Voltech ATi User Manual page 375

7.1.18 IR – I
NSULATION
Test
IR
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
V AT U
OLTECH I SER
R
ESISTANCE
Measurement
Range
1MΩ to 1GΩ
M
ANUAL
Test
Voltage
100V to 500V
Test
Frequency
DC
Basic
Accuracy
1.0%
P 7-77
AGE