15
14
b. Measuring AC Volts
WARNING!
Do not attempt to make a voltage measurement of
more than 600V or of a voltage level that is unknown.
Instrument set-up:
FUNC.
BLACK RED
MIN
MAX
TEST LEAD TEST LEAD
READING
READING
V
COM
V/
Ω
0.1mV
750V
Measurement Procedure:
1.
Disconnect power to circuit to be measured.
2.
Plug black test lead into
COM
input jack.
3.
Plug red test lead into
V/
Ω
input jack.
4.
Set the rotary switch to the appropriate
V
function.
5.
Connect test leads to circuit to be measured.
6.
Reconnect power to circuit to be measured.
7.
Read the voltage on the 291.
Optional Modes
•
HOLD:
Freezes the reading on the LCD.
•
PEAK:
Measures the peak voltage.
!
Application Notes
Disconnect power from the
terminal block, find the fuse or
circuit breaker that controls
the block and turn it off.
Set up the meter following the
steps under “Measurement
Procedure” on page 15. Then
proceed with the following:
• Connect the red test lead to
the hot side of the block and the
black lead to the neutral side of the block.
Reconnect power to the block and read the
voltage on the meter. The reading should be
approximately 110V to 130V.
•
Disconnect power from the block and move
the red wire to ground. Reconnect power to
the block and read the voltage on the meter.
Typically less than 20V should exist from
neutral to ground. If 110V or above exists,
the block may be wired incorrectly.
