Turbine-electric transmission enters a turbine, where it expands down to the exhaust pressure, producing a shaft work output in the process. The exhaust is fed into the power turbine used to power an output shaft for whatever desired application. The power turbine is also connected to the electric generator, which converts mechanical energy into electrical energy. The electric generator driven by the power turbine charges the battery needed in order to drive the motor that supplies compressed air into the combustor. During cruise speed the electric motor does not have to be functioning, only the gas turbine engine is required to continue
Potential energy change in the potential energy associated with the force. The negative sign provides the convention that work done against a force field increases potential energy, while work done by the force field decreases potential energy. Common notations for potential energy are "PE", "U", "V", and "E". Potential energy is the energy by virtue of an object's position relative to other objects. Potential energy is often associated with restoring forces such as a spring or the force of gravity. The action of stretching a spring or lifting a mass is performed by an external force that works against the force field