The Dissipation Factor test (DF) & Capacitance test (C) of the instruments is a low
voltage method to measure the Dissipation Factor [also known as tan delta (loss
angle)] and the Capacitive system inside the motor formed by the motor frame and
the stator windings. Due to the inherently high impedance nature of the DF & C test
the instruments connection is designed to form a shielded test setup together with
the motor object under test.
All DF & Capacitance testing should be performed directly on the motor terminals as instructed and
pictured in this Manual.
Only the supplied (shielded) test leads and clips should be used. The use of any additional cable(s)
between the test clips and motor terminals can introduce hum and/or other interference that can
result in erratic readings for DF and C. In addition, longer cable lengths can also add the influence of
the cable itself.
In order to get the highest possible accuracy for the DF test, the instrument should be allowed to
have a warmup time of approximately 10 seconds after powering “ON” (this allows time for the DC
and offset levels to stabilize). Note that the specification for DF and Capacitance is based on battery
powered operation. The USB communication cable cannot be connected to a computer during the
DF (or Contamination) test described below.
Test Steps
Before starting this test, verify that you have a good ground. To do so, entering into "INS" menu,
connect the blue test lead and yellow lead to the instrument. Clip the connectors onto ground test
lead and motor frame ground. Press the button to do the insulation test. If it shows a value close to
0 Ω, it means the ground test lead is good. Otherwise, please check to make sure the ground test
lead is really grounded. The steps are described in the Section “Verifying Proper Ground
Connections”.
To start the static and dynamic tests, select the “IND” icon in the Main Menu and press the OK key.
DF/C Test
Connect the test leads according to instructions in the message screen.
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