machine, the stator of which contains a housing, inside of which are sealed cavities with a magnetic circuit and sections of windings placed in them (RU 2379813 C1, H02K 9/08, 2006). A disadvantage of the known technical solution is the low efficiency of heat removal from the frontal parts of the windings and the magnetic circuit, which is explained by the insufficient speed of the refrigerant flowing around them and the remoteness of the heat transfer region from the groove part of the windings.

The device closest to the utility model is an electric machine with an intensive stator cooling system (A. Alekseev, “Designs of electrical machines”, Leningrad, 1958, from 44-45). The stator contains a housing, inside of which sealed cavities are formed, interconnected into a single hydraulic path through which refrigerant is pumped under pressure. In the cavities there are sections of the frontal parts of the windings and a magnetic circuit with axial ventilation channels.

When using a similar technique for cooling the stator elements in high-speed electric machines that require more intensive cooling of its heat-generating elements, an increase in the efficiency of heat removal is possible due to an increase in the number of ventilation channels or their diameter. However, this path is limited by the permissible cross section of active iron for the passage of magnetic flux, the value of which can be increased only by increasing the cross section of the tooth zone or yoke, which leads to a deterioration in the mass of overall dimensions of the machine.

The technical result that can be achieved in the implementation of the utility model is to increase the cooling efficiency of the stator elements while maintaining its optimal mass overall dimensions.

The technical result is achieved due to the fact that in the stator of an electric machine with a cooling system containing a housing, inside which are sealed cavities designed for forced circulation of the refrigerant pumped into them, sections of the frontal parts of the windings and a magnetic circuit are arranged in the cavities, in which axial channels are made round or an ellipsoidal cross-sectional shape, the area of the center of the channels located along the axis of each of the teeth is limited, on the one hand, the radius is based teeth, and on the other, the radius at which the smallest distance from the inner surface of the channel to the groove adjacent to the tooth is less than or equal to the width of the tooth at the base. In addition, in the cavity between the casing and the outer surface of the frontal parts of the winding sections, a coolant flow former can be installed that is tightly adjacent to the outer surface of the frontal parts of the winding sections to form a channel for the refrigerant to pass into the axial channel.

Figure 1 presents a structural diagram of the stator.

Figure 2 shows a cross section of a stator.

The device (Fig.1, 2)) contains a housing 1, inside of which a sealed cavity is formed with a refrigerant circulating inside it. A magnetic circuit 2 with windings 3 is installed in the cavity. Axial channels 4 are made in the magnetic circuit 2, the number of which is equal to the number of stator teeth. To increase the cooling intensity (by increasing the speed of movement of the refrigerant in the ventilation ducts) in the cavity between the housing 1 and the outer surface of the frontal parts of the sections of the windings 3, a shaper of flow of refrigerant 5 is installed, which is tightly adjacent to the outer surface of the frontal parts of the sections of the windings, with the formation of a channel for the passage of refrigerant in corresponding axial channel 4.

The shaper flow 5 can be made of various (electrical and magnetic properties) materials, however, it is most advisable to give preference to non-magnetic non-conductive materials, such as plastics. This circumstance is explained by the fact that the use of magnetic materials leads to an increase in the coefficient of magnetic scattering of the frontal parts of the windings, and conductive to an increase in losses due to eddy currents in the shaper. In addition, the material of the former must be resistant to possible destructive effects from the refrigerant.

The device operates as follows.

When the electric machine is operating, refrigerant circulates in the cavities of the stator housing 1. At the active axial length of the stator, the refrigerant moves along the channels inside the magnetic circuit, located as close as possible to the tooth zone. The placement of the channels, their size and distance to the grooves of the stator (Figure 2) is determined from the condition of maximum conservation of magnetic flux in the magnetic circuit.

With rectangular grooves, the teeth having a trapezoidal shape allow you to use part of their section (in the region of the largest base) under the ventilation ducts. If the tooth section is not enough to accommodate the channel, then the channel is located along the axis of the tooth in the yoke region as close to the tooth zone.

It was experimentally established that in order to achieve the maximum result, it is most advisable to limit the area of the center of the channels 4, on the one hand (from below) the radius of the base of the teeth, and on the other (from above), by the radius at which the smallest distance from the inner surface of the channel to the groove adjacent to the tooth ( K) less than or equal to the width of the tooth in the base (B) (Figure 2).

Due to the fact that the magnetic flux, circling the channel, involves a part of the tooth section, the necessary increase in the yoke to maintain the magnetic flux is minimal.

The shape of the channels can be different and is selected based on the calculation of the magnetic field in the magnetic circuit. The most appropriate implementation of the channels - round or ellipsoidal cross-sectional shape.

Thus, the placement of ventilation ducts in the tooth zone or in the immediate vicinity of the windings made it possible to increase the cooling efficiency of the windings and the magnetic circuit and increase the reliability of the electric machine without affecting its mass overall dimensions.

Due to the high reliability of the operation of the stator fuel elements, provided by their sufficient cooling efficiency at the optimum mass and overall dimensions, a utility model may be most preferable when designing electric machines for general purposes.

Claims (2)

1. The stator of an electric machine with a cooling system, comprising a housing inside which sealed cavities are formed, intended for forced circulation of the refrigerant pumped into them, sections of the frontal parts of the windings and a magnetic circuit are placed in the cavities, in which axial channels of circular or ellipsoid cross-sectional shape are made, characterized the fact that the zone of placement of the centers of the channels located along the axis of each of the teeth is limited, on the one hand, by the radius of the bases of the teeth, and on the other, by the radius, at which the smallest distance from the inner surface of the channel to the groove adjacent to the tooth is less than or equal to the width of the tooth at the base. 2. The stator of an electric machine with a cooling system according to claim 1, characterized in that in the cavity between the housing and the outer surface of the frontal parts of the winding sections, a coolant flow former is installed that fits tightly on the outer surface of the frontal parts of the winding sections, with the formation of a channel for the passage of refrigerant in axial channel.

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