"Phil Allison" wrote in message
...

"daestrom"

Reading the app note it seems that Fluke designed there 33 meters to read
the symetrical currents for motor starting.

But as you mentioned, large inductive loads often have a DC offset
component to their starting current. This comes as an artifact of
closing the starter when the sine wave is not at zero-crossing

** Fraid you have got that all wrong.

The way to *guarantee* very large inrush surges ( with transformers and
transformer based PSUs) is to switch on at the zero crossing of the AC
voltage.

Cos doing this generates the maximum degree of magnetic saturation in the
core.


I wonder if Fluke deliberately filter out the DC offset just so they
don't have to explain why the reading changes each time you start the
motor :-)


** Fluke make no specific claims about the accuracy of their "inrush
surge" detection circuitry.

But I would not doubt is does the job required, as far as motors and
circuit breakers are concerned.


.... Phil

*******I'm afraid that YOU have it all wrong

Switch on power at or close to the voltage maximum on the AC sinewave
creates the biggest transient ( surge current) in equipment with a magnetic
core. Think about it.

Shaun