Two Rotor Induction Motors

Me I deployed two squirrel cage induction motors (SCIM)with

two inline speed reducers in the motorised vresion of a hydraulic press I

designed .Looking for bidders to buy off the design.

Eng. Thaddeus Ikechukwu,

Port Harcourt,Nigeria.

Are they two separate rotors, axially bolted together with separate stators? I was evolved with a similarly constructed DC motor used for pulling a heavy steel mill. It had back to back armatures with two commutators, was ± 4m in diameter and was thyristor speed controlled. I was told that the reason for this configuration was easier control of operation in different directions. How big is the motor you are talking about? Could it perhaps be for more power while keeping the kW per unit and diameter down? Because of excessive centrifugal forces bigger rotor diameters become a problem at higher speeds.

Are there motors with two rotors and no stator (with one acting as a stator for the other)? Presumably the shafts would protrude from opposite ends of the motor housing, and would have to rotate in opposite directions, and one could only produce torque relative to the torque produced at the other.

Can't the rotor of a self starting synchronous motor be regarded as a double rotor? It has in fact a set of squirrel cage bars for starting and a set of DC poles for synchronous operation, imbedded into each other, on the same shaft.

Ken, I think that if there isn't such a motor as the one you described, somebody is going to snatch up the idea and patent it! Imagine using a clutch arrangement to clamp the one or the other rotor/stator for allowing which end to rotate. The shafts will be controlled to rotate in opposite directions. (Not at the same time)