Product Tutorials

Power Meter Tutorials

Background

Single Phase, Sine Wave Theory

AVERAGE POWER

Long time the power of steam and explosion engines was expressed in Horse Power (Hp, Pk).
Also the first electrical DC-current engines were compared for their maximum delivered power to their predecessor and consequently expressed in Horse Power.
In AC current driven engines, the delivered power is changing continuously every period.
You could specify such engine like :

In order to compare the performance of AC-engines with other engines, the term AVERAGE POWER was introduced.

AVERAGE-GENERAL

Example Average (1)

Example Average

Example Average (2)

Example Average

AVERAGE CURRENT

The AVERAGE value Iav of an Alternating Current (AC) is expressed by that Direct Current (DC) which transfers across any circuit the same net charge as is transferred by that alternating current during the same time.

AVERAGE POWER

If power P(t) is a PERIODIC function of time t with period T, then the Average Power is:

This is not only true for sine waves, but for any other periodic waveform.

RMS-CURRENT

The RMS value of an Alternating Current (AC) is given by that Direct Current (DC) which when flowing through a given circuit for a given time, produces the same HEAT (= Energy) as produced by the alternating current when flowing through the same circuit for the same time.