Plain clamp-AC amperimeter...

[Externet]

Regards.
Is there any addition/modification that can be done to a clamp meter to find the direction the sensed current flows ? Receiving ----> or <---- delivering ?

It would be for a solar inverter <----> utility grid tied monitoring. 230VAC split phase.
Just a LED would suffice as direction indicator. Or any other coil / current transformer gadget ?

 

[dick_freebird]

I think that all of these meters try too hard to be insensitive to direction.
But you might look for Hall sensors which do have directionality, find
one whose form factor, output and "neediness" fit up with the gear
you've got and now it's a specialty tool (direction finder).

Now if you have access to conductors, just tap two points as far apart
as practical and work DC voltage range down from max until you see
a stable significant reading. If voltage reads positive then current is
flowing from + lead position to - lead position, and the conductor's
finite resistance is your "sense resistor". You don't get to know value
but your other meters may give you that.

If current is very high then a compass will point across the wire. I'd
have to set up a test to say which direction of compass indicates
which direction of field-around, which is perpendicular to flow-through,
and how north/south relates to +/-, well, if I ever knew I've forgotten.

Not to say there couldn't be one that does want to indicate direction.
But I have not seen one.

 

[Externet]

Thank you, sir. Post meant for determining 'direction' of 230VAC. current flow using an AC clamp current meter. Or any circuit that could be built as to detect direction only, in clamp form. Similar? to directional RF power meter/sensor (SWR), capable of working at 60 Hz.

 

[FvM]

Current doesn't indicate direction of power flow, it's the product I*V. Respectively, if you tap one conductor of a single phase circuit with a clamp meter, you need to determine also voltage sign to calculate power flow. Under circumstances, a capacitive probe can do the trick for AC.

 

[KlausST]

Hi,

as FvM wrote, AC current flows in both ways.
You need a power meter that can show power direction, usually with "+ " and "-".

There are clamp meters able to measure power. One needs to read the datasheet if it is able to destinguish power direction.

Klaus

 

[Externet]

Thank you, gentlemen.
The gadget am after is then properly named an indicator of AC power direction (not AC current). Perhaps a power factor measuring clamp meter ? Or perhaps someone here knows a circuit using a clamp sensing plus AC voltage probing available as kit or buildable schematic ?

To the moment, found :

 

[BradtheRad]

I have connected a wire to a spigot or copper plumbing in a residence. Then I know it's ground. So by connecting a meter from there to a questionable wire, I get a clue whether AC power comes from the wire in question or from some other wire.

 

[betwixt]

Brad, I think the issue here isn't finding out which wire is live, it is finding out which direction current is flowing when there are two sources.

I have a similar issue here on a project I'm working on at the moment. Its a graphical LCD showing how much power is being produced locally and how much comes from the grid. There are two grid-tied PV inverters and one feed from the grid, all going into a varying load of zero to 10KW. Just measuring line current (with a clamp on) and line voltage doesn't give any indication of which source is pushing and which is pulling.

I've worked around the problem by using the internal MCU of the inverters to tell how much they are producing and subtracting that from the grid power. A negative figure says current is flowing towards the grid and shows as such on the LCD, it also doesn't add it to a tally of running costs. A positive figure means more is being drawn from the grid, that is also shown graphically but accumulates a running cost based on the cost per electricity unit.

It is very similar to a 'smart meter' but takes into account the generating side of the equation. All data is sent by Wifi so the LCD unit is portable within router range.

Brian.