R&D#23 A beginners guide to current transformers

In this video I will cover the basics of current transformers, how they work, some safety when using them, and how to set them up.

[@UnbornAssassin7]

Thanks for the handy video, very helpful for working at a project at uni

[@billhudson7537]

A serious matter, CTs should ALWAYS have a short circuit jumper installed until used. The theory is pretty heavy but I have seen an instrument imbedded into a concrete wall from a CT left open by mistake. Granted, it was in a power vault, but the theory applies even to MilliAmp outputs. They can bite, and have sharp teeth. Bill Hudson EE(Ret)

[@segarlinktech]

is great experiment video for CT application is apply in micro controller to measuring the power consumption of kw and amps thanks for this video

[@ClintMaas]

So lets say I want to measure the total current of my main panel at home (220). Do I need two CTs measuring each leg and then add them? I've been hearing mixed answers to this. One suggestion was to use one CT and have one leg looped backwards through the same CT. This is not an option in my application. But I do have two CTs if I need them.

[@vambans2412]

good one.thank you

[@lalogarcia6686]

great video!!! thank you!!

[@subirg123]

Please let me know if the maximum load is 400 amps then should i use 500/5 or 800/5 CT ratio for a three phase KWH meter. 2) if a higher capacity CT ratio is used for a kwh or ammmeter .........is there any problem !!

[@johndooley8837]

A diode is a non-linear device, it's resistance decreases as the current flow through it increases. That would probably explain your results.

[@_adamalfath]

It's nice explanation. You mention that when you shorted secondary CT it will only generate flowing current without potential? what happen if I used another CT to that previous one. I'm having trouble to managing 400/5A CT to be read by ADC microcontroller that have range 0-5VDC, my plan is theoretical use second CT to be outputting more manageable current like in milliampere order.

[@fixfaxr]

I'm missing an explanation of the divide-by-ten example, I'm thinking if your current transformer is 1000:1 ratio it would explain it since 100R * 1mA = 100mV , but I'm not sure if that is why. Thank you for the video.

[@lahcenasbayou9028]

how can I use? a CT for measuring MY cables current to be read by Arduino ADC to be used for showing the current measure in LCD

[@techtronixs7452]

How to design a ct for 20ma. It is possible. How to calculate a turn in primary and secondary

[@_Junkers]

Is the error caused by flux leakage?

[@SombraLocs]

How would you troubleshoot a CT?

[@subirg123]

What should be criteria for CT ratio selection !!

[@Cdswjp]

Thanks for the video…. Do people often cover up the hole in the center of the transformer w/ a metal cover?… I ask because I have a transformer from an old boombox/cd player that is fully encased in metal (except for where the wires come out of), and there’s a small toroidal core wrapped around the primary side’s 2 black wires, and Im wondering why it is there…. Its a 120v(ac)-to-12v(ac) single phase power transformer… it has 2 blackwires on primary side & 2 red on the secondary. Im wondering… could this actually be the same as the CT transformer u showed, except w/ the hole all covered up.

[@iraqresitance9663]

From Iraq well done

[@bobbauvian7700]

thank you. I wanted to make a circuit to turn something on or (close a contact) when sensing current in line using CT. what should I use.

[@jeffreyhunterbuilder]

an Arduino might be easiest.

[@gearhead0800]

Hello R&D#23, I am trying to monitor the accumulated run time of the new 240volt Hot Water Heater that I just installed at home. The H.W.H. has two T-Stats that each call in its own19Amp element. They operate non-simultaneously, i.e in an either/or manner. One for the upper tank the other for the lower portion of the tank. Both 120v legs pull approx. 18.75 amp when either heater is pulled in. Can I use a C.T. to operate an elapsed time clock of some kind so that I could know total number of hours that the H.W.H. runs over time?? Any help is very much appreciated. I can scan a sketch or answer any questions if needed. Regards

[@jeffreyhunterbuilder]

+gearhead0800 Yes, monitoring a water heater with a CT is possible, you will need the supporting circuitry of course, you can look up circuits on the google, then just add that to your A to D converter for the micro-controller and start counting the on time. Good luck.

[@gearhead0800]

+R&D Department thanks for taking the time to respond. I will check it out. Regards

[@gearhead0800]

+R&D Department just a word, I am a mech.eng. and have some electrical knowledge but I wish I had more knowledge of circuitry, that is why I subscribed to your channel.

[@ionsight91]

really useful information but theres too much bass in the audio like you have the mic too close

[@jeffreyhunterbuilder]

Thanks for watching and commenting, I have a new mic now hopefully it is better now.

[@falcon02012]

i am in

[@mr.e.484]

do they make 1 to 1 ratio ct's?

[@jeffreyhunterbuilder]

+Evan Perry Not to my knowledge, at least I've never seen one.

[@KramatUllah]

its not possible 1 to 1 ratio i think minimum 1000 to 1 ratio

[@whitefields5595]

Be careful here. Whilst it is correct to 'tweak' the burden resistor value to suit the application, remember that you can also distort the AC waveform on the secondary. I was tuning my CT to give 5V peak to peak for my microcontroller and when I put an oscilloscope on the output I noticed that the AC waveform collapsed it I took things too far. So be careful!