Coolant pump system for variable speed generators

Claim 1

A coolant pump system for an oil cooled generator, having a generator housing and a generator rotor mounted for rotation at a variable speed with respect to said housing, said pump system comprising: a variable displacement pump mounted within said generator housing and mechanically coupled to said generator rotor such that said pump is driven at a speed proportional to the rotational speed of said generator rotor, said pump including a pump rotor mounted for rotation on an axis which is fixed with respect to said generator housing, a plurality of sliding vanes extending radially outward from said pump rotor, a pump stator defining a generally cylindrical opening for receiving said pump rotor, said opening having an inlet port for receiving coolant from an external hydraulic circuit and an outlet port for delivering coolant to said external hydraulic circuit, said pump stator being moveable with respect to said axis in first and second directions perpendicular to said axis, such that movement of said pump stator in said first direction increases the displacement of said pump and movement of said pump stator in said second direction decreases the displacement of said pump; means for applying a first force to said pump stator in said first direction, thereby tending to increase the displacement of said pump; a plurality of coolant passages in said generator housing connected to receive coolant from said pump; means for applying a second force to said pump stator in said second direction in response to a pressure of said coolant in one of said coolant passages, thereby tending to reduce the displacement of said pump as said pressure increases; means for producing a control signal which is a function of the electrical load on the generator; and means for applying a third force to said pump stator in said second direction in response to said control signal, thereby further tending to reduce the displacement of said pump as the electrical load on said generator decreases.

Claim 11

A method of controlling the flow of cooling oil in a variable speed, oil cooled generator comprising the steps of: providing a variable displacement pump mounted within a housing of a generator, said pump being mechanically coupled to a rotor of said generator such that said pump is driven at a speed proportional to the rotational speed of said generator rotor, said pump including a pump rotor mounted for rotation on an axis which is fixed with respect to said generator housing, a plurality of sliding vanes extending radially outward from said pump rotor, a pump stator defining a generally cylindrical opening for receiving said pump rotor, said opening having an inlet port for receiving coolant from an external hydraulic circuit and an outlet port for delivering coolant to said external hydraulic circuit, said pump stator being moveable with respect to said axis in first and second directions perpendicular to said axis, such that movement of said pump stator in said first direction increases the displacement of said pump and movement of said pump stator in said second direction decreases the displacement of said pump; applying a first force to said pump stator, said first force tending to move said pump stator in said first direction, thereby increasing the displacement of said pump; applying a second force to said pump stator in said second direction in response to a pressure of said coolant in one of a plurality of coolant passages in said generator housing, said second force tending to move said pump stator in said second direction, thereby reducing the displacement of said pump as said pressure increases; producing a control signal proportional to an electrical load on the generator; and applying a third force to said pump stator in said second direction in response to said control signal, said third force tending to move said pump stator in said second direction, thereby further reducing the displacement of said pump as the electrical load on the generator decreases.

Claim 12

A method of controlling the flow of cooling oil in a variable speed, oil cooled generator comprising the steps of: providing a variable displacement pump mounted within a housing of a generator, said pump being mechanically coupled to a rotor of said generator such that said pump is driven at a speed proportional to the rotational speed of said generator rotor, said pump including a pump rotor mounted for rotation on an axis which is fixed with respect to said generator housing, a plurality of sliding vanes extending radially outward from said pump rotor, a pump stator defining a generally cylindrical opening for receiving said pump rotor, said opening having an inlet port for receiving coolant from an external hydraulic circuit and an outlet port for delivering coolant to said external hydraulic circuit, said pump stator being moveable with respect to said axis in first and second directions perpendicular to said axis, such that movement of said pump stator in said first direction increases the displacement of said pump and movement of said pump stator in said second direction decreases the displacement of said pump; applying a first force to said pump stator, said first force tending to move said pump stator in said first direction, thereby increasing the displacement of said pump; applying a second force to said pump stator in said second direction in response to a pressure of said coolant in one of a plurality of coolant passages in said generator housing, said second force tending to move said pump stator in said second direction, thereby reducing the displacement of said pump as said pressure increases; producing a control signal proportional to an electrical load on the generator; and applying a third force to said pump stator in said second direction in response to said control signal, said third force tending to move said pump stator in said second direction, thereby further reducing the displacement of said pump as the electrical load on the generator decreases.