CN105048744A - Cast copper rotor for variable frequency motor - Google Patents

Abstract

A cast copper rotor of a variable frequency motor, wherein a rotor iron core (5) of the rotor is formed by laminating a certain number of rotor sheets (1) of the same size and shape. The rotor sheet body (1) is a circular hollow structure, and the central part is a shaft hole (3) for installing the motor shaft. A certain number of closed guide bar holes (2) are evenly distributed on the circumference of the rotor sheet body (1), and the guide bar holes (2) are in an inverted trapezoidal structure with a wide top and a narrow bottom. The guide bar holes (2) on the rotor sheet (1) are stacked to form the guide bar grooves in the rotor core (5), and the copper liquid is poured into the guide grooves one by one, and is closely bonded to the rotor The cast copper end rings (4) at both ends of the iron core (5) form a whole, forming the cast copper squirrel cage structure of the rotor.

Description

Cast copper rotor of a variable frequency motor

technical field

The invention relates to a cast copper rotor of a variable frequency motor.

Background technique

With the increasing scarcity of energy, saving energy and reducing consumption has become an extremely urgent task facing the development of the international community. It is of great significance to develop an ultra-efficient motor system to ensure the full utilization and sustainable development of energy in our country.

In terms of reducing motor loss, copper has good electrical conductivity compared to aluminum. The cast copper rotor is a new type of motor rotor with copper as the conductive matrix. Using the excellent electrical conductivity of copper can reduce rotor loss and improve motor efficiency. However, although the efficiency of the power frequency cast copper rotor motor has been significantly improved, its starting current becomes larger and the starting torque becomes smaller, sometimes even exceeding the tolerance range of the asynchronous motor design standard.

From the point of view of the control mode of the motor, the variable frequency speed regulating motor has been widely used in various fields of modern industry due to its simple structure, convenient manufacture, low price, sturdy and durable, reliable operation, and simple maintenance. However, the frequency conversion speed control method makes the motor supply voltage contain a large number of high-order harmonics, which will cause increased motor losses, the most notable of which is the rotor loss.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the existing cast copper rotor motors such as small starting torque and large rotor loss of frequency conversion motors, and propose a cast copper rotor with high efficiency, good reliability and superior frequency conversion performance.

To achieve the above object, the present invention adopts the following scheme:

The cast copper rotor of the frequency conversion speed regulating motor of the present invention is composed of a rotor iron core and a cast copper squirrel cage, the cast copper guide bars of the squirrel cage structure are located in the guide bar grooves of the rotor iron core, and the cast copper end rings of the squirrel cage structure are located on both sides of the rotor iron core , and in close contact with the rotor core.

The rotor core is formed by laminating a plurality of rotor sheets with the same size and shape. A certain number of closed guide bar holes are evenly distributed along the circumference of the rotor sheet, and the guide bar holes adopt an inverted trapezoidal structure with a wide top and a narrow bottom.

Operating principle and working process of the present invention are:

The rotor of the invention is applied to a variable frequency speed regulating motor. When the motor is started, the frequency conversion speed control method is adopted. The rotor current and starting torque gradually increase steadily with the motor frequency from zero until it enters the rated working state, thus effectively avoiding the large starting current and small starting torque of the existing cast copper rotor. The problem.

The beneficial effects of the present invention are:

1. The rotor of the existing variable frequency speed regulating motor also has obvious deficiencies in the response of different frequency bands, and the rotor resistance shows a linear increase trend with the increase of frequency, which makes the motor seriously heated in the high frequency band. The cast copper rotor of the frequency conversion motor of the present invention utilizes the unique inverted trapezoidal cast copper guide bar to exert its excellent resistance characteristics in the low frequency or high frequency range, and the rotor resistance is low, thereby reducing rotor loss and improving motor efficiency; The rated frequency band exerts its superior conductive characteristics, and the rotor resistance is higher, thereby increasing the rotational torque of the motor and improving the operating performance of the motor.

2. Most of the existing motor rotors have a deep and narrow guide bar hole structure, which is affected by the skin effect. When the alternating current passes through the conductor, the current will be concentrated on the surface of the conductor, the utilization rate of the rotor bar is low, and the heat is serious. The present invention utilizes the inverted trapezoidal structure of the upper width and the lower narrowness of the rotor groove, so that the rotor current can be more evenly distributed in the entire cross-sectional area of the bar, effectively reducing the influence of the skin effect on the current of the rotor bar of the frequency conversion motor, and improving the efficiency of the rotor bar. Utilization, reduce rotor loss, improve motor efficiency.

Description of drawings

Fig. 1 is the front part sectional structure schematic diagram of the cast copper rotor of frequency conversion motor of the present invention, among the figure: 1 rotor sheet body, 2 guide bar holes, 3 shaft holes, 4 cast copper end rings, 5 rotor cores.

Fig. 2 is a side sectional schematic diagram of the cast copper rotor of the frequency conversion motor of the present invention, in the figure: 3 shaft holes, 4 cast copper end rings, 5 rotor cores, 6 cast copper guide bars.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in FIG. 1 or FIG. 2 , the rotor core 5 is formed by laminating a plurality of rotor laminations 1 of the same size and shape. The central circular hole structure of the rotor sheet 1 is laminated to form a shaft hole 3 for installing the motor shaft. A certain number of closed guide bar holes 2 are evenly distributed on the circumference of the rotor sheet 1. The guide bar holes 2 are in an inverted trapezoidal structure with a wide top and a narrow bottom. After lamination, a guide bar groove for pouring cast copper guide bars 6 is formed. The number of guide bar holes 2 is determined according to the performance requirements of the frequency conversion motor using the present invention, and the present embodiment is 26.

The cast copper guide bar 6 and the cast copper end ring 4 are die-cast to form an integral cast copper squirrel cage. The cast copper guide bars 6 are poured into the guide bar grooves of the rotor core 5, and the number of the cast copper guide bars 6 is the same as the number of the guide bar holes 2, 26 in this embodiment. The cast copper end rings 4 are respectively located at both ends of the rotor core 5 and are in close contact with the rotor core 5 .

Claims (4)

1. a cast copper rotor of variable frequency motor, it is characterized in that, described cast copper rotor is made up of rotor iron core (5) and cast copper squirrel cage; The cast copper guide bar of described squirrel cage structure is positioned at rotor iron core (5) In the guide bar groove, the cast copper end rings (4) of the squirrel cage structure are located on both sides of the rotor core (5), and are in close contact with the rotor core (5). 2. The cast copper rotor according to claim 1, characterized in that, the rotor core (5) is formed by laminating a plurality of rotor sheets (1) of the same size and shape; (1) is a circular hollow structure, and closed guide bar holes (2) are uniformly distributed along the circumference of the rotor body (1). 3. The cast copper rotor according to claim 1, characterized in that, the guide bar hole (2) adopts an inverted trapezoidal structure with a wide top and a narrow bottom. 4. The cast copper rotor according to claim 1, 2 or 3, characterized in that: the cast copper guide bar (6) of the cast copper squirrel cage and the cast copper end ring (4) are die-casted and connected as a whole, and the cast copper The copper guide bars (6) are poured into the guide bar slots of the rotor core (5), and the number of cast copper guide bars (6) is the same as the number of guide bar holes (2).