Tātaitai Power Wāhanga Toru
Hurihia i waenga i te power, te iahiko, te voltage me te power factor.
Whakamātau mahi 5
Ka whakakī ia mahi i ngā uara tauira. Whakakapia ērā ki ō uara.
- Convert amps to three phase powerThe kW and kVA of a 63 A three phase load at 400 V.
- Find kW from a clamp readingThe kW of 100 A at 0.8 power factor.
- Find the kVA of a single‑phase loadThe kVA of 40 A at 230 V.
- Find the reactive power of a loadThe kvar of 50 A at 0.7 power factor.
- Turn a meter reading into kWThe kW from a metered current and power factor.
Ngā whakauru
He tauira mahi me ngā whakauru taunoa.
- Ngā wāhanga
- Wāhanga toru
- Voltage
- 400 V
- Iahiko
- 50 A
- Power factor
- 0.9
Apparent power
34.64kVA
- Real power
- 31.18kW
- Reactive power
- 15.1kvar
He āwhina hoahoa tēnei hua. Manatokohia ki te paerewa o nāianei.
Ngā hīkoi tātaitanga
- Pūngao ariāHua34.64kVA
- Pūngao tūturu31.18kW
- Pūngao rerekē15.1kvar
Mō tēnei tātaitai
How this is calculated
The tool converts between current, apparent power, real power and reactive power. It works on one phase or on three. It does not read a standard. The method is the power triangle.
- Inputs. You pick one phase or three. You enter the voltage, the current and the power factor. On three phases the voltage is the line voltage.
- Apparent power. On three phases, S = √3 × V × I ÷ 1000. On one phase, S = V × I ÷ 1000. The result is in kVA.
- Real power. P = S × power factor. The result is in kW.
- Reactive power. Q = √(S² − P²). The result is in kvar.
Enter the line voltage on three phases, such as 400 V. Enter the phase voltage on one phase, such as 230 V.
Worked example
- 50 A at 400 V on three phases, power factor 0.9. The apparent power is 34.64 kVA. The real power is 31.18 kW. The reactive power is 15.1 kvar.
Limits
The tool assumes a balanced load. It assumes a sine wave. A load with harmonics needs a true RMS reading. The tool does not size a cable or a device. Use the cable size calculator for that. A motor has efficiency as well as power factor. Use the motor tool for its full load current.
Use the tool to check a meter reading, a motor plate or a supply request. For a load in kW, the full load current tool works the other way. A low power factor raises the kVA for the same kW. The power factor correction tool finds the capacitor size.
See also: kVA to amps at 400 V, Current and power factor to kW and Power factor and reactive power.
Pātai
He āwhina hoahoa te hua. Manatokohia ki te paerewa o nāianei.
He aha te mahi a te tātaitai Power Wāhanga Toru?
Ka hurihia e te taputapu tētahi voltage, tētahi iahiko me tētahi power factor ki te apparent power, real power me te reactive power. Ka mahi i tētahi wāhanga kotahi, i ngā wāhanga toru rānei. Ko te putanga wāhanga toru ka whakamahi i te pūtakere o te toru me te line voltage.
Ko ēhea ngā uruhanga e tino nui ana?
Ko te voltage me te iahiko e whakatau ana i te apparent power. Ko te power factor e wehe ana taua apparent power ki te real power me te reactive power. Ko te power factor 1 kāore e hoatu he reactive power. Ina toru ngā wāhanga, uruhia te voltage line to line, ehara i te voltage wāhanga-ki-te-neutral.
He aha ngā raru noa?
Ka tātaitia e te taputapu te reactive power mai i ngā rahinga. Nō reira kāore e whakaatu mēnā te uta e leading, e lagging rānei. Ka whakaaro te putanga ki ngā wāhanga e toru e kawe ana i ngā uta ōrite, taurite. Ka noho ngā uruhanga ki te wāhitau o te whārangi, nō reira ka whakaatu tētahi hononga i taua hurihanga ōrite.
Ngā tauira mahi
- Ohm's law on a 3 kW water heater elementWork the current and working resistance of a 3 kW, 230 V water heater element with Ohm's law, why a cold meter reading is lower, then a 9 kW three‑phase bank.
- Three‑phase power: kVA to amps at 400 VThe root three relation between amps, kVA and kW on a 400 V board, worked at 50 A and a 0.9 power factor, with the kvar figure the engine returns.
Kōrero o muri
- Ohm's law and power on d.c. and a.c.Ohm's law and the power formulas on d.c., single‑phase and three‑phase a.c.: how power factor and impedance change them, and how any two values give the rest.
- Maximum demand and diversityWhy consumer mains are smaller than the sum of the loads. The four methods of Cl 2.2.2, the Table C1 groups, and a house that lands on 70.18 A.
- Power factor and reactive powerWhat power factor is, why a low one costs current and capacity, how a capacitor bank corrects it in steps, and when harmonics call for a detuned bank.
- Harmonics and neutral sizingWhy third harmonic current adds in the neutral of a four‑wire circuit, what the 0.86 factor does, and how to apply it by hand to a cable size result.
Ngā taputapu hononga
- Iahiko neutral o tētahi uta kore tauriteThe neutral current of an unbalanced three‑phase load.AS/NZS 3000
- Tātaitai Iahiko Uta KatoaCalculate full load current from power, voltage and phase.Kāore he paerewa
- Tātaitai rahi tauraFind the smallest cable size that passes each check.AS/NZS 3008.1.2AS/NZS 3008.1.1AS/NZS 3000
He whai hua tēnei?
He pātai, he uara rānei e kitea ana he hē? Whakapā mai.