looking for AC current sensor

[st]

i suggest you simply get an electricity meter like the energy companies
use.
they are often available very cheap as surplus.
would be much more accurate as you can charge them the actual AH they
used...

if you buy a new there are also very small units (fit in a standard
automatic fuse slot).
but the normal (here black) unit with the spinning disk would be perfect.

another option to sense current is measuring the "return voltage" on the
nautral wire.
if you measure it over some meters it can be well enough to be sensed
clearly by a comparator.

these toroid converters are also a good idea.
sold as current transformer (i think) at any better parts supplier...

please don't bother to design your own, it isn't worth the work.
buy one where you simply stick one wire through (maybe some turns if low
current).
in this sensor there is a coil (depending on nominal current from several
hundred turns to one turn for power plant generator current measuring)
this generates a current proportional to the current in the mains wire.
it has to be converted to a voltage with a resistor (you shouldn't use
without because that can affect accuracy)


but this makes need for very complicated computer counter needing lots of
power, run all the time, etc etc.

simply use a energy meter like the professionals.

one option would be to use a "operating hours counter". these need mains
voltage (or 12v/24vdc) and display the hours
the voltage was applied. (like your car's miles counter)


st

 

[Vlad]

If you are interested only on the presence of current on the line, use
a current relay.
If the heaters are powered by 230 Volts you only need to sense one of
the lines.
If it was DC, I would suggest a modified reed relay . Easy to do make
from a regular reed relay

Vlad

i suggest you simply get an electricity meter like the energy companies
use.
they are often available very cheap as surplus.
would be much more accurate as you can charge them the actual AH they
used...

if you buy a new there are also very small units (fit in a standard
automatic fuse slot).
but the normal (here black) unit with the spinning disk would be perfect.

another option to sense current is measuring the "return voltage" on the
nautral wire.

Electric heaters are usually connected across the 230 volts and
consequencly there is no change on the current of the neutral wire.

Vlad