The power consumption of a three-phase ac motor is equal to the line voltage cross current. How do you explain?
For three-phase motor delta connection or y connection is 3 P =) * 380 v * I * COS Φ, line voltage is 380 v, the other is wrong, don't know your the formula given to come from. If you don't multiply the square root of 3, the load will be single phase.
The formula for calculating the dynamical power of an electric machine: P = UI * square root of 3 * com. U: line voltage, which is what we call 308V, I: the phase current, and the phase current times the square root of 3, not the line current? Line voltage * current = electric motor is seen in power. If the actual power of the motor is calculated (in other words, how much electricity is used), it will also have to be the power factor and utilization.
This is the basic formula! Validation; Line voltage is equal to phase voltage square root of 3, phase voltage is equal to line voltage over square root of 3, and line current is equal to phase current. Cases; Three-phase symmetric load, line voltage = 380v phase voltage = 219.4 v (phase 3) current each has 10A power factor = 0.8 Compute power; 1. P = square root of 3 U line I line cosine phi = 1.732 * 380 * 10 * 0.8 = 5265.28 w P = 3U phase I cosine phi = 3 * 219.4 * 10 * 0.8 = 5265.6 w (3 phase power) Type; Phase voltage = line voltage/square root of 3 = 380/1.732 = 219.3995 v The calculation is pretty much the same, so the wire current is equal to the current.
Line voltage, the line current indicates the input of the motor, and of course it is related to the actual power consumption of the three-phase motor. But you should also multiply by the square root of 3, and multiply by the power factor, which is the actual power consumption. I estimate that the questioner does not understand the difference between line voltage, line current and phase voltage and phase current. Line voltage and line current is standing on the power supply, or standing on the outside to consider the problem of electrical equipment, and the phase voltage, phase current is standing on the internal electrical equipment to consider a problem. A physical quantity such as power is a global quantity, and the use of line voltage and line current is of course more convenient and direct.
The calculation formula of three-phase symmetric load; The power P is equal to the square root of 3 U line I cosine phi is 3I2R. The line voltage refers to the parallel voltage between the two phase lines (a-b a-c b-c), and the phase voltage refers to the parallel voltage of the relative zero (a-0, b-0, c-0). In a power distribution system that is directly grounded in three phase four lines; Line voltage is equal to phase voltage square root of 3, phase voltage is equal to line voltage over square root of 3, line current equals phase current.
