Ac Voltage Measurements - Sonel CMM-40 Manual De Uso

5.2

AC voltage measurements

Risk of Electrocution. The probe tips may not be long
enough to contact the live parts inside some 240V outlets for
appliances because the contacts are recessed deep in the
outlets. As a result, the reading may show 0 volts when the
outlet actually has voltage on it. Make sure the probe tips are
touching the metal contacts inside the outlet before assum-
ing that no voltage is present.
Do not measure AC voltages if a motor on the circuit is being
switched ON or OFF. Large voltage surges may occur that
can damage the meter.
In order to realise a measurement of AC voltage, it is necessary
to realise the following actions:

Set the function switch to the VAC/Hz/% position,

with the RANGE button set the measurement range manually
if necessary,

Insert the black test lead banana plug into the negative COM
jack. Insert red test lead banana plug into the positive V jack,

Touch the black test probe tip to the neutral side of the circuit.
Touch the red test probe tip to the "hot" side of the circuit,

Read the voltage in the main display and the frequency in the
right auxiliary display,

Press the MODE button to indicate "Hz",

Read the frequency in the main display,

Press the MODE button again to indicate "%",

Read the % of duty cycle in the main display,

Press EXIT (AC+DC) for 2 seconds into the function of
AC+DC. Test DC and AC True RMS,

Having done the measurement disconnect the test leads from
the meter.
52
WARNING:
ATTENTION!
CMM-40 – USER MANUAL