CN101692593B - Dual-power induction motor for conveyor - Google Patents

Abstract

The invention provides a dual-power induction motor for a conveyor, including a rotor and a stator winding. Convertible wiring and turn reduction technology, with high and low power levels, the number of coils in series in each phase gradually decreases, the low power level corresponds to the most turns, the high power level corresponds to the least number of turns, and the high power level has a high start-up rotation It is used for heavy-load starting and running. After the starting process, it can maintain high-power operation or switch to low-power operation depending on the load condition. And according to the load change of the coal mine conveyor, two contactors can be used to realize the automatic switching of the dual power gears. Therefore, the dual-power induction motor for conveyors of the present invention has the characteristics of large starting torque, high operating efficiency and power factor, simple control, good reliability, significantly reduced no-load current, and better energy-saving effect.

Description

Dual Power Induction Motors for Conveyors

technical field

The invention belongs to the technical field of motors, in particular to a dual-power induction motor for conveyors.

Background technique

Belt conveyor is a mechanical transmission device widely used in coal mining in my country. Its dragging load changes continuously with the size of the conveying volume. Sometimes it runs with heavy load and sometimes it runs with light load. At the same time, many occasions also require the conveyor motor to have dual Voltage working capacity, in order to adapt to such load operating conditions, the motor is generally selected according to the requirements of heavy load operation. In this way, the actual load rate of the motor is small when the motor is running at light load, and the efficiency and power factor are low.

In order to solve the above problems, many technical solutions have been proposed at home and abroad, for example, high-slip motors, permanent magnet motors, double-stator motors, thyristors are also used to adjust and reduce voltage, variable frequency power supplies, reactive power compensation devices, and motor stator windings. -Δ connection, etc. However, these technical solutions have little improvement in performance, or the cost is too high, or the control conversion is complicated and the reliability is poor. Can not really meet the needs of my country's coal mine conveyors, in fact it is difficult to popularize and apply.

Contents of the invention

The purpose of the present invention is to provide a dual-power induction motor for conveyors with large starting torque, high operating efficiency and power factor, simple control, good reliability, significant reduction in current when no-load, and good energy-saving effect.

The technical solution adopted by the present invention to achieve the above purpose is a dual-power induction motor for conveyors, including a rotor and a stator winding. The stator winding uses segmented lead wires for each phase, and the internal connection is changed to apply two voltages, with high , two low power levels, the stator winding has 6 outlets, which are high power outlets (UH, VH, WH) and low power outlets (UL, VL, WL), the low power level corresponds to the most turns, the high The power gear corresponds to the minimum number of turns, and the Δ+Y or Y+Y wiring method is realized according to the internal connection conversion. The two power gear conversions described above are realized by two contactors; for the Δ+Y wiring method, if the three-phase power supply is from When the high-power outlets (UH, VH, WH) are connected, the three-phase windings are in Δ connection, corresponding to the high-power gear; if the three-phase power is connected from the low-power outlets (UL, VL, WL), then The three-phase winding is Δ+Y connection, which corresponds to the low power gear; for the Y+Y connection method, if the three-phase power is connected from the high-power outlet (UH, VH, WH), then the three-phase winding is Y connection , corresponding to the high-power gear; if the three-phase power supply is connected from the low-power outlet (UL, VL, WL), then the three-phase winding is connected in Y+Y, corresponding to the low-power gear.

Each phase of the stator winding of the motor is divided into three sections, which are distinguished by the subscripts "Δ, Y1, Y2". Each phase has 5 outlets, and there are 15 outlets in three phases, of which 9 outlets are used to change the internal connection of the winding. Realize that two applicable voltages can be drawn out as needed.

Since the dual-power induction motor used in the conveyor is designed for the heavy-duty starting and changing load operation characteristics of the coal mine belt conveyor, the turn-reducing technology based on the winding theory of the AC motor, through the vector analysis method in the winding design And the application of computer harmonic analysis method ensures that the windings corresponding to the two power levels have their own characteristics and have good performance, which can fully meet the working condition requirements of the conveyor load.

The invention belongs to the technical field of motors and provides an ideal dual-power induction motor for conveyors. Compared with the prior art, since the stator winding adopts the segmented lead method for each phase, it has the ability to meet the requirements of different load changes. Two gears can output voltage; because the stator winding adopts the unique technology of reducing the number of turns in series and the convertible wiring mode, it has two selectable high and low power gears, among which the high power gear has high starting torque and can be used For heavy load starting and running, after the starting process is completed, depending on the load condition, keep the high power gear running or switch to the low power gear running. And according to the change of the load condition of the coal mine conveyor, the automatic switching of the dual power gears can be realized, so that the motor operation system and the belt conveyor load system have a good matching performance. Therefore, the dual-power induction motor for conveyors of the present invention has the characteristics of large starting torque, high operating efficiency and power factor, simple control, good reliability, significantly reduced current when no-load, and better energy-saving effect.

Description of drawings

The structural features of the dual-power induction motor for conveyors of the present invention will now be further described in conjunction with the accompanying drawings.

Fig. 1 is the structural representation of motor stator winding Δ+Y connection of the present invention;

Fig. 2 is the structural representation of the motor stator winding Y+Y connection of the present invention;

Fig. 3 pole number 2p=4 of the embodiment of the present invention, the phase diagram of the stator winding of slot number Z=48;

Figure 4. The three-phase winding slot number of the standard 60° phase belt winding, that is, the schematic diagram of the low-power gear stator winding of the Y+Y connection method;

Figure 5 is a structural schematic diagram of the pole number p=2 and the number of slots Z=48 stator winding Δ+Y wiring in the embodiment of the present invention;

Fig. 6 is a schematic diagram of the structure of the stator winding Y+Y wiring with the number of poles p=2 and the number of slots Z=48 according to the embodiment of the present invention;

Figure 7 is a schematic diagram of the harmonic analysis of the magnetic potential of the three-phase winding with the number of poles 2p=4, the number of slots Z=48, and y=10.

Detailed ways

As shown in Fig. 1, the structure diagram of the Δ+Y connection of the motor stator winding of the present invention, and Fig. 2 the structure diagram of the Y+Y connection of the motor stator winding of the present invention, each phase of the new motor stator winding is divided into three sections with the subscripts "Δ, Y1, Y2 respectively. "Different, each phase has 5 outlet terminals, and there are 15 outlet terminals in three phases, of which 9 outlet terminals are used to change the internal connection of the winding, so as to realize two voltages as required; the other 6 outlet terminals are for connecting external three Phase-to-phase power supply for conversion of different power levels is distinguished by "UH, VH, WH" and "UL, VL, WL" respectively, indicating high and low power levels.

For the Δ+Y connection method, if the three-phase power supply is connected from the outlet terminals "UH, VH, WH", then the three-phase winding is connected in the Δ connection method, corresponding to high power gear; if the three-phase power supply is connected from the outlet terminals "UL, VL , WL" access, then the three-phase winding is Δ+Y connection, corresponding to low power gear.

For the Y+Y connection method, if the three-phase power supply is connected from the outlet terminals "UH, VH, WH", then the three-phase winding is Y connection, corresponding to high power gear; if the three-phase power supply is connected from the outlet terminals "UL, VL , WL" access, then the three-phase winding is Y+Y connection, corresponding to low power gear.

When the voltage level is determined, two contactors can be used to easily and reliably perform dual-power two-speed switching.

The above wiring method adopts the design idea of increasing the motor capacity by using the number of stator windings connected in series. "Reducing turns", that is, according to the distribution of motor capacity, the motor windings corresponding to two power levels are connected in series in each phase from high to low. The number of turns is gradually reduced, the low power gear corresponds to the most turns, and the high power gear corresponds to the least number of turns, so that there is the simplest and most reliable conversion method between each power gear, and it can also adapt to the load change of the conveyor to keep the motor running efficiently working condition requirements. Through the application of the vector analysis method and the computer harmonic analysis method in the winding design, the winding "turn reduction" technology ensures that the two power levels corresponding to the winding have their own characteristics and good performance, which can fully meet the load requirements of the conveyor. Working conditions.

Embodiment one

The embodiment is specifically described by taking the three-phase winding with the number of poles 2p=4 and the number of slots Z=48 commonly used in conveyors as an example. As shown in Figures 3, 4, 5, 6, and 7, Figure 3 shows the phase diagram of the stator winding with the number of poles 2p=4 and the number of slots Z=48 in Figure 3; Slot number, that is, the schematic diagram of the low-power gear stator winding of Y+Y connection;

On the basis of the standard scheme, according to the characteristics of the load condition of the conveyor, choose to remove 4 slot numbers for each phase, which are marked as "AΔ, BΔ, CΔ" in Figure 4, corresponding to the high-power three-phase winding slot number division scheme, three The phase winding coil can adopt Y connection or Δ connection to adapt to different voltage levels. The 4 slot numbers removed above need to be reconnected at low power levels, and the connection method can be determined by the connection method of the AΔ, BΔ, CΔ three-phase winding coils. If it is a Y connection, generally a single-channel series connection method is adopted, that is, a three-phase Y+Y connection method is formed. If it is a Δ connection method, a single-channel series connection method can generally be used in the case of a single voltage, but in a dual-voltage Under the circumstances, it is necessary to use a two-way parallel connection and then connect it in series with the Δ connection method to form a three-phase Δ+Y connection method. The division of two-way parallel slot numbers should pay attention to the balance of induced potential between the two lines.

