1. The AC neutra
l
w
i
res must be of sufficient gauge to
allow for harmonic current flow.
2. The distribution transformer must have additional cooling
to continue operation at its rated capacity, if it is not
harmonic-rated. This is because the harmonic current
flow in the secondary neutral wire is circulating in the
delta-connected primary winding, after it is reflected to
the primary winding. The circulating harmonic current
heats up the transformer.
3. Phase current harmonics are reflected to the primary
winding and they continue back towards the power
source. This can cause distortion of the voltage wave
so that any power factor correction capacitors on the
line can be easily overloaded.
We can use th
i
s
Meter to analyze components such as
power distribution transformers and power factor correction
capacitors.
6.2 General Applications
You can measure any conductor carrying AC unless this
conductor is at a potential above 600V AC or at a
frequency above 10KHz. True rms measurement yields the
effective current value.
1. Press the ON OFF pushbutton to turn on this Meter.
2. Clamp around the conductor to be measured. Be sure
the clamp jaws are securely closed, or measurements
will not be accurate.
3. Observe the display for true rms current flow.
4. Press the Hz pushbutton to measure frequency.
5. Press the HOLD pushbutton to freeze the digital
display, if necessary.
22 23
6. To soften readings, press the SOFT CREST
pushbutton once (SOFT displayed) or to measure half-
cycle peak amperes, press this pushbutton twice
(PEAK displayed). A crest factor (see 5.11 Using
Crest) other than 1.414 is an indicat
i
on of non-linear
current flow.
7. To record readings and to view readings, press the
MIN MAX pushbutton.
8. To clear RECORD, press the MIN MAX pushbutton for
2 seconds.
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