Tātaitai Iahiko Uta Katoa
Tātaitia te iahiko uta katoa mai i te mana, te voltage me te wāhanga.
Whakamātau mahi 6
Ka whakakī ia mahi i ngā uara tauira. Whakakapia ērā ki ō uara.
- Find a 22 kW motor's full load currentThe line current a 22 kW three phase motor takes at 400 V.
- Find the current of a 7.2 kW chargerThe current of a single‑phase 7.2 kW load.
- Find the current of 100 kVAThe line current of a 100 kVA load at 400 V.
- Find the current of a 3 kW heaterThe current of a 3 kW heater at 230 V.
- Find the current of a chillerThe current of a 45 kW chiller at 0.85 power factor.
- Find the current of a commercial ovenThe current of a 15 kW three‑phase oven.
Ngā whakauru
He tauira mahi me ngā whakauru taunoa.
- Ngā wāhanga
- Wāhanga toru
- Voltage
- 400 V
- Wae whakatauhanga
- kW
- Reiti
- 15
- Power factor
- 0.9
- Pai
- 1
Iahiko Uta Katoa
24.06A
- Pūngao ariā kukumea
- 16.67kVA
- Pūngao putanga
- 15kW
He āwhina hoahoa tēnei hua. Manatokohia ki te paerewa o nāianei.
Ngā hīkoi tātaitanga
- Hiko puta15kW
- Pūngao ariā kukumea16.67kVA
- Au utanga katoaHua24.06A
Mō tēnei tātaitai
How this is calculated
The tool works out the full load current of a load. It uses the power, the voltage, the power factor and the efficiency. It works on one phase or three. It reads no table, so it cites no clause.
- Supply. You pick one phase or three and enter the voltage. The voltage you enter sets the divisor in the last step.
- Output power. You enter the load in kW or kVA. For a kW load, the tool takes this as the output power.
- Apparent power drawn. It divides the output power by the efficiency and by the power factor. A kVA entry skips the power factor step.
- Full load current. On one phase, it divides the apparent power by the voltage. On three phases, it divides by the voltage and by the square root of three.
On three phases, enter the line voltage, such as 400 V. On one phase, enter the phase voltage, such as 230 V.
Worked example
- A 15 kW three‑phase load at 400 V. The power factor is 0.9 and the efficiency is 1. The apparent power drawn is 16.67 kVA. The full load current is 24.06 A.
Limits
The result is the steady running current. It is not the starting current. A motor draws more current at start. Use the motor tool for the starting current.
The tool assumes a balanced load on three phases. It does not add a margin for the cable or the breaker. Size the cable from the design current with the cable size calculator. The tool gives no harmonic or neutral current.
Efficiency is a value between 0 and 1. A kVA entry is already an apparent power, so the tool does not divide it by the power factor.
Check the efficiency you enter. A motor rating in kW is a shaft output, so enter the motor efficiency. A resistive heater has an efficiency of 1. Check the power factor on the nameplate. A low power factor raises the current for the same kW.
See also: Commercial kitchen kW to amps, Three‑phase power kVA to amps at 400 V and the three‑phase power tool.
Pātai
He āwhina hoahoa te hua. Manatokohia ki te paerewa o nāianei.
He aha te mahi a te tātaitai iahiko uta katoa?
Ka hurihia e te taputapu te reiti uta ki tētahi iahiko. Uruhia te reiti ki ngā kilowatt, ki ngā kilovolt amperes rānei, te voltage me te tatau wāhanga. Ka pūrongo i te iahiko uta katoa o te uta, tōna real power me tōna apparent power.
Ko ēhea ngā uruhanga e tino nui ana?
Ko te reiti me te voltage e whakatau ana i te iahiko. Mō tētahi reiti kilowatt, ko te power factor me te efficiency e whakatairanga ana i te apparent power, nō reira e whakatairanga ana i te iahiko. Mō tētahi reiti kilovolt ampere kāore te efficiency e whakamahia. Ko te putanga wāhanga toru ka whakawehea ki te pūtakere o te toru.
He aha ngā mea kāore e mahia e tēnei taputapu?
Kāore e rahi i tētahi taura, i tētahi taputapu whakamaru. Kāore he tūtohi paerewa e tohua ana, nō te mea he tātaitanga tōtika te putanga. Whakamahia te iahiko e hoatu ana e ia hei iahiko hoahoa i te taputapu Rahi Taura. Ka noho ngā uruhanga ki te wāhitau o te whārangi, nō reira ka whakaputa tētahi hononga i te putanga.
Ngā tauira mahi
- Commercial kitchen kW to amps full load currentTurning a 30 kW commercial kitchen nameplate load into 45.58 A at 400 V three phase, with the power factor step that a plain kW to amps sum leaves out.
- 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.
- Motor circuit for a 15 kW pump: DOL or star-deltaSize a 15 kW 400 V pump circuit: cable, breaker, contactor and overload relay. Compare DOL, star-delta, soft starter and drive starts.
- 22 kW EV charger amps at 400 V three‑phaseA 22 kW three‑phase EV charger draws 31.75 A at 400 V. See the inputs, the clause, the arithmetic and the current that feeds cable sizing and demand.
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.
- Control panels and PLC wiringSegregation of LV and ELV in a control panel, terminal and numbering practice, panel earthing, and the 24 V DC voltage drop that long instrument loops fail on.
- Motor circuits and startingHow full load current sizes the cable and starting current sizes the device on a motor circuit, with a worked 22 kW 400 V motor and the cable the tool selects.
- 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.
- Industrial switchboards: fault rating, form, IPWhat the three ratings on an industrial switchboard or motor control centre mean, how each one is chosen, and which AmpSize tools feed the numbers behind them.
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