DE-SYNCHRONIZING SYSTEM

• US 3,742,444 A
• Filed: 11/04/1970
• Issued: 06/26/1973
• Est. Priority Date: 11/04/1970
• Status: Expired due to Term

• Current Assignee: Baroid Technology Incorporated
• Original Assignee: James M. Lindsey
• Inventors: Lindsey, James M.
• Primary Examiner(s): Borchelt, Benjamin A.
• Assistant Examiner(s): Birmiel, H. A.
• Application Number:
  US05/086,915
• Time in Patent Office: 965 Days
• Field of Search: 318/74,112,310,341,85 307/240,252B 340/18R
• US Class Current: 340/853.3
• CPC Class Codes: E21B 47/022 of the borehole, e.g. using geomagnetism
• CPC Class Codes: E21B 47/12 Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling

Abstract

The particular embodiment described herein as illustrative of one form of the invention utilizes a circuit for desynchronizing a first synchronous motor. The motor drives a surface indicating apparatus which displays light signals in timed relation with the downhole detection of borehole parameters. Such downhole detection is accomplished with the use of a second synchronous motor driven from the same power supply as the first synchronous motor. Desynchronization of the first motor permits the display signals to be moved with respect to a scale, and thereby be more easily interpreted by an operator.

Claims

1. An apparatus for adjusting the phase of a synchronous electric motor including:

circuit means for supplying uniform current to the motor thereby providing non-varying motor phase;

an electronic switch device in said circuit means for controlling the motor phase by regulating the relationship between motor speed and current level; and

selectively operable automatic means for periodically shutting off said switching device for a precisely timed portion of the motors rotational cycle to thereby cease the passage of current to said synchronous motor, said electronic swithcing device being a solid state, gated, power device which is operated to pass current on the application of a voltage if a predetermined level to the gate of said power device, shutting off means including trigger means normally operable to pass said voltage of a predetermined level to said power device.

2. The apparatus of claim 1 wherein said shutting off means also includes means for periodically applying blocking voltage pulses of constant duration to said trigger means to cease the operation of said trigger means.

3. The apparatus of claim 2 wherein said blocking voltage applying means is an oscillator.

4. The apparatus of claim 3 and further including means for varying the output frequency of said oscillator.

5. The apparatus of claim 4 wherein said output varying means is a variable resistance means.

6. In an apparatus for operating in a borehole:

first synchronous motor means for performing a downhole operation;

second synchronous motor means for providing a surface indication of the downhole operation;

power supply means for operating both of said motors synchronously; and

selectively operable means for periodically ceasing the supply of power to one of said synchronous motors.

7. The apparatus of claim 6 wherein said selectively operable means includes switch means for passing power to said one of said synchronous motors and means for cyclically ceasing the operation of said switch means.

8. The apparatus of claim 7 wherein said switch means is a solid state bi-directional gated switch and further including a trigger for operating the gate of said switch and oscillator means for operating said trigger.

9. The apparatus of claim 8 wherein said oscillator means includes means for varying the output frequency of said oscillator.

10. In a borehole tool for detecting a downhole parameter and passing signals indicative of such detected parameter to the surface:

downhole means for detecting a parameter, said downhole means including a first synchronous motor for operating such detecting means;

surface means for providing a visual display of the detected parameter in time relation to its downhole detection;

a second synchronous motor for operating said surface means;

common power supply means for operating said first and second synchronous motors in time relation; and

means for intermittently ceasing the operation of said second synchronous motor.

11. The apparatus of claim 10 wherein said visual display means includes a light flash means for projecting a light flash onto a scale with said synchronizing motor moving said light flash means relative to said scale.

12. The apparatus of claim 10 wherein said ceasing means includes a gated bi-directional solid state switch for passing power to said second synchronous motor and selectively operable oscillator means for periodically opening said gated switch.