Figure 14-31.Testing for an open
winding with a ohmmeter.
Watch the digital readout in the
meter as the check is made. Each reading
should appear to be approximately 0 ohms,
since winding resistance is usually less than 10
ohms. If, during the check, the resistance
digital display remains blank (infinity), an
open or break exists.
Voltmeter Test Procedure
T h e p r o c e d u r e f o r c a r r y i n g o u t a
voltmeter test is as follows:
Ensure the power is on and all wires
are properly connected to motor terminals.
With the voltmeter set on the proper
scale, place the leads across the R- and
Read the voltmeter.If the motor
shows line voltage, the motor is energized and
should be operating. The connections are
similar to that shown in figure 14-31.
Test Lamp Continuity Check Procedure
The procedure for conducting a test lamp
continuity check is as follows:
A simple test lamp consisting of a
power circuit plug, two flexible insulated wires
with clip leads, and a 25-watt socket with a
bulb is used. Figure 14-32 shows the test
Ensure the power is OFF, discharge
all capacitors, and remove the motor terminal
Make a continuity test through both
windings by attaching clips across the
C-terminal, then do the other terminals one
at a time. Now plug the test lamp into a
receptacle. If the bulb fails to light, there is
an open winding.
In an electric motor the winding turns lie
side by side with only the insulating varnish
separating one loop from another. When one
loop of the copper wire contacts another, the
Figure 14-32.Testing for an open
winding with a test lamp.