Associated Research 7700, Operation And Service Manual

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operating voltage, plus 1,000 volts.
However, specific products may be tested at much higher voltages than 2X operating voltages
+ 1,000 volts. For example, a product designed to operate in the range between 100 to 240
volts can be tested between 1,000 to 4,000 volts or higher. Most "double insulated" products
are tested at voltages much higher than the "rule of thumb".
Testing during development and prototype stages is more stringent than production run tests
because the basic design of the product is being evaluated. Design tests usually are performed
on only a few samples of the product. Production tests are performed on every item as it
comes off the production line.
The hipot tester must also maintain an output voltage between 100% and 120% of
specification. The output voltage of the hipot must have a sinusoidal waveform with a
frequency between 40 to 70 Hz and has a peak waveform value that is not less than 1.3 and not
more than 1.5 times the root-mean-square value.
Types of Failures only detectable with a Hipot test

Weak Insulating Materials

Pinholes in Insulation

Inadequate Spacing of Components

Pinched Insulation
Dielectric Withstand Test; AC verses DC
Please check with the Compliance Agency you are working with to see which of the two types
of voltages you are authorized to use. In some cases, a Compliance Agency will allow either
AC or DC testing to be done. However, in other cases the Compliance Agency only allows for
an AC test. If you are unsure which specification you must comply with please contact our
CUSTOMER SUPPORT GROUP at 1-800-858-TEST (8378).
Many safety agency specifications allow either AC or DC voltages to be used during the hipot
test. When this is the case, the manufacturer must make the decision on which type of voltage
to utilize. In order to do this it is important to understand the advantages and the disadvantages
of both AC and DC testing.
AC testing characteristics
Most items that are hipot tested have some amount of distributed capacitance. An AC voltage
cannot charge this capacitance so it continually reads the reactive current that flows when AC
is applied to a capacitive load.