Yanmar eG55N

The drive is a single-cylinder diesel engine of 435 cm³ displacement, air-cooled by a flywheel fan rather than a water circuit. At 50 Hz the engine runs at 3,000 rpm and delivers 4.5 kW continuous output, or 5.1 kVA peak, at 220, 230 or 240 V; at 60 Hz speed rises to 3,600 rpm and output to 5.2 kW continuous, or 5.8 kVA peak, at 220 V or 110/220 V. The tank holds 14.5 litres, the unit weighs 171 kg, and the sound level is 72 dB(A) at full load and 50 Hz, or 73 dB at 60 Hz, both measured at 7 m.

The ability to switch between 50 and 60 Hz makes the eG55N usable for export to countries with different grid frequencies, from Europe's 230 V/50 Hz to markets running 110/220 V at 60 Hz. As a single-phase set it is designed to power lighting, tools and small pumps on construction sites and to serve as an emergency power source, not to drive large three-phase loads. The air-cooled design without a water circuit makes the set frost-resistant and reduces maintenance compared with water-cooled versions.

When buying one used, check the flywheel fan and cooling fins for contamination, since a clogged air-cooling system quickly overheats the single cylinder. It is also worth checking running hours, the condition of the injector and the generator's insulation values, as well as the tank for corrosion and water in the diesel, a common problem on sets that have stood outdoors for long periods.