Abstract A high speed homopolar generator is described capable of operating efficiently at rotational speeds of 90,000 rpm and above. The generator includes a smooth cylindrical rotor with axially in-line magnetic north and south poles at opposite ends of the rotor. The AC windings in the individual stator stacks are offset by 180 electrical degrees as they pass between stacks to insure that the induced voltage in the active portions of each winding are of the proper polarity. The cylindrical rotor construction minimizes windage losses and includes a straight bar of magnetic material with the circumferential interpolar space filled with a non-magnetic material. The non-magnetic material is bonded to the magnetic bar so that the resulting magnetic-nonmagnetic composite rotor is strong enough to withstand the mechanical stresses to which it is subjected at speeds in excess of 90,000 rpm. Layers of the non-magnetic material are deposited on the bar of magnetic material by a plasmaarc hot wire welding process and the assembly is then machined into the desired cylindrical shape to minimize windage. In this fashion, the geometry of the rotor is optimized, the maximum amount of axial magnetic section is obtained with the simplest rotor geometry, the requisite physical strength is obtained, while at the same time, reducing or minimizing windage at the very high velocities obtained in the machine.
A process for fabricating a solid, composite cylindrical rotor fOr a homopolar machine, comprising the steps of, a. providing a rectangular bar of magnetic material, b. bonding a mass of non-magnetic material on a pair of opposite faces of the said rectangular bar including successively depositing a plurality of layers of the non-magnetic material on each of said opposite faces to form a composite bar, c. machining the composite bar to form a composite, cylindrical rotor.
Claim 2
Dependent Claim
76 words
A process for fabricating a solid, composite cylindrical rotor fOr a homopolar machine, comprising the steps of, a. providing a rectangular bar of magnetic material, b. bonding a mass of non-magnetic material on a pair of opposite faces of the said rectangular bar including successively depositing a plurality of layers of the non-magnetic material on each of said opposite faces to form a composite bar, c. machining the composite bar to form a composite, cylindrical rotor.
Claim 3
Dependent Claim
33 words
The process for forming a composite rotor for a homopolar machine according to claim 1 wherein the plurality of layers of non-magnetic material are desposited by hot-wire plasma-arc welding of the non-magnetic material.
Claim 4
Dependent Claim
42 words
The process for fabricating a rotor for fabricating a homopolar machine according to claim 2 wherein deposition of the layers is alternated between opposite faces of the bar of magnetic material to avoid distortion of the magnetic bar due to thermal stresses.
Claim 5
Dependent Claim
27 words
The process for forming the rotor for a homopolar machine according to claim 2 including the further step of attaching a shaft to the composite cylindrical rotor.