I'm designing a energy monitoring system that is using split-core clamp current sensors to measure multiple high power lines(40+ lines at 300A each) in a MCB room of a building. I'm currently sourcing the current transformers and noticed that there are typically two types of outputs, voltage and current. I understand the only difference is that the voltage output has a burden resistor built-in the CT. My question is if there are any pros and cons in using one of it in terms of interference or accuracy?

The standard voltage output option seems to be either 333mV or 1V and the standard current output option seems to range from 30mA to 5A. Since most microcontrollers operate at 5V or 3.3V, is there a downside to increasing the burden the resistor, so that the output voltage increases making it easier to measure?

Lastly, if I were to use a 10 channel single-ended ADC on MCUs, and some resistors and capacitors to increase the voltage swing to be above 0V, will I face any significant inaccuracy or interference issues when connecting many CTs to the same MCU?

Any help or advice will be much appreciated thank you.

  • 2
    \$\begingroup\$ Increasing the burden resistor can cause non-linearity and also lead to core saturation. \$\endgroup\$ – Andy aka Nov 21 '20 at 15:43
  • \$\begingroup\$ CTs generally have a specific rating for the maximum burden (usually given in VAs) that the accuracy is guaranteed to. Also, assuming you intend to measure power not just current, you will also need voltage sensing. \$\endgroup\$ – SomeoneSomewhereSupportsMonica Jan 1 at 15:48

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