17
16
Application Notes
When measuring AC Amps of a motor there
are two types of measurements that can be
made, running current and in-rush or start-up
current. Start-up current will usually be much
higher than running current.
Set up the meter following the steps under
“Measurement Procedure” on page 16, and
then proceed with the following:
•
Clamp the meter around a single wire
and reconnect power to the device. Read
the current displayed on the meter. This
is the running current of the motor.
•
Disconnect power to the motor and put
the meter in PEAK HOLD mode.
Reconnect the power and read
the current displayed on the
meter. This is the in-rush or
start-up current
of the motor.
c. Measuring AC Amps
CAUTION!
Do not attempt to make a current measurement with
the test leads. The 291 measures the current by
clamping the jaw around one conductor (wire).
Clamping around more than one wire will result in
erroneous readings.
Instrument set-up:
FUNC.
BLACK RED
MIN
MAX
TEST LEAD TEST LEAD
READING
READING
A
NOT USED NOT USED
0.01A
700A
Measurement Procedure:
1.
Disconnect power to circuit to be measured.
2.
Set rotary switch to
A
function.
3.
Clamp the jaws around one conductor of the circuit
to be measured.
4.
Reconnect power to circuit to be measured.
5.
Read the current on the 291.
Optional Modes
•
HOLD:
Freezes the reading on the LCD.
•
PEAK:
Measures the peak amperage.
