Burden Resistor calculation
This is how burden resistors are calculated for a given CT and desired range.
Burden Resistor Formulae
R: Burden resistor value in Ohm
Vadc: ADC reference voltage
- This is 3.3V for all RPICT3T1 RPICT3V1 and RPICT8/RPICT7V1/RPICT4V3 in version 3 and earlier.
- This is 4.096V for all RPICT8/RPICT7V1/RPICT4V3 in version 4 and 5.
Nturns: Number of CT sensor turns (see specs).
- SCT-013-000 is 2000 turns.
- SCT-019 is 6000 turns.
- SCT-006 is 800 turns.
Nturns can be deduced dividing primary current by secondary current. For example the SCT-013-000 is rated as 100A/50mA. Therefore we get 100/0.05 = 2000 turns.
Irms: Max current to be read in Ampere (rms)
Current Coefficient Formulae
This will compute ICAL.
ICAL: Current Coefficient
Nturns: Number of CT sensor turns
R: Burden resistor value in Ohm
Application
- For RPICT3T1 RPICT3V1 RPICT4T4v2.5 and also RPICT/RPICT7V1/RPICT4V3 in version 3
- For RPICT7V1 RPICT8 and RPICT4V3 in version 4
- For RPICT7V1 RPICT8 RPICT4V3 in version 5