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How to Choose an Emergency Generator Set?

Dec. 17, 2021

The emergency generator set is mainly used in important places. In an emergency or accident, the power will be cut off instantly, and the emergency generator set can quickly restore and extend the power supply time. This type of electrical load is called a primary load. In addition to generators, equipment, instruments and computer systems that have strict requirements for power outage time should also be provided with batteries or UPS for power supply.


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Determination of emergency generating set capacity: the rated capacity of emergency generating set is the 12h calibrated capacity after atmospheric correction, and its capacity should be able to meet the total calculated emergency power load, and according to the generator capacity, it can meet the rated capacity of a single motor in the first load. The start-up requirements are verified. Emergency generators generally use three-phase AC and synchronous generators with a calibrated output voltage of 400V


Determination of the number of emergency generator sets: When there are multiple generator sets in standby, generally only one emergency generator set is installed. For reliability considerations, two generator sets can also be selected for power supply in parallel. Generally, the number of emergency generating sets should not exceed 3. When multiple generator sets are selected, the generator sets should try to select complete sets of equipment with the same model and capacity, and similar pressure and speed regulation characteristics, and the nature of the fuel used should be the same for maintenance and sharing of spare parts. When there are two generator sets for emergency use, the self-starting device should enable the two generator sets to be mutually backup, that is, after the mains power failure and power failure are confirmed after a delay, a self-starting command will be issued. If the first generator set has 3 consecutive If the second self-starting fails, an alarm signal should be issued and the second generator set should be started automatically.


The choice of emergency generator set: The emergency generator set should be high-speed, pressurized, low fuel consumption, and the same capacity generator set. High-speed supercharged diesel engines have a large single engine capacity and occupy a small space. Diesel engines are equipped with electronic or hydraulic speed regulation devices, which have better speed regulation performance; generators should use synchronous motors equipped with brushless excitation or phase compound excitation devices for more reliable performance and failure Low rate and convenient maintenance and repair; when the capacity of a single air conditioner or motor in the primary load is large, the generator set with third harmonic excitation should be selected; the generator is assembled on a shared chassis with shock absorbers; A muffler should be installed at the outlet of the smoke pipe to reduce the impact of noise on the surrounding environment.


Control of emergency generating set: The control of emergency generating set shall have quick self-starting and automatic switching devices. When the main power supply fails and the power is cut off, the emergency generator set should be able to quickly start and restore the power supply. The allowable power-off time for the first-class load ranges from ten seconds to several tens of seconds, which should be determined according to the specific conditions. When the main power supply of an important project is cut off, a certain time of 3-5S should be passed first to avoid the instantaneous voltage drop and the time for the city grid to close or the standby power supply is automatically turned on, and then issue the instruction to start the emergency generator set . It takes a certain period of time from the time the command is issued, the generator set starts to start, and the speed rises to reach full load. Generally, large and medium-sized diesel engines also require pre-lubrication and warm-up processes, so that the oil pressure, oil temperature, cooling and water temperature during emergency loading meet the specifications of the factory's technical conditions; the pre-lubrication and warm-up processes can be carried out in advance according to different conditions. For example, military communications, important foreign affairs activities in large hotels, large-scale mass activities at night in public buildings, and important surgical operations in hospitals. Emergency generator sets should be pre-lubricated and warmed up so that they can be started quickly at any time to minimize faults and power failures. time.


After the emergency generator set is put into operation, in order to reduce the mechanical and current impact when the load is suddenly applied, the emergency load should be increased in stages according to the time interval when the power supply requirements are met. According to national standards and national military standards, the first allowable load capacity of an automated generator set after a successful start is as follows: For those with a nominal power of no more than 250KW, the first allowable load is no less than 50% of the nominal load; for those with a nominal power greater than 250KW, press Regulations on technical conditions of factory products. If the requirements for the instantaneous voltage drop and transition process are not strict, the general generator set's sudden increase or unloading of the load should not exceed 70% of the generator set's rated capacity.


Starlight Power was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. If you want get more information, please feel free to send email to sales@dieselgeneratortech.com we will pay highly attention on your question.

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