I would like to know the formula for squaring 380V with current

Current of the load (in cos):

i p large cross-section copper core wire per square safety current carrying about, wire cross-section:

s 227 3 95 square If the power supply distance is long, use 120 square meters.

Estimation of the safe ampacity of various insulated conductors.

Formula 1: 2.5 down the whole nine times, up minus one straight number pair, three or five lines multiply 3.5, double and double groups halved times.

Note: "2.5 times the whole nine, up minus one straight pair," that is; That is, the following various aluminum core insulated wires have a safe current carrying capacity of from, from 4mm; Above, the relationship between the safe ampacity of the wire and the cross-section is: the wire number is arranged upward, and the multiple is gradually reduced by one; and 35mm; The safe ampacity of the wire is a multiple of the cross-section; That is, "three or five lines multiply three point five", 50mm; Above, the multiplier relationship between the number of cross-sections and the safety current is a group of two wire numbers, and the multiples are reduced in turn.

That is, "double and double in groups halved".

Special note: The table is suitable for aluminum wire insulated wires, and the ambient temperature is 25; c. Applying it openly. When the ambient temperature rises, the laying method changes, and when copper wire is used, it can be corrected by the following estimation method.

Formula 2: "Different conditions are treated separately, and high-temperature nine-fold copper is upgraded." Wire threading.

Two, three, four, eight, seven, six folds are the best to remember. ”

Note: When the wire used is a copper wire, its safe current carrying capacity is slightly larger than that of the aluminum wire of the same specification, which can be calculated by adding a wire number according to the table. If calculated as 16mm; of copper wire, which can be regarded as 25mm; The aluminum wire, with the formula one has 25 4 = 100a, that is, "high temperature nine-fold copper upgrade".

The number of wires threading through the pipe increases, and the safe current carrying capacity of the wires decreases. The estimate can be regarded as an open application, with a discount. The safe current when one tube passes through two wires is twice that of the open application.

380V Current Calculation Method:

The current calculation formula of 380V motor (three-phase air conditioning compressor) is: i rated power, rated voltage, power factor, efficiency). For example, if the power factor of a 10 kW motor is, then i = 10000 x 380 x = 16a.

Power factor is an important technical data of the power system. The power factor is a factor that measures the efficiency of electrical equipment. The low power factor indicates that the reactive power of the circuit for alternating magnetic field conversion is large, which reduces the utilization rate of the equipment and increases the power supply loss of the line.

Three-phase power connection.

Commonly used are star connections (i.e., y-shaped) and triangular connections (i.e., shapes). The three wires that lead out from the three ends of the power supply are called end wires (commonly known as live wires). The voltage between any two end wires is known as the line voltage.

When the star is connected, the line voltage is a multiple of the phase voltage; The phase difference between the three line voltages is still 120°, which is 30° ahead of each of the three phase voltages. The star connection has a common point, called the neutral point.

When the triangle is connected, the line voltage is equal to the phase voltage, and the three power supplies form a loop, and only when the three-phase power supply is symmetrical and connected correctly, there is no circulation inside the power supply.

The current calculation of the three-phase motor i= p ( where: p is the three-phase power (is the root number 3) 380 is the three-phase line voltage (i is the three-phase line current) is the power factor, here the power factor is taken , if the power factor is taken or, the calculated current is still small. Motors that are not particularly advanced are calculated by calculation.

Calculated according to 10kw: i = 10kw ( = a three-phase motor must be three-phase power supply, when the 10kw motor is working, the working current of the three power lines is a When calculating the actual circuit, it is necessary to consider the use coefficient, starting current and other factors to determine the cross-sectional area of the wire, the empty opening and the setting current of the empty opening.

380V Current Calculation Method:The current calculation formula of 380V motor (three-phase air conditioning compressor) is: i rated power rated voltage power factor efficiency ), if the power factor of 10 kW motor is, then i = 10000 x 380 x = 16a.

The power factor is an important technical data of the power system, the power factor is a coefficient to measure the efficiency of electrical equipment, and the low power factor indicates that the reactive power of the circuit for alternating magnetic field conversion is large, thereby reducing the utilization rate of the equipment and increasing the loss of line power supply.

Cable current carrying port:Multiply by nine at 2.5 and subtract one by one straight up.

Thirty-five times 3.5, double in a group minus five.

The conditions have been changed and converted, and the high-temperature nine-fold copper has been upgraded.

The number of pipe roots is two, three, four, eight, seven and six folds full of load current.

This formula is set under the condition that the corresponding aluminum wire is set under the condition of 25 ° of open application, and does not take into account factors such as the length of the wire, multiply 5 by 10 square meters or less, and multiply 2 by 2 more than 100 square meters, but 25 square meters and 35 square meters are four times and three times the dividing line, for example, the wire is 16 square meters, just between 10 square meters and 25 square meters, so it should be multiplied by 4, if the cross-sectional area of the wire is between 35 square meters and 100 square meters, multiply by these two specifications directly.