Test Products International 126 - Manual (Page 18)

19
e. MEASURING RESISTANCE
WARNING!
Do not attempt to make resistance measurements
with circuit energized. For best results, remove
the resistor completely from the circuit before
attempting to measure it.
NOTE:
To make accurate low ohm measurements, short
the ends of the test leads together and record the
resistance reading. Deduct this value from
actual readings.
Instrument set-up:
FUNCTION BLACK RED MINIMUM MAXIMUM
TEST LEAD TEST LEAD READING READING
Ω COM V Ω 0.1 Ω 40.00M Ω
Measurement Procedure:
1. Disconnect power to the circuit to be measured.
2. Plug the black test lead into the COM input jack.
3. Plug the red test lead into the V Ω input jack.
4. Set the rotary switch on the 126 to the
Ω function.
5. Connect the test leads to the circuit to be measured.
6. Read the resistance value on the 126.
18
Application Notes
When measuring resistance of a motor,
make sure the power is disconnected prior
to testing.
Set up the meter following the steps under
“Measurement Procedure” on page 17, and
then proceed with the following:
• Connect the red test lead to one power
input line of the motor and the black
test lead to the other power input line
of the motor. In most applications, if
the reading is OFL, the motor winding
is open.
• Connect the red test lead to the frame
of the motor and the black test lead to
the winding. In most applications, if a
reading of 0 Ohms is displayed, the
winding is shorted to the motor frame
(ground).