The calculation formula of power matching of diesel generator set is given

The calculation formula of power matching of diesel generator set is given

1. Several factors should be considered when selecting the unit, including mechanical and electrical performance, unit use, load capacity and variation range, unit operating environment conditions (including altitude, climate conditions, noise), automation function, etc, Therefore, different uses of diesel generator set requirements are different
2. The selection of common diesel generator set. The common generator set has a long continuous working time, the load curve changes greatly, the selection of unit capacity, number and type, and the control mode of the unit are different from the emergency unit. (1) the determination of capacity: according to the long-term continuous operation output power of the unit, it can meet the selection of the maximum calculated load of the whole project, The continuous output power of diesel engine is generally 0.9 times of the rated power. (2) the number of diesel engines is generally more than 2 to ensure the continuity of power supply and adapt to the change of power load curve, The best economic operation state of diesel engine is between 75% - 90% of rated power. In order to ensure the continuity of power supply, the common unit itself should be considered to set up standby unit. (3) determination of speed: Generally speaking, high-speed unit with speed of 1000-1500 RPM should be selected for civil use, (4) determination of voltage: the determination of output voltage of generator is the same as that of emergency generator set, generally 400V. High voltage generator set can be selected for projects with large power consumption and long transmission distance
3. Selection of standby diesel generator set. When the calculated load multiplied by the demand factor is less than the capacity of the emergency diesel generator set, the standby factor is considered as 1.2, that is, 1.2 times of the calculated capacity is less than the capacity of the emergency diesel generator set. After the power failure, the emergency generator set supplies power to the load, When the calculated load multiplied by the demand factor is greater than the capacity of a single emergency diesel generator set, two automatic generator sets with the same model, capacity and similar characteristics of voltage regulation and speed regulation can be selected. After the power failure, one or two of them will supply power to the domestic and commercial power; when the power failure occurs and a fire occurs, the two units will supply power to the fire load to facilitate fire fighting
4. Selection of emergency diesel generator. Generally, high speed, supercharged, low fuel consumption and the same capacity diesel generator set should be selected for emergency diesel generator. High speed supercharged diesel engine has larger capacity and occupies less space; electronic or hydraulic speed regulating device is selected for diesel engine with better speed regulating performance; synchronous motor with brushless excitation or phase compound excitation device is selected for generator with more reliable operation, When the capacity of a single air conditioner or motor is large in the first level load, the generator set with third harmonic excitation should be selected; the generator should be assembled on the common chassis with shock absorber; the exhaust pipe outlet should be equipped with muffler to reduce the impact of noise on the surrounding environment. (1) determination of capacity: emergency diesel generator set is used for emergency, It is often in standby emergency starting state, and the continuous operation time is not long, generally not more than 8h. Therefore, the capacity can be determined according to the "standby power". According to the sum of the capacity of the first level load (excluding the standby capacity), the modified unit capacity can be considered, and can meet the starting requirements of the largest motor in the first level load, According to this, the capacity of the emergency diesel generator set can be determined. Generally, the three-phase AC synchronous generator is selected, and its rated output voltage is 400V. (2) the determination of the number of emergency generators: generally, a generator set with automation, rotating speed of 1000-1500 rpm, brushless excitation, 400 / 230V, three-phase four wire control panel, charging and discharging equipment and common chassis is selected, In addition, considering the reliability, two units can be used in parallel for power supply. Generally, the number of emergency generating units should not exceed three. When multiple units are selected, complete sets of equipment with the same model and capacity and similar characteristics of pressure regulation and speed regulation should be selected as far as possible, and the properties of fuel used should be consistent, so as to facilitate maintenance and share spare parts
5. There are three ways to start the diesel engine: 1. Manual starting; 2. Electric starting; 3. Compressed air starting. In high-rise buildings, electric starting should be adopted to avoid compressed air starting. In a class of high-rise buildings, diesel generator set with self starting device must be selected. Once the power supply of the city network is interrupted, the diesel generator set with self starting device should be selected, The power supply must be within 15 seconds (30 seconds as required by the high-rise code). In class II high-rise buildings, when conditions permit, the unit with self starting device should also be used, and when it is difficult, the manual starting device can also be used
6. When selecting the capacity of diesel generator set and three-phase motor, it is suggested to consider the safety factor of 1.5, i.e. 1.5 times of motor capacity (soft start mode is necessary)
7. Pay attention to the relationship between rated power and backup power, and the relationship between KVA and kW. Some manufacturers in the market only say a "power", and introduce and sell the unit as the rated power. In fact, backup power = 1.1 x rated power. Moreover, backup power can only be used for one hour in 12 hours of continuous operation. In China, the rated power is generally used to identify the diesel generator set, In the world, the standby power is used to identify. KVA is apparent power and kW is effective power. The relationship between them is ikva = 0.8kw. The power unit of imported units is generally expressed in KVA, while that of domestic electrical equipment is generally expressed in kW
8. Recognize the brand of the unit. Generally, imported generator sets are assembled machines. At present, domestic generator sets are integrated (that is, generator and engine are the same brand), and their performance is the same as some imported units, and the price is cheap. Therefore, when purchasing, you should fully understand the brand of each component of the unit (some manufacturers only report the brand of diesel engine or generator, but not the origin), Only when the brand of the unit is not reported can the grade of the unit be evaluated comprehensively

