If the current is exceed the specified amperage, it will sound.
There are different approaches. With AC currents, I can use traditional current transformers, and then use a meter relay like this http://www.crompton-instruments.com/meteranalogue.pdf This would be the simplest method. Otherwise, put the CT output into a simple rectifier and a comparator. Use the rectified signal to drive a panel meter.
Select as Best AnswerUndo Best Answer
Wow, that was quick. Thanks a lot, I'm a beginner and never know there's a meter relay. I think it'll do the job ;)
For something like you're doing, for simplicity, and reliability, the meter relay is a lovely little thing. Steve
What kind of current, AC or DC ? What level 1A, 10A, 100A ? Steve
Sorry, I should be more specific. It's a AC current 380V (3-phase), and the current is around 10-100A depends on the machine. Does it differ so much in the circuit schematic between 10 and 100A? Or it's a matter of larger capacity of the components? Thanks again. :)