610573 Engineering Electrical- Doc

ENGINEERING ELECTRICAL

610573-ENGINEERING ELECTRICAL
QUESTION 1
State which symmetry and harmonics are likely to be present (odd, even or both) in Figures 1 to
5 below. State also whether there are any phase shifts (+/- /2 or +/-) and their approximate
periodicity.
Solution:
Figure 1:
The half cycle of positive axis is variant from the half cycle of negative axis. It specify that the
waveform consists of either
1) Even and fundamental harmonics in out of phase with positive and negative half cycle.
2) Fundamental, even and odd harmonics initially in out of phase with half cycle of positive and
negative waveform.

Figure 2:
Half cycle of negative is reversed. The negative half cycle is similar to the positive half cycle. It
specify that waveform consist of odd and fundamental harmonics only.
Figure 3:
The positive half cycle is variant to the negative half cycle. It specifies that the waveform sonsist
of either

1) Even and fundamental harmonics in phase with negative and positive half cycle at initial
point.
2) Fundamental, even and odd harmonics initially in phase with positive and negative half cycle.
Figure 4:
The positive half cycle is similar to the negative half cycle. It specifies that the waveform consist
of odd and fundamental harmonics in out of phase with positive and negative half cycle.
Figure 5: