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Phil Allison[_2_] Phil Allison[_2_] is offline
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Default Clamp meters: Peak vs. In-rush?


"Shaun"
"Phil Allison"
"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.


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.


** Fraid that is a very silly and persistent myth.

You have obviously NEVER checked it out.


Think about it.



** That is very stupid and very rude.

Read this then **** off.

http://en.wikipedia.org/wiki/Inrush_current



..... Phil