1. According to the instructions, how many joules of electric energy is stored in the battery
2. If the average working current of the battery is 0.03A, how many hours can it be used at most
(rechargeable battery, standard charge)
rechargeable
1.2V 600mA·h
standardcharce
15h 60mA

1. According to the instructions, how many joules of electric energy is stored in the battery
t=W/(UI)
=(2592J)/[(1.2V)×(0.03A)]
=72000s
=20h

6X + 3 = 9 to solve the equation

6x+3=9
6x=9-3
6x=6
x=6/6
x=1

The n-dimensional vector group A1 A2 ···· am is set. It is proved that if M > N, then A1 A2 ···· am is linearly correlated
It's hard to organize language

Knowledge points:
The necessary and sufficient condition for the linear correlation of A1 A2 ···· am is that the homogeneous linear equations (A1 A2 ···· AM) x = 0 have nonzero solutions
Because R (A1, A2 ···· AM)

The third power of a is the second power of a * the x power of a = the 24th power of A

﹙a³﹚²×a^x=a^24
a^x=a^18
x=18

1. In the plane rectangular coordinate system, the set C = {(x, y) | y = x} represents the straight line y = X. from this point of view, the set D = {(x, y) | 2x-y = 1 x + 4Y = 5
1. In the plane rectangular coordinate system, the set C = {(x, y) | y = x} represents the straight line y = X. from this point of view, what does the set D = {(x, y) | 2x-y = 1 x + 4Y = 5) represent? What is the relationship between the sets C and D?
2. Let s = {x | x is a parallelogram or trapezoid}, a = {x | x is a parallelogram}, B = {x | x is a diamond}, C = {x | x is a rectangle}, find B ∩ C, cab, CSA

1, denotes point (1,1)
D is really contained in C
2, B ∩ C = {x | x is a square}
What is cab, CSA? Set multiplication?

If X & sup2; + 2mx + n is a complete square, then the relation between M and N is

Then M = n / 2

As shown in the figure, in △ ABC, ab = AC, D, e and F are on three sides respectively, and be = CD, BD = CF, G is the midpoint of EF

Prove: as shown in the figure, connect ed, FD, ∵ AB = AC, ∵ B = ∵ C, be = CD, BD = CF, ≌ bed ≌ CDF, ≌ ed = FD, G is the midpoint of EF, ∵ DG bisects EF vertically

Junior high school mixed operation: 1. (2.5) multiply (- 2 / 5) + (- 5 / 6) divide (- 5 / 2) 2. (1.5) multiply 3 times (- 2 / 3) square 2
Junior high school mixed operation: 1. (2.5) multiply (- two fifths) + (- five sixths) divide (- five fifths)
2. (1.5) times 3 times (- two thirds) square 2 - (one third) times (1.5) 2 square
Answer the process

1. Negative two thirds
2. Five quarters

3000r / (kW · h) is marked on the surface of an electric energy meter used in a family. When it is used to measure the electric power of an electric cooker, in 18 seconds, the small aluminum plate on the electric energy meter rotates 15 turns, what is the electric power of the electric cooker?

Because every 1kW · h of electric energy consumed in the circuit, the small aluminum plate rotates for 3000 revolutions; so when the small aluminum plate rotates for 15 revolutions, the electric energy consumed is: w = 13000r / (kW · h) × 15R = 0.005kw · H = 1.8 × 104j; the rated power of the electric appliance is: P = wt = 1.8 × 104j & nbsp; 18S = 1000W