Plug packs: Difference between revisions

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==Waveforms==
Charger input waveforms, 0.2A/square, screen edges and centre are the input voltage zero crossings
Charger input waveforms, 0.2A/square, screen edges and centre are the input voltage zero crossings


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White wallwart Bestek NA0241WAA, XO1.5 running 93% charge 240V input
White wallwart Bestek NA0241WAA, XO1.5 running 93% charge 240V input


==Harmonics==

The load is well balanced with respect to leading/lagging power factor, showing only a slight leading or capacitive power factor. The waveform is very rich in harmonics. This could lead to overheating in transformers and generators due to eddy currents.
The load is well balanced with respect to leading/lagging power factor, showing only a slight leading or capacitive power factor. The waveform is very rich in harmonics. This could lead to overheating in transformers and generators due to eddy currents.


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[[File:Plugpack harmonics.xls]]
[[File:Plugpack harmonics.xls]]

==Refs==
http://www.idc-online.com/technical_references/pdfs/electrical_engineering/Generators_and_nonlinear_loads.pdf

Revision as of 12:03, 4 December 2010

Waveforms

Charger input waveforms, 0.2A/square, screen edges and centre are the input voltage zero crossings

Chargerwaveform1.jpg

Green wallwart AD5953 ALF, XO1.5 running 93% charge 240V input

Chargerwaveform4.jpg

as above but run on battery power to 80% then plug in

Chargerwaveform2.jpg

Green wallwart Delta ADP17FBA, XO1.5 running 93% charge 240V input

Chargerwaveform3.jpg

White wallwart Bestek NA0241WAA, XO1.5 running 93% charge 240V input

Harmonics

The load is well balanced with respect to leading/lagging power factor, showing only a slight leading or capacitive power factor. The waveform is very rich in harmonics. This could lead to overheating in transformers and generators due to eddy currents.

A harmonic analysis on the following approximation of the waveform

Assumed waveform.jpg

yielded this result

Fourier analysis.jpg

File:Plugpack harmonics.xls

Refs

http://www.idc-online.com/technical_references/pdfs/electrical_engineering/Generators_and_nonlinear_loads.pdf