harry wrote:
On Jan 1, 11:58 pm, John Williamson
wrote:
wrote:
As part of another project, would like to take some High Current DC measurements.
Depending how accurate they need to be, you can get a cheapish DC only
current meter with ranges of +- 100A and +-600 Amps from most decent
motor factors. Mine's made by Durite, Part No. 0-534-00.

They're sold for checking charging and starter currents without breaking
the circuit, you just put the wire into a channel on the back of the meter.

http://uk.picclick.com/2-X-VINTAGE-D...999596420.html

The e-bay auction's ended, but you get the idea...

I bought mine a few years ago, though. And no, it's not for sale, it's
too useful. :-)

--
Tciao for Now!

John.

The cheap high current ammeters have no coil but a bit of resistance
wire where the length changes due to the heating effect. Very
inaccurate and subject ambient temperature.
Some have a bimetal strip to work the needle.

This one has an internal magnet working against a spring. It works by
sensing the magnetic field round the wire. Think of the way a Hall
effect sensor is used, but without the electronic bit. It has no
electrical connection at all to the circuit under test and has no
internal electronics. Not terrifically accurate, but good enough for its
intended application.

--
Tciao for Now!

John.