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Identifying Unmarked 9 Lead Motors WYE Connection

Prof. Steve discusses how to identify unmarked 9 leads (WYE connection) on an electric motor.


You will Need:
  • Analog volt meter
  • 6 or 9 volt battery
  • Tape to label leads
  • Link to Augie Hand’s “Identifying Unmarked Leads”
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Prof. Steve shows how to identify unmarked 9 lead (WYE connection) on a motor. --WYE CONNECTION—


Today were going to identify the 9 lead motor if we don’t have any numbers, or let’s say the numbers 1 and 4, which are in the same phase are missing, rather than trying to figure out through hit and miss, whether were going to hit the #1 or #4 were going to be able to tell exactly which one is which. In order to do this procedure, and this procedure was written by Augie Hand, we are going to need either a 6 or a 9 volt battery and were also going to need an Analog Voltmeter. Now we can go to a demonstration on how this is actually done. First thing we’re going to do is find out whether we have the “WYE” or “Delta” configuration.

We’re going to use an analog voltmeter, first thing we need to do is identify our combinations. These two light, we’re going to check all 9. These two are going to be a pair, just going to kind of twist these together so we know what they are or that they do have continuity. Now being since we got a pair already, we know this is going to be a WYE configuration. These two numbers are going to be a pair, and there is our third pair. There’s our third pair, so this has to be a WYE configuration. We’ve got 3 leads that light together. These 3 we’re going to go ahead and label 7, 8, and 9.

This is our internal WYE connection. Next thing we’re going to do is we’re going to locate #1 and #4. We need to pay attention to which lead is our positive on our meter, and which lead is positive on the battery. To identify the #1 and #4 we’re going to connect the positive terminal to the battery to #7 and then we’re going to flash the negative to #8, in order to find #1 and #4 with an upscale deflection. We’re going to go ahead and put it on each set and flash the negative to #8 then take another set. You can see that there is very little deflection but there is a deflection there. It’s very, very minute, basically no deflection. This is our strongest deflection, so these numbers are going to be our #1 and #4. Now to determine which one is #1 and which is #4 with an upscale deflection the positive lead of the voltmeter will be on #1 and the negative will be on #4, so our positive lead is #1, we can go ahead and identify that as #1, and the negative lead of our voltmeter is going to be #4.

With 7, 8, and 9 identified and our #1 and #4 we need to identify #3 and #6. With #3 and #6 were going to take the negative side of the battery, connect it to #7, the positive side of the battery is going to be flashed to #9. We’re going to go ahead and put our voltmeter on 2 of the other pairs and flash to #9 and we do have a deflection and there we have very little or no deflection, so we’ll go back and double check that, and there we have our deflection. There we have our #3 and #6 with an upscale reading the positive lead of the voltmeter is #3, we’ve got a positive deflection so the positive lead of our meter is going to be #3, we can go ahead and identify that. The negative side of our meter is going to be #6.

The last two were going to need to find #2 and #5. In order to identify #2 and #5, the last two leads without numbers, were going to put the negative terminal of the battery on #9 and flash to #8 with our positive terminal. We have an upscale deflection so that means the positive will be #2 and our negative will be #5. Now we’ve identified all 9 leads and this motor can be safely energized, and we know that our connections are correct. This works on a Wye connected motor, the Delta connected motor which we’ve already talked about has a different procedure which we can talk about at a later time.
On behalf of York Repair and myself thank you for viewing this video. If you have any questions regarding anything seen in this video please give us a call, thank you.

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