Evaluation of a Bearingless PM Motor With Wide Magnetic Gaps

Abstract

A new non-contact drive system has been developed employing a consequent-pole type bearingless permanent magnet (PM) motor and a thrust magnetic bearing. This bearingless motor has a wide magnetic gap. The wide magnetic gap may cause a decrease in radial magnetic suspension force because of an increase in magnetic reluctance. A thrust magnetic bearing is installed at the end of the shaft, because strong thrust force exists in centrifugal pump applications. In this paper, the magnetic suspension forces and rotation characteristics of the experimental prototype are evaluated, while the rotor is magnetically suspended. Experimental results are also compared to the calculated ones using the finite element method. It is demonstrated that the developed consequent-pole type bearingless PM motor possesses sufficient magnetic suspension force for non-contact operation.

Integrated Design of a High Speed Magnetic Levitated Brushless Direct Current Motor System

“…Besides, this principle has also been applied for deduction of magnetic force of CRAMB in the followings. As a result, the total magnetic radial levitated force can be got by Formula (2), which is deduced from (6). Calculation values of current stiffness and position stiffness at rotor center position are 180 N/A and 587.1 N/mm respectively.…”

“…Outer diameter of axial window (mm) 112 d 6 Outer diameter of thrust disk (mm) 75 d 7 Inner diameter of axial window (mm) 65 l 1 The axial length of radial stator (mm) 16.5 l 2…”

“…Length of magnetic guide ring (mm) 5 l 3 The PM length in its magnetized direction (mm) 8 l 4 The axial length of side plate of axial stator (mm) 3.8 l 5 The axial length of axial window (mm) 13.2 l 6 Axial length of inner side gap of axial stator (mm) 2.1 l 7 The width of radial magnetic pole (mm) 32…”

“…High speed maglev electric motors are widely and increasingly applied in various industrial applications [5][6][7][8][9]. The advantages gained by such high-speed motors with AMBs are that of being able to increase efficiency and reliability by removing bearing lubrication and suppressing rotor vibration, resulting in decrease of sizes [7].…”

Design and Analysis of Novel Bearingless Permanent Magnet Synchronous Motor for Flywheel Energy Storage System

“…It not only generates electromagnetic torque, but also produces magnetic forces to suspend its rotor without mechanical contact. The motor has the advantages of no friction, no wear, high speed and long lifespan, which is suitable for being used in the FESS [7][8][9].…”