Marvell International Limited

Agency for Science, Technology and Research

Rolls-Royce Corporation

Chao Bi

Quan Jiang

Song Lin

Nay Lin Htun Aung

Hla Nu Phyu

Amit Kumar Gupta

Zhimin Yuan

Bo Liu

Li Wang

Chun Lian Ong

Siang Huei Leong

Weiya Xi

Sivakumar Nadarajan

Khai Leong Yong

Jianzhong Shi

Chandana Jayamapathi Gajanayake

Kui Cai

Zhi Yong Ching

Pantelis Sophoclis Alexopoulos

Kheong Sann Chan

Qide Zhang

Budi Santoso

Jing Zhang

Moulay Rachid Elidrissi

Guchang Han

Chiew Leong Wong

Zhimin He

Jiang Feng Hu

Mengjun Liu

Tiejun Zhou

Leonard Gonzaga

Ke Gan

Wuzhong Lin

Wee Kiat Lim

Sufui Sophia Tan

Yansheng Ma

Shengkai Yu

Yin Quan Yu

Kannan Sundaravadivelu

Ningyu Liu

Jianqiang Mou

Boon Long Ibrahim See

Venkataramanan Venkatakrishnan

Song Ling

Cheng Peng Tan

Yin Qian Yu

Chong Wee Lee

Phyu Hla Nu

Wei Hua

Jiang Quan

Cheng Su Soh

A fault condition is diagnosed in an electric machine that includes a rotor and a plurality of permanent magnets. To do so, the rotor is rotated so that each of the plurality of permanent magnets passes a magnetic flux density sensor, and the values of magnetic flux density are measured using the magnetic flux density sensor at a plurality of positions of the rotor. The measured values of magnetic flux density are analyzed and a magnitude of a peak amplitude is compared in a time or frequency domain with a reference value. If the peak amplitude is below the reference value, the electric machine is determined to have a fault condition.

Method and apparatus for diagnosing a fault condition in an electric machine

According to an embodiment of the present invention, a data storage device comprising a motor having a stator is disclosed. The stator may include a substrate having a first surface and a second surface opposite to the first surface; and a n-phase winding arrangement having n phase windings; wherein each phase winding comprises m flat fractional-pitch coils arranged on the first surface of the substrate such that the coils are spaced apart uniformly along a closed loop and connected in series; wherein each coil together with an angular section of the substrate between the coil and an adjacent coil of the same phase winding defines a stator pole-pair; and wherein m is an integer larger than 1.

Data storage device

A method and system for controlling a motor is provided. In particular, various embodiments of the present disclosure describe a method and system for controlling a spindle motor in a hard disk drive (HDD) A method of controlling a motor is provided, the motor including a 3-phase synchronous motor with three terminals of an electromagnetic winding configuration. The method includes providing an input voltage between two of the terminals and measures a resultant silent terminal voltage at the third terminal, which is thereafter used in determining a rotor position. A corresponding system for controlling a motor is further provided.

Method and system for controlling a motor

A magnetic disk drive device for rotary driving a magnetic disk may be provided. The magnetic disk drive device may include a drive motor for rotary driving the magnetic disk. The drive motor may include a motor hub which has motor hub support portion with a screw-type motor hub engaging portion, and a motor hub support surface for supporting the magnetic disk. The magnetic disk drive device may also include a clamp disk including a clamp disk support portion with a screw-type clamp disk engaging portion complementary to the motor hub engaging portion, and a clamp disk support surface for supporting the magnetic disk.

Magnetic disk drive device, magnetic disk assembly and methods of forming the same

A low profile spindle motor for supporting and rotating media disk or disks of a hard disk drive includes a plurality of stator teeth, a winding layer which may be formed by printed circuit board or the like, and a rotor. The plurality of stator teeth are disposed in an annular region surrounding an axis of rotation of the motor, and have projected ends for increasing the tooth area facing a magnet ring of the rotor. The winding layer has a plurality of windings disposed surrounding the axis of rotation. Each winding is coupled to one of the plurality of stator teeth. The magnet ring is positioned radially spaced apart and coplanar with the annular region. The magnet ring has magnetic poles annularly distributed to generate magnetic fluxes along radial direction. Spindle motor formed according to the invention has a low profile, improved performance and manufacturability.

Low profile spindle motor

A runout measurement system is proposed for measuring the runout of a moving surface of a device having a rotating body, such as a mass storage device () (e.g. a hard disk drive) having a rotor which in use includes a rotating recording medium. A sensor () interacting with the moving surface obtains a displacement signal. The displacement signal is sampled by a sampling unit () controlled by a unit () which initiates sampling based on both a signal indicating a ZCP and the clock signal of a high frequency (e.g. 20 MHz) clock (). Simultaneously, the same clock () is used by a counterto measure the spacing between one or more ZCP times. This permits the correspondence between the sampling times and the angular position of the rotor to be found with a high accuracy which depends upon the clock frequency, and thereby allows calculation of repeatable runout (RRO) and non-repeatable runout (NRRO).

Runout measurement for devices having a rotating body

A low profile permanent magnet synchronous motor with segment structure. In accordance with this invention, a stator assembly for an electromagnetic motor is provided. The stator assembly has a first stator core and a second stator core that couple windings. Teeth extend outward from each stator core and through the windings to contact the other stator core.

Low profile permanent magnet synchronous motor with segment structure

Growing community of inventors

Singapore, Singapore

Chao Bi