How does one calculate the stator (or rotor) phase winding resistance (NOT impedance) of an AC 3 phase motor?
If you mean the static resistance for the stator you can simply connect the multimeter between 2 phases and arrive at the phase resistance. Usually motors windings are delta connected. You multimeter reading is 2/3x phase resistance.As for the rotor a squirrel gauge motor has no rotor windings and slip ring motors have windings connected to slip rings. In the second case apply the same principle if you know whether the windings are star or delta connected. For complete determination of the equivalent equivalent circuit conduct the no-load and blocked rotor tests. Refer a standard book on electric machines for eg Fitzgerald, Umans Kingsley
Firstly, we have to establish if this is single speed, or two speed? You have said it is a squirrel cage motor, therefore can assume to be an induction motor. Because the starter has 3 contactors, you cannot assume it is a Star/Delta started motor, even if one contactor has a star connection. A 3 phase induction motor, with, or without a star/delta starter should never have any resistance between windings if all external connections are disconnected, which you obviously appreciate. There does exist a type of motor called a tap wound, or Dahlander motor. This is a 2 speed motor with 1 x 3 phase winding. The windings are connected internally, using 3 contactors to give a pole change in ratio 2:1 using delta and star/star (Double star) configurations. Afraid not enough information is supplied, however if it is a single speed 3 phase induction motor, you have a problem with the motor, sorry. Try the site below for winding connections, I have eventually found. Good luck Chuck.
