US4495448A — Means and method of sensing motor rotation speed …

Claim 1

Independent Claim 97 words

The method of deriving an electrical signal varying in characteristic as a function of the operational characteristics of a motor with electromagnetic stator and rotor windings comprising the steps of, operating the motor under rated conditions from a specified line power source, picking up signals from the stray magnetic flux field escaping from the motor stator and rotor interaction without requiring motor modifications for the purpose of providing a signal by placing an electromagnetic sensor responsive to the escaping magnetic flux within said field to sense the flux without any conductive or mechanical connections to the motor,

Claim 2

Independent Claim 97 words

The method of deriving an electrical signal varying in characteristic as a function of the operational characteristics of a motor with electromagnetic stator and rotor windings comprising the steps of, operating the motor under rated conditions from a specified line power source, picking up signals from the stray magnetic flux field escaping from the motor stator and rotor interaction without requiring motor modifications for the purpose of providing a signal by placing an electromagnetic sensor responsive to the escaping magnetic flux within said field to sense the flux without any conductive or mechanical connections to the motor,

Claim 3

Dependent Claim 27 words

and processing the signals derived from the escaping magnetic flux by said sensor to derive from that flux information representative of the rotational speed of the motor.

Claim 4

Dependent Claim 27 words

and processing the signals derived from the escaping magnetic flux by said sensor to derive from that flux information representative of the rotational speed of the motor.

Claim 5

Dependent Claim 29 words

The method of claim 1 including the step of producing from said signals derived from the flux an analog signal representative of the dynamic slip characteristics of the motor.

Claim 6

Dependent Claim 27 words

The method of claim 1 including the step of producing from said signals derived from the flux a digital representation of instantaneous slip characteristics of the motor.

Claim 7

Dependent Claim 51 words

The method of claim 1 including the step of fortifying the electromagnetic signals sensed by the sensor by amplifying the sensed signals deriving a frequency therefrom by band passing only those signals in the range of a motor speed harmonic and providing positive feedback of these amplified signals into the sensor.

Claim 8

Independent Claim 196 words

The method of deriving an electrical signal varying in characteristic as a function of the operational characteristics of a motor with electromagnetic stator and rotor windings comprising the steps of, operating the motor under rated conditions from a specified line power source, picking up signals from the stray magnetic flux excaping from the motor without requiring motor modifications for the purpose of providing a signal by placing an electromagnetic sensor responsive to the escaping magnetic flux within said field to sense the flux without any conductive or mechanical connections to the motor, processing and signals derived from the escaping magnetic flux by said sensor to produce information representative of the rotational speed of the motor, fortifying the electromagnetic signals sensed by the sensor by amplifying the signals and providing positive feedback of the amplified signals into the sensor, relatively positioning a plurality of windings in the sensor, providing one of the windings of a smaller diameter compared with larger diameters of the other windings, coaxially positioning the windings of larger diameter, offsetting the smaller diameter winding to a position adjacent a circumferential portion of the larger windings, and providing said positive feedback into the offset winding.

Claim 9

Independent Claim 196 words

The method of deriving an electrical signal varying in characteristic as a function of the operational characteristics of a motor with electromagnetic stator and rotor windings comprising the steps of, operating the motor under rated conditions from a specified line power source, picking up signals from the stray magnetic flux excaping from the motor without requiring motor modifications for the purpose of providing a signal by placing an electromagnetic sensor responsive to the escaping magnetic flux within said field to sense the flux without any conductive or mechanical connections to the motor, processing and signals derived from the escaping magnetic flux by said sensor to produce information representative of the rotational speed of the motor, fortifying the electromagnetic signals sensed by the sensor by amplifying the signals and providing positive feedback of the amplified signals into the sensor, relatively positioning a plurality of windings in the sensor, providing one of the windings of a smaller diameter compared with larger diameters of the other windings, coaxially positioning the windings of larger diameter, offsetting the smaller diameter winding to a position adjacent a circumferential portion of the larger windings, and providing said positive feedback into the offset winding.

Claim 10

Dependent Claim 26 words

The method of claim 5 including the step of positioning the axis of said coaxially positioned windings substantially parallel to the axis of the motor armature.

Claim 11

Independent Claim 162 words

The method of deriving an electrical signal varying in characteristic as a function of the operational characteristics of a motor with electromagnetic stator and rotor windings comprising the steps of, operating the motor under rated conditions from a specified line power source, picking up signals from the stray magnetic flux escaping from the motor without requiring motor modifications for the purpose of providing a signal by placing an electromagnetic sensor responsive to the escaping magnetic flux within said field to sense the flux without any conductive or mechanical connections to the motor, processing the signals derived from the escaping magnetic flux by said sensor to produce information representative of the rotational speed of the motor, fortifying the electromagnetic signals sensed by the sensor by amplifying the signals and providing positive feedback of the amplified signals into the sensor, and providing the positive feedback through a circuit tuned to a signal frequency harmonically related to the normal rotation speed of the induction motor.

