Chris, what willem stated is an important lesson when modernising or reparing ac motors as its very common to have to test a burnt out motor or to test and install a repaired motor that the winders have forgotten to number the leads. Remember most of the time with a 3 ph motor they will be marked either 123/u1,v1,w1 and 456/u2,v2,w2. If you get a 3 ph motor with no markings remember that the're many ways to wire them but essentially you test between all leads for a cct. I bet it would be 1 to 4, 2 to 5 and 3 to 6 as the 3 windings of the slow speed and the same for the fast speed. You can also identify the fast and slow windings like willem said as the higher resistance will be the slow speed windings and vice versa. Just to note that most modern 2 speed ac motors wont have 12 wires as they would have an internal star/ delta connection and all that would be at the terminals would be the three phase slow and fast speed connections.
Last edited by uppo72; 08/01/13 01:14 AM.
