Strange Motor Wiring: 6 Motors, 200HP, 380V 50Hz

[esso]

hey guys... i have 6 motors at work, 380V, 50Hz, 200 HP. the terminals are labeled 1,2,3,7,8 and 9.
continuity test showed that 1,2,3 are connected together, and 7,8,9 are connected together. how is that possible ?? am i missing something ?? note that that is the case in all 6 motors.
thx

 

[Averagesupernova]

I am assuming this is a 1250 RPM 3 phase motor?

 

[esso]

1485 RPM , 3 phase motor

 

[SirAskalot]

Wound rotor induction motor is somthing that comes to my mind.

Does it have slip rings and brushes?

 

[I_am_learning]

How many ohms in continuity test? I would suggest doing resistivity test. Some multimeters show ohms as high as 25 as continious.

 

[Averagesupernova]

My bad, I should have taken 50 x 60 / 2 to get the synchronous RPM. Instead I took 50 x 50 / 2. If this were a high RPM motor (2970) you would only have 3 wires. Since it is a low RPM motor you have an extra set of poles and wires.

 

[esso]

around 0.5 ohm between any two connected terminals (1,2,3) or (7,8,9).
Having the extra set of poles and wires doesn't explain why are they connected.
i'm beginning to think that there's something wrong with them (they're made in the eighties after all) , but what's the odds that all 6 of them have the same problem.

 

[Averagesupernova]

So just how do you think they should be connected? I am pretty sure that the sets of 3 are connected in a delta fashion. You would naturally measure a low resistance between them as you have.