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US 5,136,234 AGranted
Digital high-voltage meter device
AssigneeHastings Fiber Glass Products, Inc.
InventorLewis A. Shaw
Life of this patent
Estimating the term…
Abstract
A digital, high-voltage meter device is comprised of two poles, each having a probe connected to high-voltage resistors. The resistors are connected to supply low-voltage inputs to a digital voltmeter. In a modification, one of the poles including its probe and high-voltage resistor, is replaced by a connector, such as an alligator clip, adapted to be releasably connected to system ground.
Claims17
A portable device, comprising:
- means for identifying the phases and for determining the approximate line-to-line or line-to-ground voltage of overhead or underground electrical utility power supplies, including:
- a pair of elongated, hollow poles made of electrical insulating material, each of said poles having a probe at one end thereof and containing high voltage resistor means connected to said probe and adapted to provide a low current output signal;
- a casing containing a circuit board providing a digital voltmeter and a battery for powering said voltmeter, said casing being mounted on one of said poles, said digital voltmeter having a pair of input terminals, one of said input terminals being connected to said resistor means in said one pole;
- a self-retracting, coiled, cable extending between said poles, said cable having a conductor, one end of which is connected to said resistor means in the other pole and the other end of which is connected to the other of said input terminals of said digital voltmeter whereby an A.C. signal is supplied to said digital voltmeter, said digital voltmeter comprising filter means for filtering out selected high frequency range and low frequency range of said signal, A.C. amplifier means for amplifying said signal, rectifier means for rectifying said signal, and a digital meter connected for receiving the rectified signal and providing a visible digital readout indicative of the voltage sensed by said probes.
1 more element
A portable device, comprising:
- means for determining the approximate line-to-ground voltage of underground electrical utility power supplies, including:
- an elongated, hollow pole made of electrical insulating material, said pole having a probe at one end thereof and containing high voltage resistor means connected to said probe and adapted to provide a low current output signal;
- a casing containing a digital voltmeter and a battery for powering said voltmeter, said casing being mounted on said pole, said digital voltmeter having a pair of input terminals, one of said input terminals being connected to said resistor means in said pole;
- a self-retracting, coiled, cable extending from said pole, said cable having a connector at the free end thereof for removable connection to a ground terminal, said cable having a conductor one end of which is connected to said connector and the other end of which is connected to the other of said input terminals of said digital voltmeter whereby an A.C. signal is supplied to said digital voltmeter, said digital voltmeter comprising filter means for filtering out selected high frequency range and low frequency range of said signals, A.C. amplifier means for amplifying said signal, rectifier means for rectifying said signal, and a digital meter connected for receiving the rectified signal and providing a visible digital readout indicative of the voltage sensed by said probes.
1 more element
A portable device for measuring a voltage difference between respective points on utility power lines, comprising:
- an elongate pole made of an insulating material, first and second probes each adapted for engagement with a utility power line, a digital voltmeter circuit having first and second input terminals and means electrically coupling each of said input terminals to a respective one of said probes, digital display means coupled to said voltmeter circuit for providing a visible digital display of a voltage difference between said probes, means defining an electrical shield disposed around said digital voltmeter circuit, said shield being electrically connected to one of said input terminals of said digital voltmeter circuit, and means supporting on said pole said digital voltmeter circuit, said digital display means and said means defining said shield.
Dependencies are inferred from the claim text.