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Calibration constants

Submitted by electrophile on Tue, 26/04/2016 - 12:39

Hi, I've been reading the documentation here on OEM for the past couple of days and its really insightful. Thank you for putting this out here. 

For the current measurement, I'm using a Bourns 53150C current transformer with a turns ratio of 1:150. Datasheet is available here. This is rated for 10A maximum current. Now my ADC can tolerate upto 1.5V on its input and hence for the rated current of 10A I need to output 1.4V. This gives me the R(burden) value of 21R. 

Hence,

Current Constant = (10 ÷ 66.67m) ÷ 18 = 8.333. 

[Isec = Ipri x Npri/Nsec = 10 x 1/150 = 66.67m]

Is this calculation correct?

Also I don't quite understand how this line in the voltage constant description is derived:

voltage constant = 230 × 11 ÷ (9 × 1.20) = 234.26

Any help would be really appreciated!

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Robert Wall's picture

Re: Calibration constants

Submitted by Robert Wall on Wed, 27/04/2016 - 09:34.

It is all spelled out in the Building Blocks page about Calibration theory. It's only the voltage ratio from your ac adapter = 230 ÷ (9 × 1.20) and the voltage dividers (11)!

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