Method and apparatus for testing the insulating ability of an insulation on an electric conductor

An apparatus for touch-free testing of electrical insulation of an insulated electrical conductor comprising:

• an array of testing electrodes having a passage through which the insulated electrical conductor passes during testing of the electrical insulation with at least one pair of spaced apart testing electrodes which are separated by a solid insulator extending along at least one of the at least one pair of spaced apart testing electrodes and the electrical conductor in a zone of testing which prevents puncture and sparking between the at least one pair of testing electrodes during testing of the electrical insulation of the electrical conductor;
• a corona generator, coupled to the array of testing electrodes, which produces corona that continuously contacts the insulated electrical conductor when the insulated electrical conductor is located in the passage;
• a voltage generator which applies a voltage between a reference potential and the array of testing electrodes;
• and
• a current measuring device, coupled to the insulated electrical conductor, which measures current flow through the insulation and the corona caused by any defect in the insulation to indicate the presence of the defects.