Prof. Steve discusses how to identify unmarked 9 lead (Delta connection) on a motor. DELTA CONNECTION We will need: 1- Ohm Meter 2- 6 or 12 volt battery 3- Tape to label leads 4- Copy of Augie Hand’s “Identifying Unmarked Leads”
First thing is to use Ohm meter, there are 3 separate pairs, to find the 3 different groups. Normally, I use a piece of tape to mark each one of the groups, and when we have the right combination were going to end up having the full voltage across 2 leads and then go from 1 lead to the other, to the center, and we will have half the voltage across each one of those leads. The one that gives us the low voltage or the half voltage across each group will be labeled 1, 2, or 3. Then we will connect #1, 4, and 9, 4 and 9 are connected to the battery terminal, 1 is flashed with the other battery terminal. A strong deflection will occur across 2 and 7, 3 and 6, little or no deflection across 2 and 5 and 3 and 8. Leads 5, 6, 7, and 8 can now be labeled. Were going to connect the leads 5 and 7 to the battery then flash across 2, leads 1 and 4 will show a strong deflection, leads 1 and 9 will have little or no deflection. So leads 4 and 9 can now be labeled. First thing we will do is identify our 3 circuits, look for continuity between 3 wires.