Abstract: A labyrinth seal system of the present invention is found in a motor having a ball bearing ring, a shaft, and a labyrinth seal washer. The ball bearing ring has an inner bearing ring with an inner ring surface. In one embodiment the labyrinth seal system includes a shaft having a first shaft portion with a first shaft diameter and a second shaft portion with a second shaft diameter. The first shaft portion has a first outer shaft surface and the second shaft portion has a second outer shaft surface. A shaft shoulder may be formed between the first and second outer shaft surfaces. The second outer shaft surface is at least partially annularly adjacent the inner ring surface. Also included is a labyrinth seal washer having an annular leg that is positioned at least partially between the first outer shaft surface and the inner ring surface. The labyrinth seal system includes turbulence zones interspersed with narrow flow zones.

Abstract: A conical bearing system includes a first conical bearing having an integral shaft and a second conical bearing defining a bore having a shaft mating bore section and a threaded bore section. The system is assembled by applying adhesive to the shaft and inserting the shaft into the shaft mating bore section. A threaded screw is then screwed into the threaded bore section until the screw abuts the shaft. Then torque is applied to the screw to push against the shaft thereby causing the second conical bearing to move axially. Once the adhesive has cured, the screw may optionally be removed.

Abstract: An apparatus for making permanent magnet material magnetizes a body of material including a primary winding which has portions wound on a first core carrying current in a first direction creating a first field of flux and a secondary winding having portions wound on a second core wherein the secondary winding carries current in a second opposing direction to create a second field of flux. Since the currents are flowing in opposing directions, the secondary field of flux is directed to oppose the first field of flux. The result of this is that the magnetizer is capable of controlling the width of the pole to pole transition region for matching the stator geometry and thereby nearly eliminating cogging torque and reducing ripple torque.

Abstract: A construction for an electric spindle motor includes a stationary central shaft with a horizontal thrust bearing plate and a rotating hub assembly. A flanged thrust bearing ring having an upper capillary surface is affixed to the hub assembly. An annular end cap having a lower capillary surface is nested within the flanged bearing ring. The upper and lower capillary surfaces are radially outwardly diverging horizontal surfaces relative to each other which define a capillary cavity. Lubricating fluid partially fills the capillary cavity to form a horizontal capillary seal which prevents the fluid from escaping the motor. The capillary seal may be formed by tapering either the upper or lower capillary surfaces to provide an enlargement of the bearing cavity in an axial direction radially outwardly from the central shaft. Alternatively, the capillary seal may be formed by substantially coating the upper and lower capillary surfaces with a barrier coating to increase surface tension.

Abstract: A connector for use in an electric motor includes a one piece flex circuit for connecting the stator coils of a motor to a set of terminals outside the motor. The circuit includes an elongate thin narrow and flexible lead portion supporting a set of parallel circuit runs where each of the circuit runs terminates in a solder pad. The solder pads are located adjacent one another at a tip of the flex circuit and the tip is affixed atop one of the stator core teeth. A land portion at the opposite end of the flex circuit includes arms supporting contact terminals arranged radially around the base of the motor.

Abstract: A construction for a fluid bearing in a rotary spindle apparatus includes a spindle having first and second ends, and at least one thrust plate coupled to a shaft which is surrounded by a hub having an enclosing sleeve. The sleeve surrounding the thrust plate and shaft defines several gap regions where bearing fluid resides. A first radial gap region is defined between the shaft and sleeve and a second radial gap region is defined between the outer diameter of the thrust plate and the sleeve. A first axial gap region is defined by an upper surface of the thrust plate and the sleeve, and a second axial gap region exists between the lower surface of the thrust plate and the sleeve. A bearing fluid is disposed within these gap regions and forms capillary seals at first and second ends of the spindle. The thrust plate includes holes or pressure compensation ports which connect the first and second axial gap regions.

Abstract: An electric motor construction includes a rotor housing and sleeve which surrounds a shaft/thrust plate. The thrust plate is enclosed in a dead end cavity and is surrounded by a fluid which forms a fluid bearing. The shaft has asymmetrical grooves which create a net pressure gradient from a capillary seal formed near the bottom of the shaft toward the dead end cavity. This helps maintain the capillary seal and reduce the risk of cavitation.

Abstract: A control circuit and method for controlling an electric machine has a plurality of stator windings energized by current signals. The control circuit includes a driver circuit that generates three pulse width modulated current signals responsive to an error signal that is representative of a phase angle error, where each of the respective current signals is one phase of a three phase signal. The driver circuit also generates phase information associated with the current signals. The machine has three input terminals each of which receives a respective one of the three current signals generated by the driver circuit. A multiply circuit multiplies the terminal voltage of at least one of the three terminals with the phase information to generate the error signal.

Abstract: A press fit machine for assembling an electric motor which includes a hub having an upper bearing and a stator assembly having a lower bearing, includes an upper and lower press fit fixtures for holding the hub and stator respectively in a preloaded condition prior to motor assembly and for a predetermined period of time afterward. The machine press fits the two halves of the motor together while maintaining appropriate preloads on the upper and lower bearings to prevent excess looseness in the bearings or excessive stiffness. The preload ensures that the bearing will function correctly after assembly because it is maintained during a period of time that the glue joining the hub and stator assembly together sets.

Abstract: A low noise, high bandwidth, sensorless vector control for a brushless DC motor includes a phase locked loop control having a digital counter and ROM look-up table which is responsive to a VCO to generate digital signals representing the sine and cosine of the instantaneous phase angle of the VCO. These signals are modulated by a current command and applied to a two-phase to three-phase converter. A flux sensor senses the air gap flux in the three motor coils and converts this signal to quadrature components which are compared with the output of the look-up table to derive a phase error signal that drives the VCO. Another feature of the invention is a timed self-starting network that cause the VCO frequency to ramp upwards then automatically switch to loop control without any abrupt change in the frequency of the VCO.

