Fluke 43B
Applications Manual
76
Harmonic (component)
A sinusoidal component of an ac voltage that is a multiple of the fundamental
frequency.
Harmonic Distortion
Periodic distortion of the sine wave. The waveform
becomes distorted when higher frequency components
are added to the pure sine wave.
(see also: Total Harmonic Distortion)
Harmonic Order
A number indicating the harmonic frequency: the first harmonic is the
fundamental frequency (50 Hz or 60 Hz), the third harmonic is the component
with three times the fundamental frequency (150 Hz or 180 Hz), and so on.
Harmonics can be positive-sequence (+), zero-sequence (0) or
negative-sequence (-). Positive-sequence harmonics try to run the motor faster
than fundamental; negative-sequence harmonics try to run the motor slower
than fundamental. In both cases the motor looses torque an heats up.
Order F
2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th etc.
Frequency
50
60
100
120
150
180
200
240
250
300
300
360
350
420
400
480
450
540
500
600
600
660
...
...
Sequence + -0+-0+-0+ - ...
If waveforms are symmetrical, even harmonics disappear.
Impulse (see Transient)
Inrush current
The initial surge of current required by a load before resistance or impedance
increases to its normal operating value.
K-factor
A number indicating losses in transformers due to harmonic currents. Higher
order harmonics influence the k-factor more than lower order harmonics.
The following definition is used in the Fluke 43 for computing the K-factor:
()
KF
hI
I
2
h
2
h
2
=
×
Where: h = harmonic order
I
h
= harmonic current as a percentage of the fundamental
To Next Page
Loading...
Need help?
General
