CN101488692A - Three-winding single phase induction motor of novel connecting method - Google Patents

Abstract

The invention discloses a three-winding single-phase induction motor with a new connection method. It adopts the method of connecting the stator winding of the motor to the capacitor, which can make the efficiency of the three-winding single-phase induction motor close to that of the three-phase symmetrical operation motor in single-phase operation, and is higher than that of ordinary single-phase induction motors with the same capacity. Its structure is as follows: it includes a machine base, a rotating shaft is installed in the machine base, a rotor is installed on the rotating shaft, and a stator core is arranged in the machine base, and a stator winding is arranged on the stator core. There are three sets of stator windings, each The axes of the windings have a 120° electrical angle difference in space, and the six outlets of all the windings are respectively connected to two capacitors, and the currents in the three windings are kept close to a symmetrical state.

Description

Three-winding single-phase induction motor with new connection

technical field

The invention relates to a motor, in particular to a three-winding single-phase induction motor with a new connection method.

Background technique

Single-phase induction motors only need single-phase AC power supply and are widely used. In order to generate starting torque, the stator windings of ordinary single-phase induction motors generally use primary and secondary two-phase windings, which are orthogonal in space. When the rated power is greater than 0.5kW, it is uneconomical to use a single-phase induction motor. One of the solutions is to connect the three-phase induction motor to a single-phase power supply for operation. For the three-winding single-phase capacitor running motor converted from a three-phase asynchronous motor, the analysis method of its electromagnetic performance is the same as when the three-phase asynchronous motor is powered by a single-phase power supply, so there is a large negative sequence current in the motor , the motor runs asymmetrically.

Contents of the invention

The purpose of the present invention is to improve the efficiency of single-phase induction motors, and proposes a three-winding single-phase induction motor with a new connection method, which can make the efficiency of three-winding single-phase induction motors close to that of three-phase symmetrical operation in single-phase operation. The motor is higher than the common single-phase induction motor with the same capacity, and the iron core size is smaller than the common single-phase induction motor with the same capacity.

To achieve the above object, the present invention adopts the following technical solutions:

A three-winding single-phase induction motor with a new connection method, which includes a machine base, a rotating shaft is installed in the machine base, a rotor is installed on the rotating shaft, and a stator core is arranged in the machine base, and a stator winding is arranged on the stator core. , there are three sets of stator windings, the axes of each winding differ in space by 120° electrical angle, the six outlets of all windings are respectively connected to two capacitors, and the currents in the three windings are kept close to a symmetrical state.

The stator winding is composed of A-phase winding, B-phase winding and C-phase winding according to the Y-type solution, wherein the A-phase winding is connected in series with a capacitor I to form a branch circuit, connected to a single-phase power supply, and the C-phase winding is connected in parallel with another capacitor II Then it is connected in series with the B-phase winding to form another branch, which is connected in parallel to the capacitor I, the current in the capacitor II is the sum of the currents in the A-phase winding and the B-phase winding, and the current in the capacitor I is the sum of the B-phase winding and The sum of the currents in the C-phase winding.

The output end of the C-phase winding is not directly connected to the same-named ends of other windings.

Both ends of the machine base are provided with end covers, and one end of the machine base is also provided with a fan and a windshield.

The rotor is a squirrel cage rotor, which includes a rotor core and rotor guide bars.

The capacitor I and the capacitor II are installed inside or outside the casing.

The three-winding single-phase induction motor of the novel connection mode of the present invention comprises a frame, a shaft is installed in it, a stator is installed in the frame, a rotor is installed on the shaft, and the rotor is basically the same as a common induction motor, which is a squirrel cage There are three-phase windings on the rotor and the stator of the motor, and the axes of the windings are 120° electrical angle different from each other in space. A special connection method is adopted, and two capacitors are connected externally. Both ends of the casing are provided with end covers and fans.

