{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"three-phase-power"},"result":{"entity_type":"calculator","id":"three-phase-power","calculator_id":"three-phase-power","canonical_url":"https://tttkmbb.com/engineering/three-phase-power","name":"Three-Phase Power Calculator","title":"Three-Phase Power Calculator – kW, kVA, kVAR and Line Current from Voltage, Current and Power Factor (Wye or Delta)","category":"engineering","category_name":"Engineering & Automotive","tool_name":"calculate_three_phase_power","featured_mcp_tool":false,"description":"Computes real, apparent and reactive power of a balanced three-phase load from line voltage, line current and power factor, or the line current needed for a given real power, and reports the phase voltage and phase current for wye (star) or delta connection.","use_when":"You need the power drawn by a three-phase motor, heater or feeder from its current, the full-load current for a given kW, or the per-phase voltage and current for a wye or delta winding.","do_not_use_when":"The load is unbalanced (compute each phase separately), single-phase (use kva-kw-power-factor or electric-power), or you only know kVA and power factor without a voltage (use kva-kw-power-factor).","inputs":[{"name":"mode","label":"Mode","type":"enum","required":true,"values":[{"value":"power_from_current","label":"Power from voltage and current","aliases":["power","from_current"]},{"value":"current_from_power","label":"Current from real power","aliases":["current","from_power"]}],"description":"power_from_current needs current_a; current_from_power needs real_power_kw.","example":"power_from_current"},{"name":"line_voltage_v","label":"Line-to-line voltage","type":"number","unit":"V","required":false,"default":400,"max":1000000,"exclusive_min":0,"description":"RMS line-to-line voltage (400 V Europe, 480 V North America, 415 V UK/Australia, 208 V US commercial).","example":400},{"name":"current_a","label":"Line current","type":"number","unit":"A","required":false,"min":0,"max":1000000,"description":"RMS line current per conductor (power_from_current mode).","example":10},{"name":"real_power_kw","label":"Real power","type":"number","unit":"kW","required":false,"max":10000000,"exclusive_min":0,"description":"Real (active) power drawn by the load in kilowatts (current_from_power mode); for a motor use input power = shaft kW / efficiency.","example":15},{"name":"power_factor","label":"Power factor","type":"number","required":false,"default":0.85,"max":1,"exclusive_min":0,"description":"cos φ of the load: 0.85 typical for loaded induction motors, 1.0 for resistive heaters.","example":0.85},{"name":"connection","label":"Connection","type":"enum","required":false,"default":"wye","values":[{"value":"wye","label":"Wye / star (Y): V_phase = V_line / √3, I_phase = I_line","aliases":["star","y"]},{"value":"delta","label":"Delta (Δ): V_phase = V_line, I_phase = I_line / √3","aliases":["triangle","d"]}],"description":"Winding connection; it changes only the per-phase values, not the total power.","example":"wye"}],"outputs":[{"name":"real_power_kw","label":"Real power P","type":"number","unit":"kW","decimals":3,"description":"P = √3 × V_L × I_L × PF / 1000."},{"name":"apparent_power_kva","label":"Apparent power S","type":"number","unit":"kVA","decimals":3,"description":"S = √3 × V_L × I_L / 1000."},{"name":"reactive_power_kvar","label":"Reactive power Q","type":"number","unit":"kVAR","decimals":3,"description":"Q = √(S² − P²)."},{"name":"current_a","label":"Line current","type":"number","unit":"A","decimals":3,"description":"I_L = P × 1000 / (√3 × V_L × PF), or the given current."},{"name":"phase_voltage_v","label":"Phase voltage","type":"number","unit":"V","decimals":2,"description":"Voltage across one winding: V_L / √3 for wye, V_L for delta."},{"name":"phase_current_a","label":"Phase current","type":"number","unit":"A","decimals":3,"description":"Current through one winding: I_L for wye, I_L / √3 for delta."},{"name":"power_per_phase_kw","label":"Power per phase","type":"number","unit":"kW","decimals":3,"description":"P / 3 = V_phase × I_phase × PF / 1000."},{"name":"phase_angle_degrees","label":"Phase angle φ","type":"number","unit":"°","decimals":2,"description":"arccos(power_factor)."}],"input_schema":{"type":"object","properties":{"mode":{"description":"power_from_current needs current_a; current_from_power needs real_power_kw.","type":"string","enum":["power_from_current","current_from_power"],"examples":["power_from_current"]},"line_voltage_v":{"description":"RMS line-to-line voltage (400 V Europe, 480 V North America, 415 V UK/Australia, 208 V US commercial). Unit: V.","type":"number","maximum":1000000,"exclusiveMinimum":0,"default":400,"examples":[400],"x-unit":"V"},"current_a":{"description":"RMS line current per conductor (power_from_current mode). Unit: A.","type":"number","minimum":0,"maximum":1000000,"examples":[10],"x-unit":"A"},"real_power_kw":{"description":"Real (active) power drawn by the load in kilowatts (current_from_power mode); for a motor use input power = shaft kW / efficiency. Unit: