A DC voltage is applied to conductive brushes.  The wire runs through the brushes.  A current will flow when there is a pinhole or weak spot in the insulation.  The DC voltage range is 0 – 3000 VDC.  The voltage is set from the computer.  The series resistance of the voltage source is 60,000,000 ohms. 

 

The bead detection part of the detector uses 2 spring loaded arms with ceramic guides to touch the moving wire.  When there is a bead the arm moves outward and a sensor detects the movement. There is one sensor in each arm.  The detector has a CPU and A/D.  The digital data from the detector is sent to the system console.

 

Wire Size Range 18 AWG to 1 AWG (1.0 mm to  7.0 mm)