Voltech AT360, User Manual

Page: 375 / 470

V
OLTECH
AT
I
U
SER
M
ANUAL
P
AGE
7-77
7.1.18 IR – I
NSULATION
R
ESISTANCE
Test Measurement
Range
Test
Voltage
Test
Frequency
Basic
Accuracy
IR 1M
Ω
to 1G
Ω
100V to 500V DC 1.0%
Transformer windings are often insulated from each other and from the
core by insulating tape, enamel on the wire or by plastic moulding on the
bobbin.
The 'quality' of the insulation can be assessed by applying a DC voltage
across the insulation and measuring the resistance. The voltage applied
is usually greater than the voltage that the insulation will see in normal
use.
Where Used
An Insulation Resistance check is recommended as good practice for most
transformers to check the integrity of the insulation between separate
windings, or between a windings, or between a winding and a screen.
Test Conditions