<p align="left" class="headers2"><strong>Identifying Leads of a Nine Lead Three Phase
Motor </strong></p>
<i><b>
<p align="justify"></b></i>For the purpose of this project, a lantern battery of six or
nine volts works best. Use a DC volt-ohm meter with a 20K ohms per volt DC scale. Battery
and voltmeter leads should be properly identified. Alligator clips should be used on both.
The motor must be completely assembled. Test the nine leads for continuity with the
ohmmeter to determine whether the motor is star (wye) or delta connected. The delta
connected motor will possess three sets of three leads with continuity between them. On
the other hand, the star connected motor will have only one set of three leads with
continuity between them, and three sets of two leads with continuity. Following are
specific steps to take when identifying leads of both a star connected and a delta
connected motor. Refer to the diagrams on the following page for further details.<b><u></p>
<p align="justify">Delta Connected Motor</u>:</b></p>
<p align="justify">Using an ohmmeter, identify the three groups of three leads. Separate
these groups by tying them with tape. Attach leads to a pair of wires in a group, and
observe the voltage drop from each pair of energized leads to the third lead in that
group. Continue until a combination is found that gives a voltage drop from each of the
energized leads to the third lead equal to one half of the battery voltage. The lead
located halfway between the other two will thus be the corner lead of the delta. Repeat
this for each group of leads, marking the corner leads #1, #2, and #3.</p>
<p align="justify">Next, use the inductive kick test method to identify the proper
markings for the other two leads of each group. The two coils #3 & #6 and #3 & #8,
acting in parallel, will produce the effect of a coil positioned halfway between the
actual position of the two coils. The flux produced by #3 & #6 and #3 & #8
combined, will be perpendicular to the axis of #1 & #4 and #2 & #7. Opening and
closing a switch in this circuit will produce a kick in coils #1 & #9 and #2 & #5,
but no kick in #1 & #4 and #2 & #7.</p>
<p align="justify">Therefore, if the battery is connected from #3 & #6 and #3 & #8
as shown, opening and closing the battery circuit, the voltmeter will identify leads #1,
#4, and #9 and can be distinguished by noting the magnitude rather than the polarity. The
voltmeter can then be connected to terminal #2 for determination of the leads #5 & #7.
Leads #2 to #7 will give little or no deflection, and leads #2 to #5 will give a
substantial deflection.</p>
<p align="justify">In succession, the battery is then transferred to the corner of #1. Tie
the battery between leads #1 & #4 & #9. Making and breaking the circuit will be
perpendicular to #3 & #8 and #2 & #5, resulting in no deflection. However, there
will be a deflection from leads #2 & #7 and #3 & #6. Placing the battery next on
the #2 & #5 and #2 & #7 leads will be perpendicular to #1 & #9 and #3 & #6
leads, therefore creating no deflection. Leads #1 & #4 and #3 & #8 would then have
a deflection, thus concluding the lead testing of the nine lead delta connected motor.<b><u></p>
<p align="justify"><br>
Star Connected Motor</u>:</b></p>
<p align="justify">Mark the three leads with continuity, #7, #8, and #9. Clip the battery
to the #8 & #9 pair, clipping onto one and flashing the other. Clip the voltmeter to
each pair of leads with continuity between them, until a pair is found that produces
little to no "kick" or deflection. This pair of leads consists of the #1 &
#4 leads. Next, move the battery to the #7 & #8 combination, with the positive lead on
the #7 lead and the negative lead to be used for flashing the #8 lead. The voltmeter is so
placed on the #1 & #4 pair that an upscale deflection is observed on the
"make" of the negative #8 lead. The voltmeter positive lead is then the #1 motor
lead, and the negative voltmeter is the #4 motor lead. </p>
<p align="justify">Next, move the battery to #7 & #9 leads with the positive lead on
the #9 motor lead, and the negative to flash the #7 lead. Identification of the #3 motor
lead is then determined by an upscale kick. The positive voltmeter lead should be on this
lead, and the negative lead should be on the #6 motor lead. Shift the battery to the #8
& #9 pair, with the positive battery lead on the #8 lead and the negative used for the
flashing. An upscale kick will identify the #2 motor lead. The positive voltmeter lead
will be found on the #2 lead, and the negative voltmeter lead will be the #5 lead. This
concludes the lead testing of the nine lead star connected motor.</p>
