How should customers choose diesel generator sets?

    1. Eight traps that users should pay attention to when purchasing
     1. Confusing the relationship between KVA and KW. Exaggerating the power by treating KVA as KW and selling it to customers. In fact, KVA is apparent power, and KW is effective power. The relationship between them is IKVA=0.8KW. Imported units generally use KVA to express the power unit, while domestic electrical equipment is generally expressed in KW, so when calculating power, KVA should be converted into KW at a 20% discount.
2. Not talking about the relationship between long-term (rated) power and backup power, only saying "power", and selling backup power to customers as long-term power. In fact, backup power = 1.1 x long-term power. Moreover, backup power can only be used for 1 hour in 12 hours of continuous operation.
3. The diesel engine power and the generator power are configured to be the same in order to reduce costs. In fact, the industry generally stipulates that the diesel engine power ≥ 10% of the generator power because of mechanical loss. Even worse, some companies report the diesel engine horsepower as kilowatts to users, and use diesel engines with less than the generator power to configure the unit, commonly known as: a small horse pulling a big cart, which reduces the life of the unit, frequent maintenance, and high usage fees.
4. Sell second-hand refurbished machines to customers as brand new machines, and some equip refurbished diesel engines with brand new generators and control cabinets, so that ordinary non-professional users can't tell whether it is a new machine or an old machine.
5. Only report the brand of the diesel engine or generator, not the place of origin, and do not report the brand of the unit. Such as Cummins in the United States, Volvo in Sweden, and Stanford in the United Kingdom. In fact, it is impossible for any diesel generator set to be completed independently by one company. Customers should fully understand the manufacturers and brands of the diesel engine, generator, and control cabinet of the unit in order to comprehensively evaluate the grade of the unit.
6. Sell units without protection functions (commonly known as four protections) to customers as units with complete protection functions. What's worse, they sell units with incomplete instruments and no air switches to customers. In fact, the industry generally stipulates that units above 10KW must be equipped with full instruments (commonly known as five meters) and air switches; large units and automated units must have self-four protection functions.
7. Do not talk about the brand grade of diesel engines and generators, control system configuration, and after-sales service, but only talk about price and delivery time. Some also use non-power station-specific oil engines, such as marine diesel engines and automotive diesel engines, for generator sets. The quality of the unit's terminal product - electricity (voltage and frequency) cannot be guaranteed. Units with too low prices generally have problems, commonly known as: only buy the wrong one, not sell the wrong one!
8. Do not talk about the random accessories, such as whether it comes with a muffler, fuel tank, oil pipeline, what grade of battery, how large the battery capacity, how many batteries, etc. In fact, these accessories are very important and must be stated in the contract. What's worse, some even don't bring a water tank fan, and let customers build an open pool by themselves.

     II. Purchase of Generator Sets
When purchasing diesel generator sets, you should fully consider the comprehensive performance and economic indicators of the diesel generator sets, the supplier's professionalism, geographical location and actual professionalism, and whether the supplier has after-sales service means, such as emergency repair vehicles, special machinery, etc. Then consider whether the power of the selected unit matches the power of the power load. Generally, it is better to select the power of the unit based on: the rated power of the unit x 0.8 = the power of the power equipment. If there are large and medium-sized motors, 2-5 times the starting current must also be considered. If the unit is mainly used to charge UPS, a professional consultation must be made based on the actual situation of the UPS, and then the rated power of the generator is determined.

     III. Installation of the Generator Set
Before using the diesel generator set, it should be installed and connected. When installing a diesel generator set, the following matters should be noted:
1. The installation site needs to be well ventilated, the generator end should have sufficient air inlets, and the diesel engine end should have good air outlets. The air outlet area should be more than 1.5 times larger than the water tank area.
2. The area around the installation site should be kept clean, and avoid placing items that can produce corrosive gases and steam such as acid and alkaline nearby. Fire extinguishing equipment should be configured if conditions permit.
3. If used indoors, the exhaust pipe must be connected to the outdoors, and the pipe diameter must be ≥ the smoke outlet pipe diameter of the muffler. The elbows of the connected pipe should not exceed 3 to ensure smooth exhaust, and the pipe should be tilted downward by 5-10 degrees to avoid rainwater injection; if the exhaust pipe is installed vertically upward, a rain cover must be installed.
4. When the foundation is made of concrete, its level must be measured with a level ruler during installation to fix the unit on a horizontal foundation. There should be a special shock-proof pad or foot bolts between the unit and the foundation.
5. The shell of the unit must have reliable protective grounding. For generators that need to have direct neutral point grounding, the neutral point grounding must be carried out by professionals and equipped with lightning protection devices. It is strictly forbidden to use the grounding device of the mains for direct neutral point grounding.
6. The two-way switch between the generator and the mains must be very reliable to prevent reverse power supply. The wiring reliability of the two-way switch must be inspected and approved by the local power supply department.
7. The wiring of the starting battery must be firm

     IV. Unit matching
In addition to the matching parts provided by the supplier, there are also some optional parts for diesel generators, such as fuel tanks, mains chargers, fuel oil pipelines, etc. It is very necessary to know how to choose these additional parts. First of all, the fuel storage capacity of the unit's fuel tank should be able to provide the unit with full load continuous operation for more than 8 hours. Try to avoid refueling the tank when the unit is running. Secondly, the AC charger should be a special charger with floating charge to ensure that the battery can drive the unit at any time. The coolant should be rust-proof, antifreeze and anti-boiling liquid as much as possible. Special diesel engine oil above CD level must be used.

     V. Importance of AC Switch
There are two types of AC switch: manual and automatic (ATS for short). If your diesel generator is used as a backup power source, a AC switch must be installed at the input point of the power supply. It is strictly forbidden to input self-supplied power to the load by temporary wiring and memory operation. Because once the self-supplied power source is connected to the grid without authorization (referred to as reverse power supply), it will cause serious consequences such as casualties and equipment damage. Whether the switch is installed correctly or not, it must be inspected and approved by the local power supply department before it can be put into use.