VOLTECH AT3600 USER MANUAL TRANSFORMER TESTS
TESTS AND TEST CONDITIONS VPN 98 - 024 PAGE 7.1.5.
1.3. R - WINDING RESISTANCE
WHERE USED
The measurement of the resistance of all windings should generally be the first group
of tests carried out for any type of transformer. It checks that the wire is of the
correct diameter, and has not been over-tensioned during winding.
The measurement also confirms that the connections between the test fixture and the
transformer have been made properly. This is particularly important when Kelvin
connections are required, perhaps for a test to follow, as a resistance measurement
will confirm that both the power lead and sense lead are making good electrical
contact.
To check that the resistance of a winding is correct, the tester applies a constant
current (dc) to the selected winding. Both the current through and the voltage across
the winding are measured; dividing the voltage by the current gives the value of the
resistance.
SPECIFYING THE TEST LIMITS
Maximum Value - Specify limit as tightly as possible to ensure that correct wire
has been used.
Minimum Value Not usually so critical - can be set to any value that ensures
that there is no solder splash causing a short circuit between
pins.
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