Identify Unmarked Leads in a 9 Lead WYE Connected Motor

Walter Resendes

Walter Resendes

If you have ever tried to wire up a motor only to find that the motor winding leads in the motor have lost their identification number markings, you know how frustrating that can be. In this blog post article we will show you how to identify the leads easily. All you will need is a large flashlight battery, some wire leads, and some patience.

  1. Find (1) set of 3

  2. Find (3) sets of 2

  3. Mark the (1) set of 3 as 7, 8, and 9

  4. Connect a large 9 volt DC battery -dc terminal to 8 and flash the +dc terminal to 9.

    1. Test between all (3) sets of two with an analog millivoltmeter.

    2. The sets that will become 3 & 6 and 2 & 5 will show a large inflection in the needle. But 1 & 4 will be a very small inflection. Find the small inflection set and these will be 1 & 4.

  5. Now we need to determine which is 1 and which is 4.

6. Connect the -dc lead to terminal 7 and the +dc lead to terminal 9

  1. Flash the + to Terminal 9 and the meter should deflect.

  2. When the meter positive is on the 1 and the meter common is on the 4, the meter will deflect to the right (positive).

  3. When this is the case, mark the wire connected to the positive lead (1) and the wire connected to the negative lead (4).

Identifying motor leads 1 and 4
  1. Now find set 3 & 6 by connecting the battery between terminals 7 and 8.
    1. Flash the battery lead and measure the two remaining unidentified sets.

    2. The set showing almost no deflection is winding 3 & 6.

  1. Now find for which is 3 and which is 6.

    1. Connect the -dc lead to terminal 9 and the +dc lead to terminal 8

 2. Flash the + to Terminal 8 and the meter should deflect

 3. When the meter positive is on the 3 and the meter common is on the 6, the meter will deflect to the right (positive).

 4. When this is the case, mark the wire connected to the positive lead (3) and the wire connected to the negative lead (6).

  1. Now find set 2 & 5 by connecting the battery between terminals 7 and 9.

    1. Flash the battery lead and measure the two remaining unidentified sets.

    2. The set showing almost no deflection is winding 3 & 6.

  2. Now find for which is 2 and which is 5.

    1. Connect the -dc lead to terminal 8 and the +dc lead to terminal 7

 2. Flash the + to Terminal 7 and the meter should deflect.

 3. When the meter positive is on the 2 and the meter common is on the 5, the meter will deflect to the right (positive).

 4. When this is the case, mark the wire connected to the positive lead (2) and the wire connected to the negative lead (5

Identifying motor leads 3 and 6

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