Hi,
When you design CT front end circuit, how could you select R(Burden resistor) and amplifier gain? Why 0.1R are selected? Thanks.
Regards,
Xiaobing (Eric)
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Hi,
When you design CT front end circuit, how could you select R(Burden resistor) and amplifier gain? Why 0.1R are selected? Thanks.
Regards,
Xiaobing (Eric)
Hi Srinivasan,
Tks for your feedback. Here're system specification for your comments:
Primary current range: 0 to 100A,
Input current frequency: 50 or 60 Hz,
Accuracy requirement for 10% to 120% (or 100%) of full scale primary current: 0.5% (or 1%),
CT turns ratio 1:3000, C/CT-1206 from Kemet (Datasheet for reference: www.mouser.com/.../KEM_SE0204_C_CT-1104528.pdf). So pls suggest How could select appropriate parameters for CT burden resistance and amplifier gain? Tks.
Regards,
Eric
Hello Eric,
I assume you are looking for 10% of accuracy @ 100A.
Kindly go through CT error calculations (equivalent circuit) using internal details which needs to be obtained from CT manufacturer.
Knowing full scale voltage needed @ ADC input you can compute Amplifier gain required from burden calculations from CT equivalent circuit.
Vs=Ib*Rs (Ib is burden current and Rs is burden resistor)
The design document error budget tool will help to compute total non adjusted error to be expected @ amplifier output.
Regards,
Srinivasan