Simpson 260 Series - AC Voltage Measurement: 0-500 V Ranges

Operation
410 AC VOLTAGE MEASUREMENT
0-2.5 THROUGH 0-500V RANGE
Branch and distribution circuits (120/240/480V etc.)
can deliver dangerous explosive power momentarily into
a short circuit before the fuse/breaker opens the circuit.
Make absolutely certain that the instrument switches
are set properly, jacks are connected, and that the cir-
cuit power is turned off before making connections to
such circuits (refer to paragraph 4-7-d).
4.10.1 The 260 responds to the average value of an AC wave-
form. It is calibrated in terms of the rms value of a pure sine
wave. If the waveform is nonsinusoidal, and depending upon its
waveform, the reading may be either higher or lower than the true
rms value of the measured voltage. Thus an error may be intro-
duced if the 260 is used to measure a nonsinusoidal waveform.
Also, accuracy is lessened at higher input frequencies (Figure 4-2).
4.10.2 Before proceeding with the following stpes, review the
Safety Precautions in Paragraph 4.2.
a. Set the function switch at AC (Figure 4-3).
b. Set the range switch at one of the five voltage range positions
marked 2.5V, 10V, 50V, 250V or 500V. (When in doubt as
to actual voltage present, always use the highest voltage range
as a protection to the Instrument. If the voltage is within a
lower range, the switch may be set for the lower range to obtain
a more accurate reading.)
c. Plug the black test lead into the — COMMON jack and the red
test lead into the + jack.
4-10