ELECTRICAL MACHINE GAS COOLING METHOD AND ELECTRICAL MACHINE Russian patent published in 2005 - IPC

FIELD: electrical and electromechanical engineering; closed-cycle cooling systems for turbogenerators and other electrical machines using fans as delivery members.

SUBSTANCE: proposed method for gas cooling of electrical machine using closed-cycle exhaust-ventilation system involves delivery of cooling gas from stator coolers and from rotor coolers through fans disposed either side of rotor barrel and through rotor ducts, whose inlets and outlets are disposed on different radii of rotor motion, over three parallel paths to rotor ducts and stator core ducts; gas heated within these ducts is conveyed to stator and rotor coolers through hot gas accumulating chamber organized in vicinity of stator end windings. In the process gas heated in rotor ducts and some portion of gas heated in stator ducts is conveyed by means of fans to stator coolers, and remaining portion of gas heated in stator ducts is passed directly to rotor coolers. For implementing this method, electrical machine is provided with cooling ducts in main area of stator core uniformly distributed over its circumference. Entrance in and exit from each duct is made on core outer surface so that they do not communicate with stator-to-rotor gap thereby eliminating intercommunication between stator and rotor cooling systems and affording uniform winding and iron temperature distribution through length and circumference of stator core. Hot gas formed in stator-to-rotor gap does not reach stator ducts which raises stator winding and iron cooling effectiveness. Proposed cooling system provides for reducing slot height and stator core outer diameter thereby enabling reduction of material input due to reduced consumption of electric steel, winding copper, and high-voltage insulating materials. Novelty is also that cooling of stator core butt-end part is organized over single-jet circuit in which gas flows over radial cooling ducts between iron stacks from stator core periphery to end windings thereby raising cooling effectiveness for stator core butt-ends and ensuring electrical machine running consuming reactive-power. Total gas flow circulating in electrical machine cools down stator end windings and its butt-end structural components which makes it possible to dispense with any additional delivery sources for cooling these components.

EFFECT: enhanced efficiency due to reduced windage loss, augmented cooling efficiency of stator core and winding, and reduced material input.

1 cl, 1 dwg