In the low-power gear, that is, on the basis of the standard 60° phase-band winding, a part of the coil slot number is removed to increase the load capacity of the motor, thereby obtaining a high-power gear. However, harmonic analysis should be performed on all possible "reduced turns" winding schemes, and the final winding scheme required is screened according to the results of harmonic analysis.

As shown in Figure 7, the number of poles 2p = 4, the number of slots Z = 48, y = 10 is a schematic diagram of the harmonic analysis of the magnetic potential of the three-phase winding. The analysis results of the magnetomotive force harmonics from the analysis of the high-power gear winding scheme to the number of poles Z-p and the harmonic analysis results of the standard 60° phase-band winding corresponding to the low power gear are listed. It can be seen that when the coil pitch y=10, the winding coefficient of the high-power winding scheme after removing 4 slot numbers per phase is 0.9440, which is higher than the standard 60° phase winding coefficient of 0.9250, and The magnetic potential reversal component is 0, indicating that the three-phase winding is symmetrical at this time, and a high conductor utilization rate is maintained.

Secondly, considering that the high-power gear is mostly used to complete the starting process of the conveyor, it is also necessary to limit the amplitude of the high-order harmonics of forward rotation that are in the same direction as the 4-pole fundamental wave. The analysis shows that the relative amplitude of the larger high-order forward harmonic is only 2.4449% when the number of poles of the high-power gear winding is 52, not more than 4%. Therefore, according to such harmonic analysis results, and based on the general criterion of winding performance, it can be known that after losing some coils in each phase winding with appropriate "turn reduction" technology, the winding corresponding to the high power gear still maintains the same level as the standard 60° phase. Good performance with similar winding can meet the application requirements.

相比，更能适合大多数情况下电机负载的工况。As shown in Figure 5, the pole number p=2 of the embodiment of the present invention, the structural diagram of the stator winding Δ+Y connection with the number of slots Z=48; Figure 6 the embodiment of the present invention with the number of poles p=2, the number of slots Z=48 and the stator winding Y+Y Schematic diagram of the wiring structure; it can be seen that there are 16 coils per phase in the low-power range, and 12 coils in each phase in the high-power range. The design requires adjustment, obviously, such that the turns ratio value is related to the Y/Δ conversion turns ratio value

In comparison, it is more suitable for the working conditions of the motor load in most cases.

From this analysis, it can be seen that the new Δ+Y/Y+Y connection method adopted by the stator single winding structure of the present invention can adapt to two voltages, and the Δ+Y connection method or the Y+Y connection method ensures that the two power levels are only There are 6 outlet terminals, which can be switched by using two three-phase contactors. The control is extremely simple and reliable. The turn reduction technology based on the theory of AC motor wire groups, through the vector analysis method and computer tuning in the winding design The application of the wave analysis method ensures that the coils corresponding to the two power levels have their own characteristics and good performance, which can fully meet the needs of the conveyor load condition. Compared with the existing technology, it has the characteristics of large starting torque, high operating efficiency and power factor, simple control, good reliability, significant reduction in current when no-load, and better energy-saving effect. Because of its unique advantages, it will have a good application prospect in the field of energy saving of most motor systems, which has played a certain role in promoting the technological progress of our country in this technical field.

Claims (2)

1. A dual-power induction motor for conveyors has a rotor and a stator winding. It is characterized in that: the stator winding uses segmented lead wires for each phase, and the internal connection is changed to apply two levels of voltage. It has two power levels, high and low, and the stator winding It has 6 outlets, which are high-power outlets (UH, VH, WH) and low-power outlets (UL, VL, WL). The low-power gear corresponds to the most turns, and the high-power gear corresponds to the least turns. According to the internal The connection conversion realizes the Δ+Y or Y+Y wiring method, and the two power gear conversions are realized by using two contactors; for the Δ+Y wiring method, if the three-phase power supply is connected from the high-power outlet terminal (UH, VH, WH) access, at this time the three-phase winding is connected by Δ, corresponding to the high-power gear; if the three-phase power supply is connected from the low-power outlet (UL, VL, WL), then the three-phase winding is connected by Δ+Y , corresponding to the low-power gear; for the Y+Y connection method, if the three-phase power supply is connected from the high-power outlet terminal (UH, VH, WH), then the three-phase winding is Y-connected, corresponding to the high-power gear; if the three-phase The power supply is connected from the low-power outlet (UL, VL, WL). At this time, the three-phase winding is connected in Y+Y, corresponding to the low-power gear. 2. The dual-power induction motor for conveyors according to claim 1, characterized in that: each phase of the stator winding of the motor is divided into three sections, which are distinguished by the following subscripts "Δ, Y1, Y2", and each phase has 5 outlets , There are 15 outlets for the three phases, of which 9 outlets are used to change the internal connection of the winding, so that two applicable voltages can be drawn out as needed.

Images