Lpbx - Inductance With External Bias (Parallel Circuit) - Voltech AT5600 User Manual

C H A P T E R 7 – T E S T S
7.42. LPBX – Inductance with External Bias (Parallel
Circuit)
DC Bias
0.1A to 250A
This test requires the use of one or more Voltech DC1000 Precision DC Bias
Current Sources.
IMPORTANT; When using this test, ensure that the terminal you pick as
HIGH in the editor program is also the node that is connected to the AHi
output of the DC1000. Similarly, the node you specify as LOW should also
be the node that is connected to the ALo output of the DC1000
The inductance of a transformer winding while an external bias current is flowing
through it may be tested using series or parallel equivalent circuit models.
Initially the DC bias current is set up and allowed to stabilize.
An AC voltage is applied across the selected winding; the voltage across and
current through the winding are then measured using harmonic analysis.
The measured voltage is divided by the current to obtain complex impedance and
the inductance is calculated.
IMPORTANT UPDATE FOR LEGACY AT3600 USERS
The DC1000 can be easily integrated with the AT series testers to give automated
and integrated DC Bias testing, combined with the wide range of tests provided by
the AT Series.
If you are integrating the DC1000 with any of the high voltage AT tests (IR, HPAC,
HPDC, DCRT, ACRT, DCVB & ACBV) it is important that the DC1000 is ONLY
connected to nodes used as the LO terminals in these high voltage tests. This will
prevent damage to the DC1000.
Any terminals used for LSBX, LPBX & ZBX, cannot be used as "HI" terminals for
IR HPAC, HPDC, DCRT, ACRT, DCVB or ACBV in the same program.
The AT5600 and AT Editor will check for this and warn you if you are attempting
to do this. The AT3600 and old AT Editor did not give this warning, but it is still a
valid best practice for the AT3600. See DC1000A user manual section 6.5.4
Please also see
14.6.38 for specific advice on programming the test, and
10.2.27 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
Measure Test
Range Voltage
1nH 1MH 1mV to 5V
Test
Basic Accuracy
Frequency
20Hz to 3MHz 0.2% @ Q>10
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