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.


 Non-Standard Ratios


 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.

Text Box: Series CT Automatic Test System Highlights


 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.


**Patent Pending