Abstract: An annular guard (20) for mounting on a high voltage insulator extends laterally thereof for a sufficient distance so as to prevent small wildlife such as squirrels from forming a short circuit between the opposing ends of the insulator at high voltage and earth potential respectively. The guard (20) is formed in two planar parts (24, 26) that are pivoted together (28) so that they can be relatively rotated between an open condition for mounting onto a live insulator and a closed condition for being secured thereto. Overlapping regions of the two parts are secured together (30, 32, 34, 36, 38) in the closed condition.

Abstract: The invention relates to a shield which prevents squirrels or other animals from causing faults in power distribution substations. Switch and bus insulators are primary points of contact when a small animal crawls from a grounded, supporting structure across an insulator to an energized conductor. The present invention provides for a barrier on switch and bus insulators which prevents animals from coming into contact with a grounded structure and an energized conductor simultaneously, thus eliminating a ground path from the energized conductor through the animal to the grounded structure.

Abstract: The invention relates to a shield which prevents squirrels or other animals from causing faults in power distribution substations. Switch and bus insulators are primary points of contact when a small animal crawls from a grounded, supporting structure across an insulator to an energized conductor. The present invention provides for a barrier on switch and bus insulators which prevents animals from coming into contact with a grounded structure and an energized conductor simultaneously, thus eliminating a ground path from the energized conductor through the animal to the grounded structure.

Abstract: A method for determining whether a metallic path (such as a wire) under test carrying an undetermined load current is so corroded as to require replacement applies a test current to the metallic path under test and a total current passing through the metallic path, equal to the sum of the undetermined load current and the test current, is measured. A voltage between two selected points, separated by a known length, on the metallic path is also measured. Resistance of the metallic path is then calculated by measuring an angular phase difference between the voltage and the total current, calculating an impedance of the metallic path from the values of the voltage and the total current then multiplying the impedance by the cosine of the angular phase difference. The resistance of the metallic path under test is correlated to the resistance of metallic paths of known corrosion to determine the degree of corrosion on the metallic path under test.

Abstract: The present invention is a transformer alarm annunciator which discloses a system that transmits a general alarm signal to a central location in response to one of a plurality of alarm conditions without blocking the signal path, so that in the event of system failure the alarm signal will still be transmitted as a transformer alarm. The device provides a means to disable a particular alarm condition while allowing the remaining alarms to be monitored.