current transfromer/current transducer

[pisces12]

hi...

beside using the current transducer or current transformer, is there any other alternative that can be used to scale down the current from the ac supply?

 

[FvM]

Strictly spoken, only a current transformer scales down a current. A shunt resistor in contrast converts the current to a voltage, a di/dt sensor (rogowski coil) generates a voltage proportional to the current change in time.

 

[pisces12]

tq for the answer...

basically, i want to take the ac supply into the energy meter...i have selected the rating for the voltage transformer which is 230/6V but for the current not yet...how to select the rating of the current transformer?

 

[FvM]

I suggest to consult the solutions presented in energy meter chip application notes, e.g. from ADI. You should also
consider, that a general purpose voltage transformer introduces considerable phase errors and measurement nonlinearity.

 

[Rey25]

You can use a current transformer with current output. They are know as the current-to-current transformers. The CT will provide a current output proportional to the input current. Depending on your design, you can reduce the current to 5 Amp, 1 Amp, or custom design it to any current that you want.

See Magnelab current sensors for different current rating.

Rey

 

[zhqazi]

Depending upon your load requirements you select the CT primary and secondary ratio and their coil parameters/ratings.