Interface a CT with Arduino UNO

Other Hardware Sensors
1

Hi,

I have a CT (model number: SPCT-62/30-75/5A-VA1-CL3-CE, datasheet: https://www.selec.com/product-details/special-type-current-transformer) and want to calculate the burden resistor value. It is 75/5A.

Note: I am gonna measure a max. current of 3A.

Can someone help me figure out the burden resistor? I plan to use this circuit.

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What output voltage do you want from the burden resistor?

3

Your CT has a current ratio of 15:1, so 3A RMS in will result in 3 / 15 = 0.2 A out. 0.2 * 1.414 = 0.283A peak or 0.566 peak to peak. If desired output V is 4.667, resistance will be 4.667 / 0.566 = 8.2 Ohms. Resistor power dissipation will be 0.2A ^2 = 0.04 * 8.2 = 0.328W, I would use a 1 Watt resistor.
Double check my math. :grin:

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4

Thanks for the reply. I just wanted the methodology. You provided it. (Y) I'll double check math. Thanks again!

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