In the present invention, the stator winding of the motor has 3 sets of windings, with a spatial difference of 120° in electrical angle, and the six outlets of the windings are respectively connected with two capacitors, and the phase A winding is connected in series with a capacitor I to form a branch circuit, which is connected to a single-phase power supply, C The phase winding is connected in parallel with another capacitor II and then connected in series with the B-phase winding to form another branch, which is connected in parallel to the capacitor I. The current in the capacitor II is the sum of the currents in the A-phase winding and the B-phase winding, and the current in the capacitor I is the sum of the currents in the B-phase winding and the C-phase winding. Its basic working principle is as follows: Since the C-phase winding is incorporated into the capacitor II, and the B-phase winding and the C-phase winding are incorporated into the capacitor I, the current phase of the B-phase winding lags behind, the C-phase winding current phase leads, and the A-phase winding current phase remains unchanged. , so that the currents in the three windings maintain a symmetrical state, so that the motor basically achieves close to symmetrical operation.

The beneficial effect of the invention is that the structure is unique, the wiring method is simple, the size of the iron core can be effectively reduced, the efficiency of the motor can be improved, and energy can be saved.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic diagram of stator winding connection of the present invention;

Fig. 3 is a schematic diagram of stator wiring in the present invention.

Among them, 1—rotating shaft, 2—bearing, 3—end cover, 4—stator winding, 41—A phase winding, 42—B phase winding, 43—C phase winding, 5—frame, 6—stator core, 7—rotor Guide bar, 8—rotor core, 9—fan, 10—wind cover, 11—capacitor I, 12—capacitor II, 13—single-phase power supply.

Detailed ways

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

In Fig. 1, the three-winding single-phase induction motor of the new connection method includes a casing, the casing is provided with a frame 5, end covers 3 are provided at both ends of the frame 5, and a fan 9 is also provided at one end of the frame 5 Zephyr cover 10. A rotating shaft 1 and a bearing 2 are installed in the casing, and a rotor is installed on the rotating shaft 1. The rotor is a squirrel-cage rotor, which includes a rotor core 8 and a rotor guide bar 7. A stator core 6 is arranged inside the casing, and a stator winding 4 is arranged on the stator core 6. There are three sets of stator windings 4, which are A-phase winding 41, B-phase winding 42 and C-phase winding 43, as shown in Fig. 2 and Fig. 3 Show. A phase winding 41 is connected in series with a capacitor I11 to form a branch circuit, which is connected to the single-phase power supply 13. After being connected in parallel with another capacitor II12, the C phase winding 43 is connected in series with the B phase winding 42 to form another branch circuit. This branch circuit is connected in parallel with the capacitor I11. On I11, the current in the capacitor II12 is the sum of the currents in the A-phase winding 41 and the B-phase winding 42 , and the current in the capacitor I11 is the sum of the currents in the B-phase winding 42 and the C-phase winding 43 . In FIG. 3 , a, b and c are terminals with the same name of A-phase winding 41 , B-phase winding 42 and C-phase winding 43 respectively.

Claims (6)

1. A three-winding single-phase induction motor with a new connection method, which includes a machine base, a rotating shaft is installed in the machine base, a rotor is installed on the rotating shaft, and a stator core is also arranged in the machine base. The stator winding is characterized in that there are three sets of stator windings, the axes of each winding are at a certain electrical angle in space, the six outlets of all windings are respectively connected to two capacitors, and the currents in the three windings are kept close to a symmetrical state. 2. The three-winding single-phase induction motor of new connection method as claimed in claim 1, is characterized in that, described stator winding is made up of A-phase winding, B-phase winding and C-phase winding by Y-type solution, wherein A-phase winding It is connected in series with a capacitor I to form a branch, which is connected to a single-phase power supply; the C-phase winding is connected in parallel with another capacitor II and then connected in series with the B-phase winding to form another branch, which is connected in parallel to the capacitor I; the capacitor II The current is the sum of the currents in the A-phase winding and the B-phase winding, and the current in the capacitor I is the sum of the currents in the B-phase winding and the C-phase winding. 3. The three-winding single-phase induction motor with new connection method as claimed in claim 2, characterized in that, the output end of the C-phase winding is not directly connected to the same-named end of other windings. 4. The three-winding single-phase induction motor with new connection method as claimed in claim 1, characterized in that end covers are provided at both ends of the frame, and a fan and a windshield are also provided at one end of the frame. 5. The three-winding single-phase induction motor with new connection method as claimed in claim 1, characterized in that, the rotor is a squirrel-cage rotor, which includes a rotor core and rotor guide bars. 6. The three-winding single-phase induction motor with new connection method as claimed in claim 1 or 2, wherein the capacitor I and the capacitor II are installed inside or outside the casing.

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