Pump Motors
25
Level 2
A.O.Smith
CONVENTIONAL MULTIMETER OR OHMMETER
An ohmmeter can be used to measure the resis-
tance of the various motor windings as well as to
test the insulation.
The ohmmeter will have numerous ranges from
R x 1 where the meter reads directly in ohms to
an Rx100K where the actual meter reading must
be multiplied by 100,000 for the actual ohm
value.
Before using an ohmmeter:
■
Make sure all motor leads are disconnected
from the power source.
■
Make sure the meter is adjusted to zero
before taking each reading.
■
All troubleshooting checks specify the ohm-
meter range to be used. If your meter does
not have the exact range, use the next higher
range.
DIGITAL OHMMETER/MULTIMETER
Direct reading digital ohmmeters are readily
available in the field. To use this type:
■
Make sure all motor leads are disconnected
from the power source.
■
Read instruction manual for the meter.
■
You do not have to set the ohmmeter to a par-
ticular scale as the meter displays the ohm
value up to the maximum capability of the
meter.
■
Install probes and take resistance readings in
the normal manner.
AMMETER AND VOLTMETER
Voltmeter Readings:
Install leads in bottom of Amprobe®. Select the
desired voltage scale. Take readings by touching
one probe to each of the lead line terminals.
Ammeter Readings:
■
Arrange leads so the jaws of the Amprobe®
will encircle one lead.
■
Set meter on maximum amp scale and encir-
cle jaws around one lead and take reading. It
may be necessary to reset to a lower scale.
