Which Burden Resistor for SCT 019

Hi,

I have searched the site and seems like the ideal burden resistor for a SCT 013 CT and a 5V Arduino is a 33 ohm resistor.

Some people seem to disagree, any thought on that?

Also, which would be the ideal resistor for the bigger SCT 019 CT that supports 5-200 Amp

Thanks

TrystanLea's picture

Re: Which Burden Resistor for SCT 019

I see there are a couple of different types of the SCT 019 variety: http://www.yhdc.com/english/productshow.asp?id=225

You wont need a burden resistor for the voltage output type.

Have a look at this page, it details how to calculate the burden resistor for the current type: http://openenergymonitor.org/emon/buildingblocks/ct-sensors-interface

mdecastro77's picture

Re: Which Burden Resistor for SCT 019

I have the SCT 019-000 that doesnt have a burden resistor

So it looks like that it's 6000 turns so the calculation for a 5V arduino gives me 53 ohm. Closest would be 51 ohm

Thanks

MDC

Jérôme's picture

Re: Which Burden Resistor for SCT 019

I agree with this calculation.

I reproduced the setup with the SCT-019-000 current sensor and a 54 ohm resistor (supposed to be 56 but I measured 54).

With this value, the calibration constant should be 6000 / 54 = 111.11 (precisely the default of the example sketch).

(Note that this resistor value "may be a little high to be able to read the full 200 A primary current" (Thank you Robert) but unless you need the whole range, it should not be an issue, I suppose.)

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