Claim 12

Independent Claim 162 words

The method of deriving an electrical signal varying in characteristic as a function of the operational characteristics of a motor with electromagnetic stator and rotor windings comprising the steps of, operating the motor under rated conditions from a specified line power source, picking up signals from the stray magnetic flux escaping from the motor without requiring motor modifications for the purpose of providing a signal by placing an electromagnetic sensor responsive to the escaping magnetic flux within said field to sense the flux without any conductive or mechanical connections to the motor, processing the signals derived from the escaping magnetic flux by said sensor to produce information representative of the rotational speed of the motor, fortifying the electromagnetic signals sensed by the sensor by amplifying the signals and providing positive feedback of the amplified signals into the sensor, and providing the positive feedback through a circuit tuned to a signal frequency harmonically related to the normal rotation speed of the induction motor.

Claim 13

Dependent Claim 25 words

The method of claim 1 including the step of positioning the sensor at a single sensing position in the escaping flux pattern of the motor.

Claim 14

Dependent Claim 28 words

The method of claim 1 including the step of producing from the flux field an a-c signal of a frequency derived from the rotation speed of the motor.

Claim 15

Dependent Claim 128 words

Instrumentation for providing electrical signals representative of the rotation speed of a motor with electromagnetic stator and rotor windings by pick-up of the magnetic flux escaping from the stator-rotor interaction when operated from a specified line power source without requiring any mechanical or electrical modifications to the motor, comprising in combination, an electromagnetic sensing probe for response to said escaping flux when positioned in the vicinity of the motor, at least one pick-up winding and one feedback winding on said probe, and electronic means for amplifying signals sensed by said probe from the escaping flux of the motor and providing positive feedback signals to said feedback winding, thereby to produce a significant signal to noise improvement of the signal components representative of the rotation speed of the motor.

Claim 16

Dependent Claim 128 words

Instrumentation for providing electrical signals representative of the rotation speed of a motor with electromagnetic stator and rotor windings by pick-up of the magnetic flux escaping from the stator-rotor interaction when operated from a specified line power source without requiring any mechanical or electrical modifications to the motor, comprising in combination, an electromagnetic sensing probe for response to said escaping flux when positioned in the vicinity of the motor, at least one pick-up winding and one feedback winding on said probe, and electronic means for amplifying signals sensed by said probe from the escaping flux of the motor and providing positive feedback signals to said feedback winding, thereby to produce a significant signal to noise improvement of the signal components representative of the rotation speed of the motor.

Claim 17

Dependent Claim 53 words

Instrumentation as defined in claim 10 wherein the electronic means providing the feedback signals provides feedback by way of a tuned circuit resonant to a frequency band about a harmonic of the operational rotation frequency of the motor armature thereby to produce a fortified sensed signal representative of the rotation of the motor.

Claim 18

Dependent Claim 41 words

Instrumentation as defined in claim 10 wherein the tuned circuit is resonant at a harmonic of a frequency induced in the sensor by the armature poles of the motor as they rotate and provide escaping flux sensed by the pick-up winding.

Claim 19

Dependent Claim 35 words

Instrumentation as defined in claim 10 including means for further processing the signals derived from the probe and means for amplifying the signals to derive a signal representative of the slip characteristics of the motor.

Claim 20

Dependent Claim 28 words

Instrumentation as defined in claim 10 wherein the windings are located with an axis substantially parallel to the axis of rotation of the rotating element of the motor.

Claim 21

Dependent Claim 55 words

Instrumentation as defined in claim 10 wherein the sensing probe comprises at least one electromagnetic pick-up winding having a circumference of a predetermined diameter oriented about a winding axis, and a feedback winding of a smaller diameter positioned eccentrically within the pick-up winding with a feedback winding portion adjacent the circumference of the pick-up winding.

Claim 22

Dependent Claim 106 words

Instrumentation for providing electrical signals representative of the rotation speed of a motor with electromagnetic stator and rotor windings operated from a specified line power source by pick-up of the magnetic flux escaping from the rotor-stator interaction without requiring any mechanical or electrical modifications to the motor, comprising in combination, an electromagnetic sensing probe for deriving signals from said escaping flux when positioned adjacent a motor, and electronic circuit means for processing the sensed flux signals to produce therefrom a signal representative of the rotation speed of the motor, For the two added independent claims the fee is paid by the enclosed deposit account order form.

Claim 23

Dependent Claim 40 words

Instrumentation as defined in claim 16 wherein the electronic sensing probe contains electromagnetic windings with an axis adapted to derive signals for processing by said circuit means when oriented substantially parallel to the axis of rotation of the motor rotor.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-01-22	1988-07-23	1989-01-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-01-22	1992-07-23	1993-01-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-01-22	1996-07-23	1997-01-22	$7700.00	Window Closed / Lapsed

Means and method of sensing motor rotation speed from stray escaping flux

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