Abstract: A motor control circuit for a switched reluctance motor which includes a rotor and a plurality of stator coils, and a driver circuit for energizing the coils in sequence, includes a current sensing resistor for detecting a signal proportional to the current in the coils and a slope detector for detecting the rate of change of the current signal with respect to time over predetermined time intervals during which the voltage in the coils is dominated by a term representing back EMF. A variable oscillator is responsive to an integrated output of the slope detector for generating a timing signal for the driver circuit. When the voltage across the coils is dominated by the back EMF term, the current should be substantially constant, but when the rotor is out of phase with the driver circuit, the current signal during this time has a substantially linear slope which is either positive or negative depending upon whether the rotor is leading or lagging the driver circuit.

Abstract: A sensorless control for DC permanent magnet brushless motor includes a feedback loop connected between the motor stator windings and the inverter which controls the timer at which current is provided to the various windings in sequence. The control of the invention includes a voltage sensing network for sensing the back EMF on each motor winding when it is unenergized and comparing this voltage with a null point. For maximum torque this voltage has an optimum value and variation from this value produces an error signal which is integrated to produce a VCO drive signal. This signal controls the frequency of a VCO which in turn controls the switching times of the inverter.

Abstract: A compact three-phase permanent magnet rotary machine having minimal reluctance torque and electromagnetic torque ripple, and maximum energy efficiency and starting torque per unit volume of winding, comprises an armature having 3(2n+1) ferromagnetic poles and slots and a permanent magnet assembly having 3(2n+1).+-.1 permanent magnet poles, where n is an integer of 1 or more. Each of the three phases of the winding comprises multiple coils, each wound about a respective ferromagnetic pole and occupying a pair of slots located immediately on each side of a respective pole. The coils of a particular phase are located within a sector of the circular array of ferromagnetic poles encompassing 2n+1 poles.

Abstract: A tachometer or accelerometer features a nonmagnetic, electrically-conductive, moving member whose velocity or rate of change of velocity is to be measured. A magnetic field is generated in a direction generally perpendicular to the direction of motion, creating eddy currents in the moving member which, in turn, create an eddy current magnetic field. The flux density of the eddy current field is measured by a Hall effect sensor to produce a signal representative of velocity or, alternatively, the rate of change of flux density of the eddy current field is measured by a coil producing a signal representative of the rate of change of velocity. A separate magnetic circuit for the Hall effect sensor or coil sensor, as the case may be, is provided so as to maximize the strength of the eddy current field by concentrating the sensed eddy current flux and thereby maximizing the device's sensitivity and accuracy while minimizing its susceptibility to error through interference.

Abstract: A controlled force variable reluctance actuator. A variable reluctance actuator having a moving element operated by a solenoid is provided in which the current in the solenoid is controlled by a signal representative of the flux density in the magnetic circuit of the actuator. The signal is produced by a Hall effect device placed in the magnetic circuit. Preferably, the Hall effect device controls the current in the solenoid by controlling its duty cycle; however, continuous control of the current may also be employed. Alternative embodiments are provided for a constant force actuator, an actuator whose force-displacement characteristic is altered, and an actuator in which the force may be selectively controlled. An embodiment is also provided for selectively controlling the position of the moving element based upon measured electric and magnetic parameters of the actuator.

Abstract: A controlled force variable reluctance actuator. A variable reluctance actuator having a moving element operated by a solenoid is provided in which the current in the solenoid is controlled by a signal representative of the flux density in the magnetic circuit of the actuator. The signal is produced by a Hall effect device placed in the magnetic circuit. Preferably, the Hall effect device controls the current in the solenoid by controlling its duty cycle; however, continuous control of the current may also be employed. Alternative embodiments are provided for a constant force actuator, an actuator whose force-displacement characteristic is altered, and an actuator in which the force may be selectively controlled. An embodiment is also provided for selectively controlling the position of the moving element based upon measured electric and magnetic parameters of the actuator.

Abstract: A variable reluctance actuator, of either the linear or rotary type, having a moving element operated by a solenoid, is controlled by a Hall effect sensor signal representative of flux density in the magnetic circuit of the actuator. The actuator may be operated in either a constant-force control mode, or a position-sensing or control mode. Substantially constant force, independent of position of the actuator's movable element, is obtained by varying, rather than stabilizing, the sensed magnetic field during movement. Position sensing, independent of actuator force, is obtained by variably controlling the magnitude of the excitation current of the Hall effect sensor in response to the magnitude of the coil current and Hall sensor output.

Abstract: A permanent magnet motor having a highly nonuniform reluctance gap between rotor and stator creating reluctance torque which aligns the rotor in narrowly-defined detent zones when the motor coils are de-energized. To overcome the high reluctance torque present at the detent zones upon energizing of the coils, small auxiliary coils are provided adjacent the high reluctance regions of the gap to give the rotor a high immediate starting torque to escape the detent zones and rapidly achieve steady-state angular velocity.

Abstract: A stator assembly for a brushless DC permanent magnet motor or generator features an internal stator with electrical windings surrounded by a permanent magnet rotor. The stator assembly includes a collar member matingly interconnecting the stator core and the winding's power supply circuit board so as to automatically position them, during manufacture of the device, in predetermined angular and axial relationships with respect to each other, and in predetermined axial relationships with respect to the rotor. The collar member also contains an axial passageway which facilitates handling of the stator assembly during manufacture.