kW.","type":"number","maximum":10000000,"exclusiveMinimum":0,"examples":[15],"x-unit":"kW"},"power_factor":{"description":"cos φ of the load: 0.85 typical for loaded induction motors, 1.0 for resistive heaters.","type":"number","maximum":1,"exclusiveMinimum":0,"default":0.85,"examples":[0.85]},"connection":{"description":"Winding connection; it changes only the per-phase values, not the total power.","type":"string","enum":["wye","delta"],"default":"wye","examples":["wye"]}},"additionalProperties":false,"required":["mode"]},"output_schema":{"type":"object","properties":{"real_power_kw":{"description":"P = √3 × V_L × I_L × PF / 1000. Unit: kW.","type":"number","x-unit":"kW"},"apparent_power_kva":{"description":"S = √3 × V_L × I_L / 1000. Unit: kVA.","type":"number","x-unit":"kVA"},"reactive_power_kvar":{"description":"Q = √(S² − P²). Unit: kVAR.","type":"number","x-unit":"kVAR"},"current_a":{"description":"I_L = P × 1000 / (√3 × V_L × PF), or the given current. Unit: A.","type":"number","x-unit":"A"},"phase_voltage_v":{"description":"Voltage across one winding: V_L / √3 for wye, V_L for delta. Unit: V.","type":"number","x-unit":"V"},"phase_current_a":{"description":"Current through one winding: I_L for wye, I_L / √3 for delta. Unit: A.","type":"number","x-unit":"A"},"power_per_phase_kw":{"description":"P / 3 = V_phase × I_phase × PF / 1000. Unit: kW.","type":"number","x-unit":"kW"},"phase_angle_degrees":{"description":"arccos(power_factor). Unit: °.","type":"number","x-unit":"°"}}},"formula":"apparent_power_kva = √3 × line_voltage_v × current_a / 1000; real_power_kw = apparent_power_kva × power_factor; reactive_power_kvar = √(S² − P²); current_a = real_power_kw × 1000 / (√3 × line_voltage_v × power_factor); wye: phase_voltage_v = line_voltage_v / √3, phase_current_a = current_a; delta: phase_voltage_v = line_voltage_v, phase_current_a = current_a / √3; power_per_phase_kw = real_power_kw / 3","method":"Balanced sinusoidal three-phase system: the √3 relations hold for both wye and delta when line quantities are used, so total power does not depend on the connection. Motor nameplate kW is shaft output; divide by efficiency to obtain the electrical input power before computing current.","sources":[{"name":"Wikipedia – Three-phase electric power","url":"https://en.wikipedia.org/wiki/Three-phase_electric_power","type":"reference","retrieved_at":"2026-09-24"},{"name":"Wikipedia – AC power","url":"https://en.wikipedia.org/wiki/AC_power","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"400 V, 10 A, PF 0.85, wye","inputs":{"mode":"power_from_current","line_voltage_v":400,"current_a":10,"power_factor":0.85,"connection":"wye"},"expected":{"real_power_kw":5.889,"apparent_power_kva":6.928,"reactive_power_kvar":3.65,"current_a":10,"phase_voltage_v":230.94,"phase_current_a":10,"power_per_phase_kw":1.963},"url":"https://tttkmbb.com/api/v1/calculate/three-phase-power?mode=power_from_current&line_voltage_v=400&current_a=10&power_factor=0.85&connection=wye"},{"name":"15 kW at 400 V, PF 0.85, delta","inputs":{"mode":"current_from_power","line_voltage_v":400,"real_power_kw":15,"power_factor":0.85,"connection":"delta"},"expected":{"current_a":25.471,"apparent_power_kva":17.647,"reactive_power_kvar":9.296,"phase_voltage_v":400,"phase_current_a":14.706},"url":"https://tttkmbb.com/api/v1/calculate/three-phase-power?mode=current_from_power&line_voltage_v=400&real_power_kw=15&power_factor=0.85&connection=delta"}],"faq":[{"q":"Why does the connection not change the power?","a":"With line-to-line voltage and line current the power is √3 × V_L × I_L × PF in both cases; wye and delta only differ in how that splits into winding voltage and winding current."},{"q":"Is the voltage line-to-line or line-to-neutral?","a":"Enter the line-to-line (phase-to-phase) voltage, e.g. 400 V in a 230/400 V system; the calculator reports the 230 V line-to-neutral value as the wye phase voltage."},{"q":"How do I get a motor's current from its nameplate kW?","a":"Nameplate kW is mechanical output; use real_power_kw = kW / efficiency (e.g. 15 / 0.9 = 16.7 kW) with the nameplate power factor for a realistic full-load current."}],"tags":["three phase power","3 phase current calculator","kw to amps 3 phase","wye delta","line current","three phase kva"],"related":[{"calculator_id":"kva-kw-power-factor","reason":"Complete the power triangle from any two power quantities."},{"calculator_id":"wire-voltage-drop","reason":"Voltage drop of the three-phase feeder at this current."},{"calculator_id":"electric-power","reason":"Single-phase and DC power P = V × I."}],"links":{"html":"https://tttkmbb.com/engineering/three-phase-power","markdown":"https://tttkmbb.com/engineering/three-phase-power.md","json":"https://tttkmbb.com/engineering/three-phase-power.json","api":"https://tttkmbb.com/api/v1/calculate/three-phase-power","schema":"https://tttkmbb.com/api/v1/calculators/three-phase-power","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T03:45:42Z","next_actions":[{"tool":"run_calculator","calculator_id":"three-phase-power","reason":"Run Three-Phase Power Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/engineering/three-phase-power.md"}}