초록 ▼

An auxiliary power unit ("APU") system and methods used to bring such system on-line and off-line are disclosed. An APU generator forming part of an APU system, is brought "on-line" smoothly in order to replace a primary generator operating at a steady-state rotational speed that is interconnected w

An auxiliary power unit ("APU") system and methods used to bring such system on-line and off-line are disclosed. An APU generator forming part of an APU system, is brought "on-line" smoothly in order to replace a primary generator operating at a steady-state rotational speed that is interconnected with a load. A controller forming part of the APU system controls rotational speed of the APU and thereby the generator so that it approaches a rotational speed beneath the steady-state rotational speed of the primary generator. The controller then connects the APU generator to the load and the primary generator. This causes the APU generator to motor at the steady-state rotational speed dictated by the primary generator. Thereafter, the controller may increase rotational speed of the APU generator until it provides power to the load and the primary generator may be disconnected from the load. Advantageously, by allowing the APU generator to motor at the steady-state rotational speed of the primary generator, no high impact shocks are imparted to the generator. Moreover, preferably, the APU generator is coupled to an APU by an over-running clutch so that no torque is transferred from the generator to the APU. The primary generator may be re-connected to the electrical load, powered by the APU generator by first adjusting the rotational speed of the APU generator to a set-point beneath the steady-state rotational speed of the primary generator. Then the primary generator operating at the steady-state rotational speed may be interconnected to the load and the APU generator. This again causes the APU generator to motor at the steady-state rotational speed. Now, as the APU generator is no longer providing power to the load, it may be disconnected from the load.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method of operating an auxiliary power unit ("APU") generator forming part of an APU system, to replace a primary generator operating at a steady-state rotational speed interconnected with a load, said method comprising in sequence, the steps of:a. adjusting rotationa

[ What is claimed is:] [1.]1. A method of operating an auxiliary power unit ("APU") generator forming part of an APU system, to replace a primary generator operating at a steady-state rotational speed interconnected with a load, said method comprising in sequence, the steps of:a. adjusting rotational speed of said APU generator, until said APU generator speed is beneath said steady-state rotational speed;b. interconnecting said APU generator to said load and said primary generator, thereby causing said APU generator to motor at said steady-state rotational speed;c. increasing said rotational speed of said APU generator, until said generator provides power to said load; andd. disconnecting said primary generator from said load.