A high efficiency steam engine or steam expander includes a cylinder, cylinder head and piston in which cylinder clearance volume is zero or nearly zero together with a negligible amount of compression such that any pressure in the cylinder clearance volume just before the power stroke is as low as ambient pressure or condenser pressure to provide superior thermal efficiency in a compact compound engine having a high pressure expansion chamber within the piston and low pressure chamber in the cylinder. The inlet valve is opened slightly by piston movement and a steam assist force then drives it to its fully open position. Steam passes from the high pressure chamber to the low pressure chamber through a transfer valve located in the head of the piston and steam is released through an automatic exhaust valve in the cylinder head.

A hydraulic pressure amplifier arrangement (1) is described comprising a supply port (A1), a pressure outlet (A2) connected to the supply port via check valve means (3), a tank port (B1), an intensifier section (5) having a high pressure piston (6) in a high pressure cylinder (7) which is connected to the pressure outlet (A2), a low pressure piston (8) in a low pressure cylinder (9) and connected to the high pressure piston (6), an intermediate space (11) between the high pressure piston (6) and the low pressure piston (8), a control valve (12) controlling a pressure in the low pressure cylinder (9), and a feeder arrangement of the intensifier section (5) including an input connection (19) connected to the supply port (A1) and a return connection (20) connected to the tank port (B1). Such a pressure amplifier arrangement should have a simple construction. To this end the feeder arrangement (19, 20) comprises throttling means (21).

An apparatus and method for a generator assembly for a drive train such as a rotatable turbine engine assembly. The generator assembly includes at least first and second generators mechanically coupled to the drive train. First and second dampers are operably coupled to the first and second generators, respectively, to selectively damp the first and second generators. Damping the first and second generators can reduce or eliminate both common mode and differential mode torsional oscillations from the generators to the drive train.

An apparatus and method for a generator assembly for a drive train such as a rotatable turbine engine assembly. The generator assembly includes at least first and second generators mechanically coupled to the drive train. First and second dampers are operably coupled to the first and second generators, respectively, to selectively damp the first and second generators. Damping the first and second generators can reduce or eliminate both common mode and differential mode torsional oscillations from the generators to the drive train.

An apparatus and method for a generator assembly for a drive train such as a rotatable turbine engine assembly. The generator assembly includes at least first and second generators mechanically coupled to the drive train. First and second dampers are operably coupled to the first and second generators, respectively, to selectively damp the first and second generators. Damping the first and second generators can reduce or eliminate both common mode and differential mode torsional oscillations from the generators to the drive train.