Current Transformer Testing and Analyzing

Date : 02/24/2023 

Reporter : Ly Chheang

Report Investigation Purposes:

Testing the SCT013000 current transformer of its output current compared with its input. We are going to try to calculate the input current with the measured output voltage.

Equipment: 

• Oscilloscope (Hantek DSO4202C)

• Current sensor probe (Hantek CC-65)

• LED light Array (24W)

• Power light bulb (60W)

Element under test :

• SCT0013000  (Beijing YaoHuadechang Electronic)

• 200 ohm metal film Resistor

Testing Diagram:

Testing Condition:

1. 24w LED light array

• Sampling resistor = 200 ohm

• CC-65 setting = 1mV/10mA

2. 60w Power light bulb 

• Sampling resistor = 200 ohm

• CC-65 setting = 1mV/10mA

Result:

1. 24w LED light array

Channels	Sensors	V rms Value (mV)	Cal_Current
C1 (Yellow)	SCT013-000	20.56mV	0.205A
C2 (Blue)	Hantek CC-65	16mV	0.16A

2. 60w Heath bulb

Channels	Sensors	V rms Value (mV)	Cal_Current
C1 (Yellow)	SCT013-000	30mV	0.3A
C2 (Blue)	Hantek CC-65	30mV	0.3A

* Calculation are in appendix

Finding:

The SCT013-000 is a somewhat safer and cheaper alternative. However the noise and amplitude of the AC voltage need to be dealt with in order to send the signal to the Raspberry pi.

⚠️We need to build a rectifier to transform the AC signal to DC. The signals are needed to amplify and filter out the noise to 3.3V logic level.

Appendix:

SCT013 output = 20mV

Using ohm's law we can calculate the output current from SCT013

Using the turning ratio of the transformer we can get the input current

CC-65 output = 16mV

Using the given ratio setting on the device   we can get the input curren