DIELECTRIC VOLTAGE-WITHSTAND TEST -
Dielectric voltage-withstand Test (High Voltage Test)
is carried out by applying a significantly higher than operating voltage to the
device under test. The Dielectric Withstand Test (also known as hipot test) consists
in measuring the current leak of a device under test, while phase and neutral are
short-circuited together. The measure result of a Dielectric Withstand Test is a
current value, which has to be lower than the indicated limit from the international
standards. In this test, the insulation of a product, stressed to a greater extent
than normal operating conditions, should not breakdown for the product to pass this
test. During type testing, i.e. testing during designing a product or for double-insulated
product, however, much larger voltage may be applied for performing high voltage
test.
For all electrical products, high voltage test is a
100% routine test, i.e – every unit should pass high voltage test before it can
be shipped.
Dielectric voltage-withstand Test is performed in AC
or DC with voltages varying from some hundred volts to several tens of kilovolts.
The choice of the nature and value of the test voltage is determined by standards,
which apply to the product tested.
In the absence of standards, the following rule of
thumb is used - the test is always performed with a voltage of same nature than
that under which the sample operates.
|