U1-u2 / i1-i2 in the UI diagram for measuring the electromotive force of the power supply indicates that the calculated resistance is the power supply resistance? Why?

U1-u2 / i1-i2 in the UI diagram for measuring the electromotive force of the power supply indicates that the calculated resistance is the power supply resistance? Why?

Hope to adopt!

When the voltage at both ends of a resistor increases from U1 to U2, its current increases from I1 to I2. Try to prove that r = u2-u1 / i2-i1

The voltage at both ends is U1 and the current is I1, so the resistance R = U1 / I1
The voltage at both ends is U2 and the current is I2, so the resistance R = U2 / I2
So there is: U2 / I2 = U1 / I1
According to the formula of combining and dividing ratio:
If a: B = C: D and B-D ≠ 0, then (A-C): (B-D) = A: B = C: D;
So u2-u1 / i2-i1 = U2 / I2 = U1 / I1 = R

How many kilowatts can three-phase 380 volt aluminum wire with 35 square meters carry?
The 35 square aluminum wire is 40 meters long and 30 meters underground. It is three-phase and three wire. How much kilowatts can it have at most? In addition, how to calculate the diameter of three-phase and three wire and its current and power?

23KW

46 + 21 + 3 a total of 70 kW motor (3-phase 380 V) how many square aluminum wire?

70kw load selection cable
Rated current I = P / 1.732ucos Φ = 70 / 1.732/0.38/0.8 = 70 / 0.53 = 132a
If it is close (within tens of meters), copper cable 35 square mm, aluminum cable 50 square mm
If it is a long distance (several hundred meters), copper cable 70 square mm, aluminum cable 120 square mm
If it is between short distance and long distance, copper cable is 50 square millimeter, aluminum cable is 90 square millimeter

Copper wire 1 square wire is equal to how many ampere, 1a is equal to how many watt

It is very difficult to get an accurate over-current data of copper core wire, because there are different situations according to the different materials, laying methods and use methods of wires. Generally speaking, it can only ensure the use of wires in a relatively safe range: 1.5 square meters below 10a, 2.5 square meters below 15a, 4 square meters below 20a and 6 square meters below 30A

Under normal circumstances, how many watts of electrical appliances can 1.5 square meters of national standard copper wire drive?

The safe current carrying capacity of 1.5 square meter national standard copper wire is 11a. If the single-phase power supply is 220 V, it can carry about 2 200 W. if the three-phase power supply is 380 V, it can carry about 4 000 W

How many watts can a 2.5 square line carry

4400w

10A circuit breaker can carry many w electrical appliances

Single phase load: according to the formula P = UI, P = 220x10 = 2200W;
Three phase load: from the formula P = √ 3uicos φ, P = 1.73x380x10x0.83 = 5456w

I would like to ask the next household appliances, 8kw water overheating need how much square copper wire, and how much leakage protection switch

6 square conductor and 40A leakage switch

Knowledge of leakage protection switch

Leakage protection switch is used to protect the safety of life. When people get an electric shock, part of the current is led to the earth through the human body. At this time, the vector sum of the current of the leakage protection switch is not zero. Therefore, the tripping device in the leakage protection switch is started to disconnect the current and protect the safety of life