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High Current measurement using Arduino? Answered

I need to measure Current from a welding machine to make a alarm if it goes down below some level for ensuring better quality.The current normally set is of the order of 200A max with around 100V DC.Not sure if i could use some clamp-on meters and decode the values. Shunt resistors may be a better option. But to make a signal conditioner to convert the ma output will be a problem i guess..is there something i can do with Arduino.. any ideas guys....?

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LargeMouthBass
LargeMouthBass

9 years ago

There are clamp on meter accessories for use with DMMs for about $50 that can measure hundreds of amps. The output is usually something like 1mV or 10mV per amp. The one I have can measure low frequency AC (less than 400Hz) and DC.

The clamp output could then be fed to an op amp for extra gain (if needed), followed by a comparator that would drive an output high or low when the current is out of the desired range.

Thats the most simple arrangement I can think of. If you can program any kind of micro then you could add a lot more smarts to it, otherwise the alarm would be going off every time the arc extinguishes.

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rickharris
rickharris

9 years ago

You can buy clip on amper meters that have an external output to feed data to other things such as your micro.

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steveastrouk
steveastrouk

9 years ago

What kind of welder is it ? If its an inverter type, you might be able to tap the information inside it anyway.

For 200A, I'd be inclined to use a hall-effect sensor.

Steve

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mpilchfamily
mpilchfamily

9 years ago

Use a shunt resistor and a voltage meter. A 1 ohm shunt will read 1mV for every amp going through the shunt. You can get a simple panel meter and mod it into the face of the welder.

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steveastrouk
steveastrouk

Answer 9 years ago

...and will dissipate 40kW !!!!

A 1 ohm resistor will read 1 volt for every amp. Perhaps you meant a 1mOhm resistor ?