Calculation of three-phase electrical equipment
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I have a question that puzzles me: given the power and voltage of a three-phase electrical device, how can one estimate its rated current?
It depends on your connection method; different connection methods, such as star connection and delta connection, require different calculation approaches.
1# SHY0528 I=P/√3Ucos￠ I: Line current. P: Three-phase power. U: Line voltage. cos￠: Power factor. △ Connection: U wire = U phase, I wire = √3I phase. Wye connection: U_line = √3U_phase, I_phase = I_line.
Regarding the data on the nameplate, both the voltage and current refer to line voltage and line current; therefore, there is no causal relationship with the specific wiring method! In other words, when designing a motor, the first thing that is determined is the power ； Line voltage, line current ； Then determine its wiring method!
It’s clearly stated on the 4th floor: use the data on the nameplate and then apply the calculation method from the 3rd floor
The rated current is the rated apparent current of the device, given by I=P/√3Ucosφ. To calculate it, one needs to know the power, voltage, as well as the power factor.
I don’t know what you mean by that question. Here’s some reference for you. . Three-phase 380V loads (such as motors) can be simply remembered as: current = 2 times power