SCT-013-000 number of turns ?

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 ?

 

 

http://openenergymonitor.org/emon/node/156

Todd's picture

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.

glyn.hudson's picture

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. 

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.