Electrical conductor and short circuit locator

Claim 1

An apparatus for locating electrical conductors and short circuits comprising: first and second test leads for connecting across open circuit breaker means in a circuit to be tested; the open circuit breaker means having a voltage potential across its terminals due to a circuit power source; current limiting means connected across the test leads for allowing current due to the circuit power source to flow through the current limiting means and the circuit, and for limiting the current in the circuit being tested to a predetermined value to prevent excessive short circuit current in the circuit being tested; the predetermined value being sufficiently high such that pulsated and alternated currents are discernable at conducting points in the circuit by a clamp-on ammeter; first pulse generating means, cooperating with the current limiting means, for intermittently interrupting the current in the circuit being tested; the first pulse generating means providing an on duration of the current in the circuit being tested sufficient for a clamp-on ammeter in an AC circuit to indicate a momentary pulse with the off duration substantially greater than the on duration; and second pulse generating means, cooperating with the current limiting means and connected in series with the first pulse generating means, for interrupting the momentary pulse created by the first pulse generating means to provide a pulsating component in the momentary pulse so that a current reading is visible on a clamp-on ammeter in a DC circuit at all points along the circuit except at the short circuit.

Claim 2

An apparatus for locating electrical conductors and short circuits comprising: first and second test leads for connecting across open circuit breaker means in a circuit to be tested; the open circuit breaker means having a voltage potential across its terminals due to a circuit power source; current limiting means connected across the test leads for allowing current due to the circuit power source to flow through the current limiting means and the circuit, and for limiting the current in the circuit being tested to a predetermined value to prevent excessive short circuit current in the circuit being tested; the predetermined value being sufficiently high such that pulsated and alternated currents are discernable at conducting points in the circuit by a clamp-on ammeter; first pulse generating means, cooperating with the current limiting means, for intermittently interrupting the current in the circuit being tested; the first pulse generating means providing an on duration of the current in the circuit being tested sufficient for a clamp-on ammeter in an AC circuit to indicate a momentary pulse with the off duration substantially greater than the on duration; and second pulse generating means, cooperating with the current limiting means and connected in series with the first pulse generating means, for interrupting the momentary pulse created by the first pulse generating means to provide a pulsating component in the momentary pulse so that a current reading is visible on a clamp-on ammeter in a DC circuit at all points along the circuit except at the short circuit.

Claim 7

An apparatus for locating electrical conductors and short circuits, comprising: power supply means for providing a DC voltage; first pulse generating means connected to the power supply means for generating a momentary pulse of substantially 1/2 to 1 second duration substantially every 3 to 5 seconds; second pulse generating means connected in series with the first pulse generating means for pulsating the momentary pulse at a frequency in the range from 100 to 500 cycles per second; first and second test leads for connecting across open circuit breaker means in a circuit to be tested; the open circuit breaker means having a voltage potential across its terminals due to a circuit power source; current limiting means connected across the test leads for allowing current in the circuit due to the circuit power source to flow through the current limiting means and the circuit, and for limiting the current in the circuit being tested to a pulsating and alternating value substantially in the range from 0.25 to 5.0 amps; switch means connected with the current limiting means for switching on and off the current flow; and optical isolator means, including a light emitting diode and a photosensitive transistor, for actuating the switch means responsive to the pulsating output from the second pulse generator means, thereby causing an intermittent current pulse in the circuit being tested for detection by a clamp-on ammeter.

Claim 8

An apparatus for locating electrical conductors and short circuits, comprising: power supply means for providing a DC voltage; first pulse generating means connected to the power supply means for generating a momentary pulse of substantially 1/2 to 1 second duration substantially every 3 to 5 seconds; second pulse generating means connected in series with the first pulse generating means for pulsating the momentary pulse at a frequency in the range from 100 to 500 cycles per second; first and second test leads for connecting across open circuit breaker means in a circuit to be tested; the open circuit breaker means having a voltage potential across its terminals due to a circuit power source; current limiting means connected across the test leads for allowing current in the circuit due to the circuit power source to flow through the current limiting means and the circuit, and for limiting the current in the circuit being tested to a pulsating and alternating value substantially in the range from 0.25 to 5.0 amps; switch means connected with the current limiting means for switching on and off the current flow; and optical isolator means, including a light emitting diode and a photosensitive transistor, for actuating the switch means responsive to the pulsating output from the second pulse generator means, thereby causing an intermittent current pulse in the circuit being tested for detection by a clamp-on ammeter.

Claim 10

An apparatus for locating electrical conductors and short circuits, comprising: power supply means for providing a DC voltage; first pulse generating means connected to the power supply means for generating a momentary pulse with an on duration sufficient for a clamp-on ammeter in an AC circuit to indicate a momentary pulse, with the off duration considerably greater than the on duration; second pulse generating means connected in series with the first pulse generating means for pulsating the momentary pulse at a frequency sufficiently high so that a current reading is visible on a clamp-on ammeter in a DC circuit; first and second test leads for connecting across open circuit breaker means in a circuit to be tested; the open circuit breaker means having a voltage potential across its terminals due to a circuit power source; current limiting means connected across the test leads for allowing current in the circuit due to the circuit power source to flow through the current limiting means and the circuit, and for limiting the current in the circuit being tested to a predetermined value to prevent excessive short circuit current; the predetermined value being sufficiently high such that pulsated and alternated currents are discernable at conducting points in the circuit by a clamp-on ammeter; switch means connected with the current limiting means for switching on and off the current flow; and optical isolator means, including a light emitting diode and a photosensitive transistor, for actuating the switch means responsive to the pulsating output from the second pulse generator means, thereby causing an intermittent current pulse in the circuit being tested for detection by a clamp-on ammeter.

Claim 11

An apparatus for locating electrical conductors and short circuits, comprising: power supply means for providing a DC voltage; first pulse generating means connected to the power supply means for generating a momentary pulse with an on duration sufficient for a clamp-on ammeter in an AC circuit to indicate a momentary pulse, with the off duration considerably greater than the on duration; second pulse generating means connected in series with the first pulse generating means for pulsating the momentary pulse at a frequency sufficiently high so that a current reading is visible on a clamp-on ammeter in a DC circuit; first and second test leads for connecting across open circuit breaker means in a circuit to be tested; the open circuit breaker means having a voltage potential across its terminals due to a circuit power source; current limiting means connected across the test leads for allowing current in the circuit due to the circuit power source to flow through the current limiting means and the circuit, and for limiting the current in the circuit being tested to a predetermined value to prevent excessive short circuit current; the predetermined value being sufficiently high such that pulsated and alternated currents are discernable at conducting points in the circuit by a clamp-on ammeter; switch means connected with the current limiting means for switching on and off the current flow; and optical isolator means, including a light emitting diode and a photosensitive transistor, for actuating the switch means responsive to the pulsating output from the second pulse generator means, thereby causing an intermittent current pulse in the circuit being tested for detection by a clamp-on ammeter.