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The Model 3900 Computer Controlled Automated Core Tester is a computer controlled system containing the necessary instrumentation to perform core measurement tests on various core sizes. The equipment used to perform tests consists of the following:

  1. Computer Controller with keyboard, mouse and monitor.   Computer is windows based with windows based software to control tests.
  2. The Model 3900 Core Tester Chassis
    1. Chassis contains hardware for flux voltage measurements, RMS current measurements and appropriate shunts and relays needed to test cores.  This chassis also has provisions for primary and secondary field connections and digital I/O connections.
  3. Laboratory grade high current power amplifier.
  4. Precision Dual Rail Linear Actuator with servo motor.
    1. This Linear Actuator is used to make primary, secondary and digital I/O connections through center of core to be tested.  This  Linear Actuator has provisions for outputting encoder for exact positioning.
  5. Light Screen
    1. This Light Screen provides protection to user when test is implemented. 

Special Donart core test programs are provided for testing and calibration. Donart core test program provides test data screen to select test type and ability to enter test information needed for executing core tests.

Types of tests are menu selected. Each type of test has a similar set of menus to lead the operator through data entry. Default values chosen for the application minimize operator entries.

An internal calibration system permits daily or weekly checks of instrument operation under sine wave conditions. Not only is the test performed automatically after being selected by the proper menu, but the computer automatically computes and presents repeatability and percent deviation from the correct value as a printed copy.

The standard system is configured for testing at power line frequencies only. Both program and hardware changes are necessary for the system to be used to test at other frequencies.


Core Tester Specifications

Parameters Measured
  1. Primary RMS exciting current
  2. Primary peak exciting current
  3. Secondary flux voltage
  4. Net watts

Default Test Points

Test Point (Tesla)
  1. 1 Tesla approx.

Note: Induction is sample dependent

Test Frequency 60 Hz
Test Result Data
  1. V Flux
  2. Specific Core Loss (Watts/lb)
  3. RMS
  4. Watts Net
Operator Entered
1. Inside Diameter Numeric
2. Outside Diameter Numeric
3. Sample ID 10 Alpha/Numeric
4. Operator ID 3 Alpha/Numeric
5. Density 7.5-7.85
6. Weight Numeric up to 20,000 Grams
7. Induction

1 Tesla (Upto 12,000 Grams)

8. Max Watts Numeric
9. Length Numeric
10. Width Numeric

System Specifications

Excitation Power
Voltage 0 to 12 Volts
Current 120 Amps
Frequency Line Frequency (60 Hz)

Minimum Full Scale Ranges

Volts 2 Volt Full Scale
Current 0.01 Amps Full Scale
Power 0.01 Watts Full Scale (net)

Ranges (approximate- based on samples of nominal weight and quality)



  1. 1.3 Tesla for cores up to 5000 grams
  2. 1 Tesla for cores over 5000 grams
Core Loss 0.1 to 60 watts net