AC Current Polarity

[richxtlc]

Depending on the CT is does care. Emon Demon CT's only work if you install them in one direction

I don't know what an emon demon ct is, but a ct connected to a relay or an ammeter is a magnitude measuring device. It does not care what direction the current is flowing. If you want directionality, you must provide either a reference voltage or reference current for the relay to determine the proper direction. Wattmeters, varmeters, all work on the relationship between the current and voltage and the direction of current thorugh the ct. The polarity marks on the ct only matter when directionality is important.

 

[LarryFine]

I don't know what an emon demon ct is . . .

Check it out: http://www.emon.com/products_sensors.html

 

[richxtlc]

Check it out: http://www.emon.com/products_sensors.html

Thanks, it was just as I though, the metering is for watts and direction is important for proper indication. If it we just connected to an ammeter or OC relay it wouldn't make a difference.

 

[ggunn]

How about the wave at a stadium. The people (electrons) just stand up and down, but the motion (current) of the wave "moves" around the stadium. Too simple?

Actually, that's not far off the mark. Electricity in wires moves at a respectable fraction of the speed of light, but the individual electrons are nearly stationary by comparison.