Lehman Engineering Power Quiz
"Harmonics And True RMS"
Consider a non linear load which is being fed from a transformer. The load draws a
current that has a 60 Hz fundamental component of 10 Amps RMS and has a 3rd order harmonic
(180 Hz) component of 5 Amps RMS.
What is the total RMS value of the current that would be read on a True RMS
What is the Total Harmonic Distortion (THD) of the current?
Assume the load current has a 10A RMS, 60 Hz fundamental component as in the
original problem, BUT the 3rd order harmonic is now changed to a 5th order harmonic with
the same 5A RMS value.
Does the total RMS value of the current change due to the higher frequency of the
Will the THD of the load current remain the same, increase or decrease?