Hosem generator sets are primarily used in critical environments to quickly restore power and extend supply time during a power outage or emergency. Such power loads are referred to as primary loads. For systems like communication equipment, instruments, and computer systems that have strict requirements for uninterrupted power, in addition to a generator set, a backup battery or UPS should also be installed.

The operation of a Hosem generator set has two key characteristics: 

1. Emergency Use: The continuous operation time is usually short, generally needing to run for only a few hours (≤12h).

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2. Standby Use: The emergency generator set remains in a standby mode most of the time, only starting up when the main power source fails. Once the main power source is restored, the generator set will automatically switch off.

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Determining the Capacity of Diesel Generator Sets

The rated capacity of an emergency diesel generator set should be the 12-hour rated capacity after environmental corrections (such as altitude, atmospheric pressure, and air humidity). This capacity should meet the total calculated emergency power load, and it must be verified that the generator capacity can handle the startup of the largest single motor in the primary load. Emergency generators typically use three-phase AC synchronous generators with a rated output voltage of 400V.

Determining the Number of Diesel Generator Sets

When there are multiple backup generator sets, usually only one emergency diesel generator set is installed. For reliability, two units can be selected to operate in parallel. The number of generator sets used for emergency power supply should not exceed three. When multiple diesel generators are selected, they should ideally be of the same model and capacity, with similar voltage and speed regulation characteristics. The fuel type should be consistent to facilitate maintenance, repair, and spare parts sharing. If there are two emergency generator sets, the automatic startup system should ensure mutual backup. If the first unit fails to start after three attempts, an alarm signal should be sent, and the second unit should automatically start.

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Selecting the Characteristics of Diesel Generator Sets

For emergency use, it's advisable to select high-speed, turbocharged, low fuel consumption, high-reliability diesel generator sets of the same capacity. High-speed turbocharged diesel engines have larger single-unit capacities and take up less space. Diesel engines equipped with electronic or hydraulic speed regulators are preferable due to their superior speed regulation performance. The generator should preferably be a brushless excitation synchronous motor, which is reliable, has a low failure rate, and is easier to maintain. The generator set should be mounted on a common chassis equipped with vibration dampers. It is also advisable to install a muffler at the exhaust outlet to reduce noise pollution.

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Control of Diesel Generator Sets

Emergency diesel generator sets should be equipped with a fast automatic startup and connection system. When the main power source fails, the emergency generator should automatically start quickly and restore power. The allowable power outage time for primary loads typically ranges from several seconds to tens of seconds, depending on specific circumstances. In the event of a main power failure in critical projects, there should first be a confirmation period of 3 to 5 seconds to avoid momentary voltage drops and allow time for the main power grid or backup power to be automatically switched on. Only after this should the command to start the emergency generator be issued. From the time the command is given, the generator set begins to start, accelerate, and reach a load-bearing speed, which requires some time. Medium to large diesel generator sets generally require a pre-lubrication and warming-up process to ensure that when the system is fully loaded, the oil pressure, oil temperature, and coolant temperature meet the technical specifications of the product. The pre-lubrication and warming-up process can be carried out in advance, depending on the situation. For example, emergency generator sets for postal and military communications, large hotels hosting important foreign events, public buildings holding large public activities at night, or hospitals performing critical surgeries should always be in a pre-lubricated and warmed-up state to enable quick startup and minimize power outage time.