High starting torque direct line operated energy efficient motor

Abstract

The high efficiency motor employing the principle of three phase induction motor and permanent magnet synchronous motor includes a stator assembly and a rotor assembly. The rotor assembly includes a rotor shaft, a rotor stack assembly, a rotor cover and end ring. The rotor stack assembly includes a stamping stack, a conductor bar and a magnet. The stamping stack has dedicated slots for the conductor bar and the magnet. The rotor cover is fitted on the rotor stack, wherein both axial ends of the rotor cover are closed by end rings.

Claims

1. A high efficiency motor, comprising: a stator assembly having a stator winding; and a rotor assembly, being rotatable within said stator assembly, wherein said rotor assembly comprises: a rotor shaft; a rotor stack assembly having a stack longitudinal axis; a rotor cover having a first axial end and a second axial end opposite said first axial end; a first end ring connected to said first axial end of said rotor cover; and a second end ring connected to said second axial end of said rotor cover so as to enclose said rotor stack assembly within said rotor cover, said first end ring, and said second end ring, wherein said rotor stack assembly comprises: a stamping stack having an outer periphery; a plurality of magnet slots, each magnet slot having an outer side facing toward said outer periphery and an inner side facing away from said outer periphery, each magnet slot having a magnet arc shape being offset radial from said stack longitudinal axis; a plurality of bar slots, each bar slot having a set position during rotation of said rotor assembly along said outer periphery relative to said magnet slots, each bar slot being radial to said stack longitudinal axis and having a variable offset radial distance from said magnet arc shape of a respective magnet slot according to said set position; a plurality of conductor bars within respective bar slots so as to form a starting torque of the rotor assembly from a rotating magnetic field producing current in said conductor bars; and a plurality of magnets within respective magnet slots, wherein each magnet slot has a defined interval-x corresponding to a minimum magnet slot distance between each magnet slot and an adjacent magnet slot, wherein each magnet has a defined distance-y corresponding to a minimum magnet distance between said outer periphery of the stamping stack and each magnet within a respective magnet slot at a corresponding outer side, wherein said defined interval-x ranges from two to ten times said defined distance-y so as to form a partial starting torque with current through said conductor bars, and wherein all bar slots have a bar arc shape radial to said stack longitudinal axis.

2. The motor as claimed in claim 1, wherein said plurality of magnets is comprised of a first plurality of magnets in one respective magnet slot, and a second plurality of magnets in another respective magnet slot.

3. The motor as claimed in claim 1, wherein at least one magnet has a magnet curved cross section normal to said stack longitudinal axis, and wherein a respective magnet slot of said at least one magnet has a slot curved cross section normal to said stack longitudinal axis.

4. The motor as claimed in claim 1, wherein said stamping stack has a notch along said stack longitudinal axis.

5. The motor as claimed in claim 1, wherein each conductor bar is comprised of a material selected from a group consisting of Aluminum and Copper.

6. The motor as claimed in claim 1, wherein said rotor cover is comprised of a material selected from a group consisting of: Ferrous Metal, Aluminum, Aluminum Alloy, Copper, Copper Alloy, Zinc, Zinc Alloy, Lead, Lead Alloy, Chromium, Chromium Alloy, Nickle, Nickle Alloy, Tin, Tin Alloy, Silver, and Silver Alloy.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 illustrates the Exploded View of the Rotor Assembly

(2) FIG. 2 depicts the Isometric Sectional View of the Rotor Assembly

(3) FIG. 3 illustrates the Sectional View of Rotor Assembly

(4) FIG. 4 illustrates the Isometric Sectional View of Stack Assembly

(5) FIG. 5 depicts the Sectional View of second embodiment of Rotor Stack Assembly

DETAILED DESCRIPTION OF THE INVENTION

(6) The present invention relates to a self-start synchronous motor designed for providing high starting torque. The method of starting the motor involves the principle of three phase induction motor and the motor runs on the principle of permanent magnet synchronous motor. The motor operates by said methods by using a rotor having cage bars with reduced cross section that provides high starting torque and the magnet placed in the rotor to enable the rotation of the motor at synchronous speed.

(7) The present invention relates to a motor, said motor comprising of: a stator assembly; a rotor assembly (2); wherein said rotor assembly comprises of a rotor shaft (3); a rotor stack assembly (7) having a stack longitudinal axis or longitudinal axis (12), a rotor cover (5) and an end ring (6). The rotor stack assembly (7) further comprises of a stamping stack (4), a magnet (8); and a conductor bar (9). The stamping stack (4) provides slots (10,11) (such as bar slots 10 and magnet slots 11 as in FIG. 3) for the conductor bars (9) and the magnets (8) respectively.

(8) The magnet (8) is placed in a radially symmetrical manner in the stamping stack (4) having an outer periphery (4A). The magnet slots (11) that are provided towards the inner peripheral portion are at defined interval-x. Each magnet slot has an outer side (11A) facing toward the outer periphery and an inner side (11B) facing away from the outer periphery, as in FIG. 3. Each magnet slot has a magnet arc shape radial to the stack longitudinal axis (12), as in FIG. 3. The interval-x may vary from two to ten times the distance-y, wherein y is the minimum distance between the outer periphery of stamping stack and the edge of the magnet (8).

(9) According to the invention, said rotor cover (5) is fitted on the rotor stack (7) and the end rings (6) covers both axial ends of the rotor cover (5). The rotor cover (5) includes a first axial end (5A) and a second axial end (5B) opposite the first axial end as in FIG. 1. The end rings (6) include a first end ring (6A) connected to the first axial end of the rotor cover, and a second end ring (6B) connected to the second axial end of the rotor cover so as to enclose the rotor stack assembly within the rotor cover, the first end ring, and the second end ring as in FIG. 1.

(10) The magnet (8) and the slot (11) have a curved cross section normal to the longitudinal axis (12) of the rotor stack, wherein stamping stack (4) has a notch (1) along the longitudinal axis (12). The curved cross section is offset radial from the longitudinal axis (12) as in the embodiment of FIGS. 3-4. All the slots (10) filled with conductor bar have a common inner end radius, that is, each bar slot has a set position along the outer periphery radial to the stack longitudinal axis, while the magnet arc shape of a respective magnet slot varies.

(11) The material of the said conductor bar is selected from a group consisting of aluminum, aluminum alloy and copper, copper alloy.

(12) Said rotor cover (5) may be prepared from materials including, not limiting to, Ferrous Metal, Aluminum, Aluminum Alloy, Copper, Copper Alloy, Zinc, Zinc Alloy, Lead, Lead Alloy, Chromium, Chromium Alloy, Nickel, Nickel Alloy, Tin, Tin Alloy, Silver, Silver Alloy.

(13) Said slot (10) forms a shape of, not limiting to, Round, Pear, Oval, Oblong, Elliptical, Square, Rectangle, Triangle, Equilateral Polygon, Equiangular Polygon, Regular Polygon, and Irregular Polygon.

(14) Said slot (11) possesses a shape, not limiting to, Arc shape, Semi Hexagon Profile, Semi Octagon Profile, Semi Decagon profile, Semi Polygon Profile that is adapted to the shape of the magnet (8).

(15) A number of the magnets (14) are placed in slot (13) to form a shape of, not limited to, arc and trapezoid.