Method and apparatus for testing surface breakdown of dielectric materials caused by electrical tracking
AssigneeUnderwriters Laboratories Inc.
InventorJeffrey B. Hall
Life of this patent
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Abstract
An apparatus for testing a dielectric sample for susceptibility to surface electrical failure due to tracking. The apparatus includes an enclosure continuously purged of air-borne contaminants, which eliminates external drafts, and a base disposed within the enclosure for supporting the dielectric sample. A pair of electrodes are operably interconnected with a variable voltage power supply and adapted to engage the dielectric sample on a first side with a mutual separation. A source of water and water borne contaminants intermittently discharges the water and water-borne contaminants in droplet form onto the dielectric test sample between the electrodes.
Claims26
Apparatus for testing a dielectric sample for susceptibility to surface electrical failure due to tracking, such apparatus comprising:
- an enclosure adapted to be continuously purged of air-borne contaminants;
- a base disposed within the enclosure for supporting a dielectric sample;
- a pair of mutually separated electrodes operably interconnected with a variable voltage power supply and engaging the dielectric sample on a first side;
- a source of water and water borne contaminants adapted to intermittently discharge the water and water-borne contaminants onto the dielectric sample between the electrodes.
Apparatus for testing a dielectric sample for susceptibility to surface electrical failure due to tracking, such apparatus comprising:
- a base for supporting the dielectric sample;
- a pair of mutually separated electrodes restrained by a pair of vertically floating mounting brackets, operably interconnected with a variable voltage power supply and engaging the dielectric sample on a first side;
- a source of an electrolyte adapted to intermittently discharge the electrolyte onto the dielectric sample between the electrodes.
A method for testing a dielectric sample for susceptibility to surface electrical failure due to tracking within an enclosure adapted to be continuously purged of air-borne contaminants and eliminating external drafts having a base disposed within the enclosure for supporting the dielectric sample;
- a pair of vertically floating mutually separated electrodes operably interconnected with a variable voltage power supply and engaging the dielectric sample on a first side;
- and a source of electrolyte adapted to intermittently discharge the electrolyte onto the dielectric sample between the electrodes, comprising the steps of:
- purging the enclosure of air-borne contaminants eliminating external drafts;
- engaging the dielectric sample with the pair of electrodes;
- applying a voltage across the pair of electrodes;
- intermittently depositing the electrolyte onto the sample between the electrodes;
- measuring a true RMS voltage across the electrodes and true RMS current which flows through the electrodes for at least two seconds.
Dependencies are inferred from the claim text.