How much amperage can an alternator support? no really...

[syljay]

Huw,
Now you got me curious. So, I looked it up.

"For non-contact DC current measurements, the probe wraps around the 
current-carrying wire, but instead of a current transformer, there is 
a small gap in the magnetic metal (of the probe) that has a 
Hall-Effect sensor in the gap. DC current will produce a non-varying 
magnetic flux, but the Hall-Effect sensor will measure it's strength.

The magnetic strength is proportional to the DC current, and either 
analog or digital processing can calculate the current from the 
specifications of the Hall sensor, the probe dimensions, etc.

The wiki article has a good graphic about 1/2 way down the article:
http://en.wikipedia.org/wiki/Hall_effe... "

Good site explaining the differences between AC and DC current 
measurements using clamp style meters - with diagrams.
http://www.kew-ltd.co.jp/en/support/mame_02.html

So, we were both right.

The normal run-of-the-mill DMM used by electricians wont measure DC 
current via the clamp. One has to spend more money to get a clamp 
meter that measures both AC and DC currents.
Fluke has seven clamp meter models. But, only 2 measure DC current.


SJ in NJ

---------------------------------------------------

 >> Inductive current meters depend on expanding and collapsing
 >> electromagnetic fields - - as in A/C current.
 >>
 >> A current thru a wire produces a magnetic field around the wire.
 >> Passing a wire thru a magnetic field produces current in the wire.
 >> A stationary wire in a stationary magnetic field produces nothing in
 >> the wire.
 >>
 >> DC current will produce a field around a wire . . .but the field 
stays
 >> constant. No expanding and collapsing fields to produce current in 
the
 >>   meter inductive pickup - hence, no reading.
 >>
 >> Correct me if I'm wrong.


I think you might be wrong, based on "personal experience".

I agree that it is much easier to measure AC via inductive tools than
DC, but I did see it done.

-- Huw Powell