Electrical measurements. Problem 30

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Problem №30. Electrical measurements.

The insulation resistance between the two wires overhead line was measured by a voltmeter designed for a rated voltage of 150V and rated current 0,75mA. The wires at the opposite end of the line was open. Voltmeter readings when measuring the voltage between the wires was 110 V, and when the voltmeter in series with one of the wires of his testimony was 40B. Draw a diagram of the insulation resistance measurement. Define:
- The resistance of the voltmeter;
- The insulation resistance between the conductors.
Specify which devices are used for direct measurement of insulation resistance of electrical installations.