Abstract: A compact fiber laser unit includes a laser source, a laser oscillator connected to the laser source for generating an optical and a laser amplifier connected to the laser oscillator for amplifying the optical pulse produced by the laser oscillator. The laser oscillator includes a first optical fiber that connects bulk components of the laser oscillator to the laser source and the laser amplifier includes a second optical fiber that connects bulk components of the laser amplifier to the laser source. The first and second fibers are wound around a common holder in the form of a fiber tray. The fiber tray is connected to a fiber bench and the bulk components of the laser oscillator and the laser amplifier are mounted on the fiber bench.

Abstract: An engine driven air conditioner for adjusting a temperature of an inner space of a room, includes a coolant circuit having a compressor, a condenser, an expansion device and an evaporator, an engine for driving the compressor, and a control device for controlling the coolant circuit and the engine in such a manner that the engine is driven at its minimum power or at a power other than the minimum power. During operation the engine is stopped if the temperature exceeds a first set value while the engine is being driven at the minimum power, the engine is stopped if the temperature exceeds a second set value which is less than the first set value while the engine is being driven after the minimum power operation, and the engine is driven at the minimum power when the engine is re-started after a temporary stop of the engine.

Abstract: The invention relates to a speed control system for a multiple engine air conditioning system in which two or more engines are used to drive respective compressors for operation of two or more heat pump circuits. According to the invention, the engine speed control system has a negative pressure generating circuit connected in common to the intake manifolds of two or more engines.

Abstract: A starting apparatus includes an engine for driving a device such as a compressor, a starting motor by which the engine is brought into operation and a rectifier supplying a high DC voltage to the starting engine during operation thereof and supplying a low DC voltage to one or more electric components in the device while the starting motor is not in use. Thus, excess DC is prevented from being supplied to one or more components which operate under a low DC voltage, thereby preventing damage thereto.