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214

Dran-View 6 User Guide

19.1.5. Equations to recompute waveforms from Normalized Transforms

f( t ) = normalized cosine transform

f( t ) = normalize sine transform

The above equations will generate the original signal just like the equations shown

for un-normalized transforms. Note that if you drop the nφ term from either

equation, what remains would be the equation required to redraw the original signal

phase shifted φ modulo 360 degrees (of the fundamental).

19.1.6. Power Dissipation Watts

Before discussing harmonic watts, terms are defined as follows:

The average steady state power dissipation, P

Average

, for an integral number of

cycles of a sinusoidal current driven by a sinusoidal voltage is:

Average

= V

RMS

* I

RMS

* cos θ

Where

RMS

= RMS Voltage applied to the current.

RMS

= RMS current in amps.

θ = The phase difference between the volts and the current using volts as the

reference (i.e. if volts are referenced at 0 degrees (its display looks like a sine wave)

and the associated current is at 90 degrees (it looks like a cosine wave) then θ = 0° -

90° = -90°+360° = 270°). Using this convention (keeping volts at 0 degrees), we

find that when θ is in the first and fourth quadrant (when θ is 0° to ± 90° degrees

but not equal ± 90° ) P

Average

is positive (power goes to the load). The second and

third quadrants (90°< θ <270°) generate negative power (i.e. your “load” is actually

a generator; this usually means your probe is on backwards). When θ is exactly 90°

or 270° no active power is generated (P

Average

= 0). In this special case the power is

pure reactive. If θ is 90° then it is pure inductive. At 270° it is pure capacitive.

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Dranetz Guide Guía de usuario Pagina 214