Emergency generators are generally recommended to use high-speed, turbocharged, low fuel consumption generator sets of the same capacity. High-speed turbocharged diesel engines have larger single-unit capacity and occupy less space; diesel engines are selected with electronic or hydraulic speed control devices, providing better speed regulation performance; generators should use synchronous motors with brushless excitation or compound excitation devices, ensuring reliability, low failure rate, and easier maintenance and repair; when the capacity of a single air conditioner or motor in the primary load is large, generator sets with third harmonic excitation should be used; the unit is installed on a common chassis equipped with shock absorbers; the exhaust pipe outlet should be fitted with a silencer to reduce noise impact on the surrounding environment. (1) Capacity determination: Emergency generator sets are used for emergency purposes, usually in standby emergency start mode, with short continuous running time, generally not exceeding 8 hours, so capacity can be determined based on "standby power." According to the sum of the primary load capacity (excluding standby capacity), considering the corrected unit capacity, and meeting the starting requirements of the largest motor in the primary load, the capacity of the emergency diesel generator set is determined accordingly. Emergency generators generally use three-phase AC synchronous generators with a rated output voltage of 400V. (2) Number of units determination: Generally, one unit is selected with automation, speed of 1000–1500 rpm, brushless excitation, 400/230V, three-phase four-wire with control panel, charging and discharging equipment, and a common chassis. A common chassis with a daily-use fuel tank can be requested to reduce piping and space occupation. Additionally, for reliability, two units can be connected in parallel for power supply. The number of emergency generator units supplied generally should not exceed three. When multiple units are selected, the units should preferably be of the same model and capacity, with similar voltage and speed regulation characteristics, and use the same type of fuel to facilitate maintenance and shared spare parts.