Underwater electrical power leakage current detector

• US 3,869,668 A
• Filed: 10/25/1973
• Issued: 03/04/1975
• Est. Priority Date: 10/25/1973
• Status: Expired due to Term

• Current Assignee: John R. Thompson
• Original Assignee: John R. Thompson
• Inventors: Thompson, John R.
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US05/410,010
• Time in Patent Office: 495 Days
• Field of Search: 324/51,72,54,72.5,133 317/18D 340/255
• US Class Current: 324/133
• CPC Class Codes: G01R 19/14 Indicating direction of current; Indicating polarity of voltage
• CPC Class Codes: G01R 19/15 Indicating the presence of current
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults

Abstract

An underwater electrical power-leakage detector comprising a metallic probe for sensing electrical currents. A resistor converts the current from the probe into a voltage which drives a positive and a negative voltage detector. The output of the positive and negative detectors drives a power trip relay or an indicator device. The electrical power-leakage detector is housed in a water-tight case.

Claims

1. An underwater diver protection device for detecting electrical-power leakage currents as small as two-tenths of a microampere from an underwater power source and tool comprising:

a water-tight, oil-filled, pressure-compensated case;

means for detecting positive voltages, located inside said case, having a sensor input and an output;

means for detecting negative voltages, located inside said case, having a sensor input and an output;

means for sensing electrical leakage currents as small as twotenths of a microampeRe in an underwater environment, said means extending out through said case and forming a water-tight seal at all points of penetration of said case, said means also having an output terminal located inside said case, said output terminal being connected to the sensor input of said means for detecting positive voltages and to the sensor input of said means for detecting negative voltages;

means connected between said output terminal of said means for sensing electrical currents and the power source for creating a voltage that is a function of the current sensed by said means for sensing electrical currents, thereby providing a voltage input to said means for detecting positive voltages and said means for detecting negative voltages whereby said means for detecting positive voltages and said means for detecting negative voltages output a trip signal when said leakage currents are sensed.

2. The underwater diver protection device of claim 1 wherein said means for sensing electrical currents comprises a metallic probe.

3. The underwater diver protection device of claim 1 wherein said means for creating a voltage comprises a resistive circuit.

4. An underwater electrical-power leakage detector for protecting divers from electrical shock comprising:

a water-tight, oil-filled, pressure-compensated case;

means for detecting positive voltages, located inside said case, having a sensor input and an output;

means for detecting negative voltages, located inside said case, having a sensor input and an output;

means for sensing electrical currents as small as two-tenths of a microampere in an underwater environment, said means extending through said case and having a first and second output terminal located inside said case, said means forming a water-tight seal at all points of penetration of said case, said first output terminal being connected to said sensor input of said means for detecting positive voltages, said second output terminal being connected to said sensor input of said means for detecting negative voltages; and

means connected between said first output terminal and said second output terminal for creating a voltage that is a function of the current sensed by said means for sensing electrical currents, thereby providing a voltage input to said means for detecting positive voltages and said means for detecting negative voltages whereby said means for detecting positive voltages and said means for detecting negative voltages output an indicator signal when said leakage currents are sensed.

5. The underwater electrical power leakage detector for protecting divers from electrical shock of claim 4 wherein said means for sensing electrical currents comprises:

an elongated electrically insulating rod having a first and a second end;

a first metallic rod partially embedded in said first end of said elongated rod;

a second metallic rod partially embedded in said second end of said elongated rod;

means for transmitting electrical currents from said first metallic rod to said first output of said means for sensing electrical currents; and

means for transmitting electrical currents from said second metallic rod to said second output of said means for sensing electrical currents.

6. The underwater electrical-power leakage detector for protecting divers from electrical shock of claim 4 wherein said means for creating a voltage comprises a resistive circuit.