How many amperes and watts can a 220 V square copper wire carry? What about 380 V? I heard that when the power is more than several kilowatts, the copper wire should be doubled

How many amperes and watts can a 220 V square copper wire carry? What about 380 V? I heard that when the power is more than several kilowatts, the copper wire should be doubled

If it is the national standard, the theoretical value of copper wire per square meter is 1000W, but now there are too many fake wires, single-phase 220V power 1kW current 7a, three-phase 380V Power 1KW current 2A. The current carrying capacity of wires should be checked accurately, and the biggest impact on current carrying capacity is the purity of copper wire, the length of the line, heat dissipation, etc
There is a wire of uniform thickness. The resistance is four ohm. How much resistance is it to fold it in half to make a wire
1 ohm
Half the resistance of the wire is 2 ohm
After folding and paralleling, the cross-sectional area is doubled, and the resistance becomes half of the original, that is, 1 ohm
It's still 4 ohm, but it's more than doubled in cross section
One beat
The resistance of each section of uniform thickness wire is 2 ohm after folding. Two 2-ohm resistors are connected in parallel and the resistance is 1 ohm
How much energy does a kilowatt appliance consume for one hour
Please
At full capacity
Power times time
That is 1000W * 1 hour
That's one kilowatt hour
It is commonly known as one degree power
How many can a 500W 220 V motor start at the same time? How many can a 250W 220 V motor start at the same time?
A 5-amp meter with 500W 220 V motor can start 2 sets at the same time. A 250W 220 V motor can start 4 sets
Cut off half of a uniform metal wire, and then stretch it evenly to the original length. Is the resistance increased compared with the original resistance?
According to the formula r = ρ · L / S
ρ is the density of matter, which is ignored in this problem
Cut off half and then lengthen to the original length,
The deformation of R = L / S is L = R · s
The length L remains the same and the cross-sectional area s becomes smaller
Then, as long as the resistance becomes larger (to conform to the proportional relationship)
yes
Law of resistance: when the material is fixed, the resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area. This is the law of resistance.
Because the cross-sectional area must be smaller than the original length after cutting off half, so the resistance increases
enlarge.
With the same length, the cross-sectional area decreases and the resistance increases
After being cut off, the resistance will become smaller (the same cross-sectional area), because the shorter the conductor is, the smaller the resistance will be. However, if the conductor is evenly elongated to the original length, the cross-sectional area will be one-half of the original, that is, it will be thinner than the original. The thinner the conductor is, the greater the resistance will be. Therefore, the resistance will increase compared with the original resistance
It's increased.
Because the cross-sectional area of the wire is only half of the original.
So the resistance is twice as high
2 times
How many kilowatt hours is equivalent to
One degree electricity
How many watts of load can be used for a long time with a 220 V power supply and a 1 mm diameter copper wire?
The diameter is 1 mm, and the area is 0.785. For continuous operation, we usually take a coefficient of about 6, about 5a, which is equivalent to 1100W. If it is not for continuous operation, the maximum can be taken as 10, about 7.8A, which is equivalent to 1700W
Mainly depends on your load when how much ha!
When a metal wire is evenly stretched, its resistance will change___ (select "large" or "small"); the reason is that the__ No change__ Bigger___ It's getting smaller
When a metal wire is evenly stretched, its resistance will change______ (select "large" or "small"); the reason is that the____ , Getting bigger___ It's getting smaller
When a metal wire is evenly stretched, its resistance will increase because the material of the wire remains unchanged, the length will increase and the cross-sectional area will decrease
Large, resistivity, length, cross-sectional area
According to the law of resistance, r = PL / s, the volume of the metal wire remains unchanged, and the resistance increases with the increase of the length and the decrease of the area
How many kilowatts per hour does 1000 watts consume?
1 degree = 1 kWh
1000 W × 1 h = 1 kwh = 1 degree
1000 watts per hour
The voltage is 220 V and the power consumption is 90 kW
Power consumption 90kw, ask how much the working current, power consumption and power are two different concepts, according to the power consumption to calculate the current is no spectrum thing. Working current and rated current are also two different concepts, rated current can be calculated according to power, and the working current is the actual current of electrical work, it is different from the rated current