HT HT22D Manual De Instrucciones página 27

2. GENERAL DESCRIPTION
The instrument carries out the following measurements:
•
DC Voltage up to 600V
•
AC TRMS Voltage up to 600V
•
AC TRMS Voltage on VFD devices (downstream variable
frequency drivers - inverters)
•
DC Current up to 10A
•
AC TRMS Current up to 10A
•
Resistance and Continuity test
•
Frequency
•
Duty Cycle
•
Diode test
•
Capacitance
Each of these functions can be activated by means of the
appropriate switch. The instrument is also provided with a
HOLD/ , MODE, RANGE and H
refer to § 4.2. The instrument is also equipped with a white light
torch and an Auto Power OFF function which automatically
switches off the instrument 15 minutes after the last time a function
key was pressed, or the rotary switch was turned
2.1. TRMS/MEAN VALUE MEASURING INSTRUMENTS
Safety testers for alternate parameters are divided into two big
families:
•
MEAN VALUE instruments: instruments which measure only the
value of the wave at the fundamental frequency (50 or 60 Hz)
•
TRUE ROOT MEAN SQUARE instruments, also defined as TRMS:
instruments which measure the true root mean square value of
the quantity under test.
•
In presence of a perfectly sinusoidal wave, both families provide
identical results. In presence of distorted waves the readings are
different. Mean value instruments provide only the value of the
fundamental wave while True RMS instruments provide the
value of the entire wave, including harmonics (within the
passband of the instrument). Accordingly, if the same quantity
is measured with both kinds of instruments, the measured
values are identical only if the wave is purely sinusoidal. Should
it be distorted, True RMS instruments provide higher values than
medium value instruments
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button. For their use, please
HT22D