26
Automatic GOOD/BAD Inductor Value Testing
The LC103 will automatically compare the measured
value of an inductor to its marked value and display a
good or bad result, based on the component being in or
out of tolerance. In order for the ReZolver to compare
the marked value to the measured value you must
program the inductance value and tolerance into the
LC103 using the NUMERIC keypad. Then when you
push the INDUCTOR VALUE button, the measured
inductance value will be displayed along with a
GOOD/BAD reading based on the programmed
tolerance.
To perform the GOOD/BAD inductance value test:
1.
Zero the test leads.
2.
Connect the inductor to the test leads.
3.
Enter the marked value, along with the “+” and “-”
tolerance of the inductor to be tested.
4.
Press and hold the INDUCTOR VALUE button.
5.
If the measured inductance value is within the
programmed value tolerance the display will show
“GOOD” along with the measured value.
6.
If the measured inductance value is outside the
programmed value tolerance, the display will show
“BAD” along with the measured value.
The Inductor Ringer Test
A shorted turn in many coils will go unnoticed with a
value test, since the shorted turn changes the inductance
value only a small amount. The patented Ringer test,
however, provides a fast and accurate GOOD/BAD
indication of non-iron core coils larger than 10 uH by
checking their quality or “Q” factor. The Ringer test is
sensitive enough to detect even a single shorted turn on a
coil. The ReZolver measures Q by applying a pulse to
the coil and counting the number of ringing cycles until
the ringing dampens to a preset level. A good coil will
indicate “GOOD”, and 10 or more rings will be shown
in the LC103 display. A shorted turn will lower the Q of
the coil, causing the LC103 display to read “BAD” and
show less than ten rings.
In addition to air core coils and RF chokes, vertical
deflection yokes, horizontal flyback transformers and
switching power supply transformers are reliably
checked with the Ringer test. The LC103 automatically
matches the coil impedance to the necessary testing
parameters for the inductor type when the proper
Inductor COMPONENT TYPE switch is selected.
Simply select the component type and press the
INDUCTOR RINGER test button to obtain the
GOOD/BAD indication. Refer to the APPLICATIONS
section of this manual for more details on inductor types.
The Ringer test can be performed with the coil in-circuit
without risk of damage. However, good inductors may
not normally produce more than 10 rings when
connected in-circuit unless the parallel impedance is
quite high. If an inductor does ring good in-circuit, it
does not have a shorted turn and can be considered good.
Fig. 16: The inductor COMPONENT TYPE switches
match the Ringer test circuits to the inductor
impedance.
To perform the Ringer test:
1.
Connect the inductor to the LC103 test leads.
2.
Select the proper inductor COMPONENT TYPE
switch.
3.
Press and hold the INDUCTOR RINGER button.
4.
Read the number of rings and the condition of the
coil as “GOOD” or “BAD” in the LC103 display.
Special Notes on Using the Ringing Test:
1.
Do not ring coils and transformers having laminated
iron cores, such as power transformers, filter chokes
and audio output transformers. The iron core will
absorb the ringing energy and produce unreliable
test results.
2.
Good coils below 10 uH may
not read “GOOD”
because the small inductance value may not
allow the
coil to ring. Compare the number of rings to a known
good coil. The patented Sencore Ringing test is based
on the Q of the coil. However, the readings on the
ReZolver may
not agree with the Q readings obtained
using a
“Q
Meter” or bridge. This is because the
Ringing test has been simplified to provide a simple
GOOD/BAD test, rather than a frequency dependent
reactance/resistance ratio.
COMPONENT TYPE
ALUMINUM
LYTICS
DOUBLE
LAYER
LYTICS
HIGH R
DOUBLE
LAYER
ALL
OTHER
CAPS
SWITCHING
TRANS-
FORMERS
TANTALUM
CAPS
CERAMIC
CAPS
YOKES &
FLYBACKS
COILS
