Insulation resistance measurement circuit - for winding and iron core in electric machines uses scanner and oscillator

摘要

A rectangular voltage generator (1) is inserted between the tested object (6) and earth through a coupling element and a measurement resistor (2). Voltage drop across resistor (2) is applied to a controlled scanning device (8) which detects and stores the voltage at the end of each half-period of the oscillator (1) rectangular voltage. The stored voltages are applied to a subtractor (10) whose output voltage is a measure for the object insulation resistance.