Ql - Quality Factor - Voltech AT5600 User Manual

C H A P T E R 7 – T E S T S
7.9.

QL - Quality Factor

Where Used
The Q factor measurement would normally follow a measurement of the
inductance of the primary winding in the test program.
As with an inductance measurement, the Q factor test would normally be used for
signal, pulse and switched mode power transformers, where the normal operating
conditions require only small excursions of the B-H curve, never extending
beyond the linear regions.
A Q factor test is one way of highlighting shorted turns within the transformer.
Measurement Conditions
To measure Q factor, the tester performs the same steps that would be used to
measure inductance. The only difference is in the calculation at the end of the
test: the measured voltage is divided by the current to obtain the complex
impedance from which the Q factor is calculated.
The test signal can have a frequency in the range 20Hz to 3MHz, and amplitude
from 1mV to 5V.
Normally when following an inductance test, you would choose the same test
conditions for the QL test. If the QL test does not have an associated inductance
test, then choose the test conditions as detailed in Section 7.7.2 Table 2, based
on the value of the inductance of the winding under test.
Please also see
14.6.6 for specific advice on programming the test, and
10.2.3 for test accuracy specification
AT5600 User Manual 98-119 issue 14
A N D T E S T C O N D I T I O N S
Page 105