Hi,
Very interesting project.
I bought the SCT-013-000.
I saw this page : http://openenergymonitor.org/emon/node/156
But I have a problem, I have not the number of turns so I can't calculate the burden resistance.
How can I do ?
SCT-013-000 number of turns ?
Submitted by Guest on Fri, 30/12/2011 - 10:45»
Re: SCT-013-000 number of turns ?
We know that the CT will produce 33mA on the secondary (Is) when 100A is present on the primary (Ip). The number of turns (Ns) is governed by the following equation:
IP*1 = IS*NS
So, Ns = 100/0.033 = 3030.3030
I'd assume 3000 turns since the 33mA rating is probably 33.3333mA. Regardless, at the end of the day what is important is the burden resistor you choose. 56 Ohms is probably a good choice and what I used. A larger value could be used if you only plan on measuring small currents.
Using a 56 Ohms burdon resistor, you would produce 1.848 Volts when measuring 100A on the primary (V = I*R = 100*0.033). If you have a 2.5V offset and are using a 5V reference voltage, everything should be within tolerance.
Re: SCT-013-000 number of turns ?
Testing has proved the datasheet (seedstudio) we linked to be incorrect. The SCT-013-000 has been measured to output 54mA @ 100A. This is consistant with the manufacturer datasheet. We have updated the datasheet link on the documentation page: http://openenergymonitor.org/emon/node/156.
http://openenergymonitor.org/emon/sites/default/files/SCT013-000_datasheet.pdf
This works out as 1852 turns.