To step up voltage from 220 to 380V for a 45kW 3-phase air compressor, you would need a transformer with a capacity of at least 64kVA. This calculation is based on the formula: kVA = (kW * 1000) / (Voltage * √3). It's important to consider other factors such as efficiency, voltage regulation, and potential future load increases when selecting the transformer.
W (Watts) refers to the resistive (real) power of an appliance. Providing that the circuit is purely resistive then 60kW = 60kVA, if the appliance circuit includes capacitance / inductance more information is needed to answer the question such as the power factor or phase bewtween voltage and current. Assuming a house supply of 240 V (rms), 60kVA would represent a current of 60k/240 = 250 Amps. Note that a single house ring mains fuse/trip is usually 60 Amps.
160 Amp. MCCB 45 KW Contactor (67.5-112.5) Thermal Over Load
At 2965 rpm it sounds like an induction motor for a 50 Hz supply. A 45 kW motor would draw about 55 kW from the supply with a power factor of 0.85, so that is 65 kVA, and on a 415 v 3-phase supply that is a current of 90 amps. For armoured XLPE cale the size needed is at least 16 mm2 Probably 25 mm2 would be preferred for a permanent installation but it would depend on how the cable is installed, how much free air movement there is around it etc.
watt (w) means joules per second. kW (kilowatts) means thousands of joules per second. Multiply that by 3600 to get the joules used per hour.
To answer this question, wire size is rated in the amount of amperage that it can legally carry. The formula to find amperage when the HP is known is I = HP x 746/1.73 x E x %eff x pf. A standard motor's efficiency between 5 to 100 HP is .84 to .91. A standard motor's power factor between 10 to 100 HP is .86 to .92. Amps = 60 x 746 = 45000 = 45000/ 1.73 x 415 x .87 x .87 = 45000/718 = 62.7 amps. The electrical code states that a motor conductor has to be rated at 125% of the motors full load amperage. 62.7 x 125% = 78 amps A #4 copper conductor with an insulation factor of 75 or 90 degrees C is rated at 85 and 95 amps respectively. A #3 copper conductor will limit the voltage drop to 2% or less when supplying 78 amps for 50 metres on a 415 volt system.