A diesel generator is composed of a diesel engine and an alternator or an electrical generator, which converts the power created by the engine (expressed in RPM, revolutions per minute) into the required voltage for homes, industry and remote work sites. The need for power for homes and sites, which are not connected, to a power grid is a growing need throughout the world. Every diesel generator is rated at how many kilowatts of power it produces. If the home or ranch requires 22 kW to 25 kW then the sized generator should be at least a 30kW. When you decide to provide power through diesel generators then you should consider whether you need a backup. The power of the generator is rated at 50% engine speed. The 30 kW diesel generator actually operates safely at 25 kW at 1800 rpm for prolonged periods of time. Other considerations in selecting a power generator involve selecting one that is a four-cycle, water-cooled industrial diesel generator.
A water-cooled generator operates more quietly than an air-cooled and it lasts longer. There are two electrical systems involved with a diesel generator, the DC (direct current) and the AC (alternating current) systems.
Then measure the voltage with the engine running at a fast idle. The resting voltage should be close to 12.6 volts and the operating voltage generally ranges 13.2 to 14.2 volts at the battery. You can also measure the output voltage at the alternator and it should measure with in 0.1 volts of the battery voltage. DON'T EVER DISCONNECT A BATTERY CABLE IF THE ENGINE IS RUNNING.
Disconnecting a battery cable with the engine running will most likely damage your voltage regulator, engine management computer and other components.