Shunt measurement of CT measurement

[FreshmanNewbie]

Which the better option for accuracy and cost?

I have a charger board to EV. For measurement, I'd like to have good accuracy as well as cost.
So, in that case, should I go ahead for current measurement with CT or shunt measurement with resistor?

 

[KlausST]

Hi,

I want to go on vacation. I want to go on an island. Good quality as well as cost. So in this case should I go by airplane or by ship?
This is not meant rude. I tried to give exatly the same informations for my vacation as you gave for your application.

Honestly:
Without any informations about quality, volume, cost, signal current, voltage, frequency range ....... how should we be able to give good feedback?

Give good information .. to get good feedback.

****

I´ve done applications for AC 2000V / 3000A: for sure I used a CT .. simply because of isolation. I could have used a simple CT, but I needed to use the one with "magnetic compensation" to also get DC residual information.

I´ve also done applications using resistors .. because of small size.

Klaus

 

[Easy peasy]

CT gives isolation

 

[D.A.(Tony)Stewart]

A vacation sounds nice right about now with this dump of snow. An EV sounds nice too . I wonder if can take us all on a vacation or is it a toy?

 

[D.A.(Tony)Stewart]

We expect specs for current and BW with a budget. If you have none. A length of cable feed can be your shunt with an isolated chopper INA and shielded pair. For low ESL it can be a folded length of cable and try to get 1 mV resolution 20 dB SNR. For ease get a CT and compare. See if you can prevent the EMI interference in your properly biased INA sense STP cable with DC supplied on a connector. Then compare spectral density and accuracy.

Nothing is cheap or accurate until you have specs and tools to compare with experience. Make a test plan.

 

[Externet]

Some expressions in Morse code allow only the ones who know the subject to respond; 'weeding out' who do not or unsure. I do not know if CT is center tap, or charging transformer, or computerized tomography. Why some posters assume everyone receives their telepathy ? Is it that hard to type ?

 

[D.A.(Tony)Stewart]

Google is your answer https://www.google.com/search?client=firefox-b-e&q=Shunt+measurement+of+CT+measurement

I used the shunt method to measure 10kA for a plasma Diffusion Bonder using 2 screws calibrated with a 10A CC supply for 100uV then tapped into the 6" solid copper arms going into STP wire that must be at 90 deg to weld current.

 

[crutschow]

current measurement with CT or shunt measurement with resistor

Is the current AC or DC?
CT's can only measure AC current.

 

[D.A.(Tony)Stewart]

Probably primary ac as the charger should already have a dc current sensor.

 

[KlausST]

I used the shunt method to measure 10kA

That´s impressive.
10kA is pulsed I guess.

What´s not clear. If there is 100uV@10A, then it´s 100mV@10kA, so 1kW of power dissipation. (plus all the wiring and connections around)
And copper has a rather huge thermal drift (temperature coefficient) ...

I guess I never had the idea to do 10kA measurement using a shunt. But seems to work.

Klaus

 

[FvM]

I do not know if CT is center tap, or charging transformer, or computerized tomography.

Wikipedia disambiguation also lists current transformer. The latest confusion about AC or DC measurement however substantiates your doubt. More likely the original poster is asking for a DC capable current transducer (hall sensor based). Better to tell unequivocally what you mean.