High Speed Testing
The new all solid state programmable current source
allows fast test algorithms. Test times are super fast,
increasing productivity and lowering labor costs. Typical
test times are:
1. Ramp up, verify ratio, iterate to test level, measure,
compare to limits, display results: 4 seconds
2. Polarity check and reversal: + 1 second.
3. Degauss function: + 1 second.
One advantage of high speed testing is low heating.
Due to the ramped modulation and low duty cycle of the
current waveform, the R.M.S.. heating of the CT under
test and test system components is approx. 1/5 that of
conventional test systems. Low heating allows smaller
and lighter test system components, making Model CT-
4000 smaller, lighter, more reliable and less expensive
than competitive equipment.
The Auto-Range software option is especially useful if
the CT to be tested is mislabeled or the ratio is not
known. Auto-Ranging software does not require the
operator to program a ratio. The test system will
automatically find the correct ratio for the CT under test
and display RCF and Phase data Auto ranging software
requires the Universal Reference.
In normal use, Model CT-4000 will allow the user to
program only the ratios defined in the test system
specifications. Other ratios will not be accepted and will
generate error messages. If the Model CT-4000 test
system is equipped with the Universal Reference**
option, then any ratio may be programmed and tested
within the allowable range of ratios and currents.
Universal Reference ratios must be integers. There is
no loss of accuracy when testing universal ratios.
Multiple Test Points
A test point is defined as a specific combination of ratio,
test level and burden. It is sometimes desirable to
measure CT RCF and Phase at various test points while
the CT is connected to the test fixture.
Two test modes are available:
1. Single point testing. If the single point test executive
algorithm is selected (by clicking on a desktop icon), the
displayed form will prompt the operator to select the test
conditions from the stored test program data base, or
enter the test conditions manually. Test conditions are
always checked for illegal data before testing can start.
When the operator presses the START button, measured
values of RCF and Phase are compared to test limits and
displayed. The RCF and Phase data may be printed in a
certificate and/or may be saved on disk (archived) for
future reference. Test Data saved to disk is in CSV
format suitable for Excel or Access.
2. Multiple point testing. If is desired to test a CT at
multiple points, such as at different test levels or burdens,
then the multiple point test executive should be used.
The multiple test algorithm prompts the operator to enter
the name of a user defined test sequence table. Each
sequence table contains a list of test programs. Each test
program in the list defines a different test point. The
multiple point test executive tests the CT test according
the test programs in the list, generating an array of RCF
and Phase data for each test program. The multiple point
RCF and Phase data may be printed in a test report and/
or may be saved on disk (archived) for future reference.
Saving the test data to disk takes only milliseconds.
Printing a certificate or report may take a few seconds,
but the multitasking capability allows simultaneous
testing and printing.