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Quick Fixes for Core Loss Testers

Frustrated by setup? Need help troubleshooting your core loss tester? We’re here to help. We’ve compiled a list of common troubleshooting questions with our CLTs and some quick steps that will help you get back on track in no time. ______________________________________________________________________________



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• General Core Loss Tester Checks

  • Reboot the system to verify the issue is still present.
  • After disconnecting the power, check for loose wire connections.
  • Check all fuses for proper setup and functionality.
  • Re-install main cable to ensure a secure connection.


• Cable High Error

  • Your core loss tester will error out above 2000 amps per main cable. If you are trying to achieve 2000 - 4000 amps, please refer to the manual for the dual cable setup. (Refer to Figure 1)
  • If available, try testing the core at a higher voltage tap.
  • If a higher tap is not available, you may need a higher capacity core loss tester to successfully complete the test. Call the IRD sales team to help you evaluate your options.


• Cable Low Error

  • Check to make sure the main cable is completely connected.
  • Verify that the meter connector (green plug) is fully inserted on the rear of the meter.
  • Next, check to make sure the wire connections on the current transformer are tight, and that no damage has occurred to either the connections or the current transformer.


• Contactor Doesn’t Engage, or Unit Doesn’t Energize

  • Check to make sure the main cable is fully connected.
  • Check line fuses:
    • Older core loss tester transformers have three fuses located on them.
  • Press meter power button. Verify 120 VAC is present at the 5 AMP SSR and the contactor.
    • On units with a rheostat, check to make sure the zero switch is engaged.
  • Verify that the contactor is fully operational.


• Meter Watts Display is Zero, or Does Not Increase Past 100

  • Check to make sure the flux cables are connected properly and are routed in the correct direction. (Refer to Figure 2)
  • Check to make sure the flux cables and meter connection (green plug) on the back of the meter are secure with no loose wires.
  • Replace flux cables. Cables can sometimes be faulty even after passing a continuity test. Call the IRD sales team to help you evaluate your options.


• Core Loss Tester Doesn’t Reach Target

  • If available, conduct your test at a higher voltage tap or with a dual cable setup.
  • Evaluate the test data inputted into MP7 for any errors.
  • Check to make sure no other metal is within range of the tested frame. Other metals can interfere with testing.
  • Utilize a larger capacity core loss tester. Some cores require a higher power rating than would be expected with their data. Call the IRD sales team to help you evaluate your options.


• Core Loss Tester’s Impedance Breaker Trips During Test

  • Verify that your incoming supply voltage is correct for your core loss tester. Ensure you are not seeing the voltage drop severely during operation.
  • Contact the IRD sales team to help you evaluate your options.



Not every problem can be fixed quickly – but either way, we’re here to help. Read through the list of frequent troubleshooting questions, and if yours didn’t make the list, don’t hesitate to contact us! We’re happy to help you through any trouble as quickly and painlessly as possible. Email us at sales@IRDproducts.com or call (502) 366-0916.








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