Corefficient’s Testing Capabilities | Epstein Testing

The quality of an electrical transformer core is equal to the sum of the quality of each part. Corefficient guarantees only the best because we take the time to test each unit, from raw materials to final end-product.

Many different testing methods are employed throughout the manufacturing process, adding multiple levels of quality assurance. Here we would like to highlight our Epstein Testing capabilities.

With our state-of-the-art Brockhaus MPG 200 system, we test the magnetic properties of the electrical steel used in our transformer cores, including permeability and core loss. We employ both standard and custom Epstein frames. Each strip of steel is tested with different Tesla and frequency inputs, based on ATSM A717 methods.

The Technical Data for the Brockhaus MPG 200 system, according to their literature, is:

  • Repeatability | 0.1%
  • Comparability of the measured results | according to IEC60404 ff.
  • Setting accuracy of the nominal value | according to IEC60404 ff.
  • Maximum current | 40A peak
  • Maximum voltage | 100V peak
  • Coil connectors | up to 12 coils parallel
  • Operating mode | PC/ software
  • Model | table or cabinet version
  • Measuring frequency
    • 3Hz – 20kHz (optional DC)
    • DC with adjustable rise time for primary signals and flux alteration control d??/dt.
    • Optional for higher harmonics 10kHz up to 100kHz (in combination with an additional amplifier)
  • Power supply 3 x 220-440V AC, 50/60 Hz


It is vital that all electrical steel is tested before being laminated for core formation. The permeability of the raw material that makes up a transformer core is directly related to the core’s energy efficiency.

Several other testing methods are used in conjunction with Epstein Testing to provide our customers with quality assurance. To learn more about our other testing capabilities and the manufacturing process, visit  You can also call us with inquiries at (81) 2088-4000, or toll free USA at 1 (844) 202-1226.

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