Kyoritsu 6010B User Manual download pdf (Page 14)

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WARNING

ENSURE THAT CIRCUITS TO BE TESTED ARE NOT LIVE.

DISCONNECT THE INSTRUMENT FROM THE CIRCUIT UNDER TEST

BEFORE OPERATING THE FUNCTION SWITCH.

TO SELECT THE INSULATION RESISTANCE RANGE SELECT

“INSULATION”

6．1 The nature of insulation resistance

Live conductors are separated from each other and from earth metal by

insulation, which has a resistance which is high enough to ensure that the

current between conductors and to earth is kept at an acceptably low level.

Ideally insulation resistance is infinite and no current should be able to flow

through it. In practice, there will normally be a current between live conductors

and to earth, and this is known as leakage current. This current is made up of

three components, which are:-

1．capacitive current

2．conduction current, and

3．surface leakage current.

6．1．2 Capacitive Current

The insulation between conductors which have a potential difference between

them behaves as the dielectric of a capacitor, the conductors acting as the

capacitor plates. When a direct voltage is applied to the conductors, a charging

current will flow to the system which will die away to zero (usually in less than a

second) when the effective capacitor becomes charged. This charge must be

removed from the system at the end of the test, a function which is automatically

performed by KEW 6010B. If an alternating voltage is applied between the

conductors, the system continuously charges and discharges as the applied

voltage alternates, so that there is a continuous alternating leakage current

flowing to the system.

6. INSULATION TESTS

Fig 4

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Kyoritsu 6010B User Manual Page 14