Brushless tachometer/synchro

Abstract

A generator providing both tachometer and synchro outputs and comprising a magnetic stator and a corresponding armature structure. The generator stator structure produces a composite magnetic field of both constant (DC) and alternating (AC) flux. The rotor directs the composite flux field through a plurality of sensing coils, each producing a signal from the sensed composite magnetic field and rotor motion, and which coil signal is separated into separate signal components. The components are processed to produce a synchro output which preferrably has standard Hall-effect equivalent signals, as well as providing a tachometer output voltage proportional to the rotor rotational velocity and direction.

What is claimed is: 
     
       1. A generator, comprising: means for providing a magnetic field including a constant field and an alternating field having a frequency of alternation;   means for detecting said magnetic field producing a corresponding detected field signal;   an armature for selectively coupling said .Iadd.magnetic .Iaddend.field according to a physical motion of said armature through a range; and   output means receiving said detectede field signal and producing a tachometer output and a position ouptut therefrom.   
     
     
       2. The generator of claim 1, wherein said means for providing a magnetic field includes an oscillator for exciting said means for providing a magnetic field at said frequency of alternation; and   said .[.magnetic.]. .Iadd.detected .Iaddend.field signal includes .Iadd.detected .Iaddend.AC and DC .Iadd.field .Iaddend.signals corresponding to the constant and said alternating field and the movement of said armature therethrough.   
     
     
       3. The generator of claim 2, wherein said output means includes   a phase-sensitive detector receiving said oscillator signal and said detected AC field signals and providing said position output.   
     
     
       4. The generator of claim 3, wherein said position ouptut is a standard Hall-effect equivalent output.   
     
     
       5. The generator of claim 3, wherein said phase-sensitive detector further produces a commutation signal according to the position of said armature relative to said means for providing a magnetic field; and   said output means further includes switch means receiving said detected DC field signals and said commutation signal and producing said tachometer output signal.   
     
     
       6. The generator of claim 5, wherein said detected field signal comprises a plurality of signals in phase spacing, wherein   through said range, the amplitude of at least one of said .[.three signals.]. .Iadd.plurality of signals in phase spacing .Iaddend.corresponds to the armature motion.   
     
     
       7. The generator of claim 6, wherein said phase spacing are equal phase spacings. 
     
     
       8. The generator of claim 6, wherein said plurality of .[.detected field.]. signals .Iadd.in phase spacing .Iaddend.comprises three signals to provide a three-phase generator. 
     
     
       9. The generator of claim 8, wherein said detected DC field signals from said three signals .[.from.]. .Iadd.form .Iaddend.a contiguous signal being directly proportional to the velocity of said armature motion throughout the range of armature motion; and   said switch means selectively combines said three signals to form said tachometer output signal. .Iadd.   
     
     
       10.  The generator of claim 1 wherein said output means further includes (i) means for producing a commutation signal according to the position of said armature relative to said means for providing a magnetic field and (ii) switch means receiving a component of said detected field signal and said commutation signal and producing said tachometer output signal. .Iaddend. .Iadd.11. The generator of claim 1 wherein said output means further includes means to separate said detected field signal into a DC signal correlated to said constant field and an AC signal correlated to said alternating field; commutating means receiving said AC signal and generating said position output signal;   switch means receiving said position output signal and said DC signal to produce said tachometer output signal. .Iaddend. .Iadd.12. A generator comprising   a stator;   means for providing a magnetic field associated with said stator including a constant field and an alternating field having a frequency of alternation;   a brushless rotor movable within said stator to selectively couple said constant field and said alternating field and generate a composite field signal;   pickup means associated with said stator to detect said composite field signal;   means to separate said composite field signal into a first and second field signal; and   output means including commutator means timed by said frequency of alternation and receiving said first field signal to generate a first output signal correlated to the position of said rotor within said stator.   
     
     
        .Iaddend. .Iadd.13.  The generator of claim 12 wherein said first field signal is correlated to said alternating field, said second field signal is correlated to said constant field, said output means further including switch means receiving said second field signal and said first output signal to generate a second output signal, said second output signal correlated to the velocity of said rotor within said stator. .Iaddend.