Rls Or Rlp - Equivalent Series Or Parallel Resistance - Voltech AT5600 User Manual

C H A P T E R 7 – T E S T S
7.6. RLS or RLP - Equivalent Series or Parallel
Resistance
Where Used
The equivalent series or parallel resistance measurements are alternatives to a Q
factor measurement to follow the inductance test in the program.
As with the Q factor measurement, an equivalent series or parallel resistance 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.
An equivalent resistance test is also one way of highlighting shorted turns within
the transformer.
Measurement Conditions
As with measuring inductance and Q factor, to measure an equivalent series or
parallel resistance, the tester applies an AC voltage across the selected winding.
It then measures the voltage across and current through the winding using
harmonic analysis. The measured voltage is divided by the current to obtain the
complex impedance and the equivalent series or parallel resistance calculated.
If, in the program, the RLS or RLP test follows either a LS or LP test which has
the same test conditions (voltage and frequency), and is applied to the same
winding, then the measurement results from the previous inductance test can be
re-used, saving program execution time.
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 RLS or RLP test. If the RLS or RLP 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
14.6.3 for specific advice on programming the test, and
10.2.2 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
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