Tātaitai iahiko generator
Te iahiko uta katoa me te iahiko hapa o tētahi generator mai i tōna kVA.
Whakamātau mahi 5
Ka whakakī ia mahi i ngā uara tauira. Whakakapia ērā ki ō uara.
- Check a 60 kVA standby generatorThe full load current and the fault current of a 60 kVA set at 400 V.
- Check a 200 kVA generatorThe full load current of a 200 kVA set at 400 V.
- Check a portable generatorThe current of a 10 kVA single‑phase set.
- Find a generator's fault currentThe fault current of a 500 kVA set at 15 % reactance.
- Check a holiday park backup setThe current and fault level of a 150 kVA set.
Ngā whakauru
He tauira mahi me ngā whakauru taunoa.
- Reiti
- 100 kVA
- Ngā wāhanga
- Wāhanga toru
- Voltage
- 400 V
- Power factor
- 0.8
- Subtransient reactance
- 15 %
Iahiko Uta Katoa
144.34A
- Real power
- 80kW
- Au hapa
- 962.25A
He āwhina hoahoa tēnei hua. Manatokohia ki te paerewa o nāianei.
Ngā hīkoi tātaitanga
- Au utanga katoaHua144.34A
- Pūngao tūturu80kW
- Au hapa962.25A
Mō tēnei tātaitai
How this is calculated
The tool works from the kVA rating on the generator nameplate. It gives the full load current, the real power and the fault current at the terminals. The steps are plain circuit arithmetic. The tool reads no Standard table.
- Apparent power. You enter the rating in kVA. The tool converts it to VA.
- Full load current. On three phases the tool divides the VA by √3 times the line voltage. On one phase it divides by the voltage.
- Real power. It multiplies the kVA by the power factor you enter. The result is in kW.
- Fault current. It divides the full load current by the subtransient reactance, as a fraction. This is the first-cycle symmetrical value.
| Step | Basis | What it decides |
|---|---|---|
| Full load current | I = S / (√3 × V) | The current at rated output |
| Real power | P = S × power factor | The load the engine must drive |
| Fault current | I / X″d | The first-cycle fault level at the terminals |
Worked example
A 200 kVA set at 400 V on three phases has a power factor of 0.8. Its subtransient reactance is 15 %. The full load current is 288.68 A. The real power is 160 kW. The fault current is 1,924.5 A.
Limits
- The fault current is the initial symmetrical value only. It ignores the decay to the transient and synchronous values.
- It ignores any excitation limit. A few cycles in, the real current is much lower.
- The tool does not size the generator for motor starting or step loads.
- It does not size the cable or the protective device. Use the cable size calculator for the cable.
- The subtransient reactance comes from the maker data sheet. No default fits every set.
See also: Generator fault current from the subtransient reactance, Generator full load current from kVA and the fault level calculator.
Pātai
He āwhina hoahoa te hua. Manatokohia ki te paerewa o nāianei.
He aha te mahi a te tātaitai generator?
Ka whakaatu te taputapu i te Iahiko Uta Katoa, te mana whakaputa pūngao pono me te iahiko hapa o tētahi alternator. Ka mahi mai i te rating i ngā kilovolt amperes, te voltage, te maha o ngā wāhanga, te power factor me te subtransient reactance.
Ko ēhea ngā uruhanga e tino nui ana?
Ko te reiti me te voltage e whakatau ana i te iahiko uta katoa. Ko te power factor e whakatau ana i te real power i ngā kilowatt. Ko te subtransient reactance e whakatau ana i te iahiko hapa, ko te taunoa he 15 ōrau i te taputapu. He iti iho te reactance, he nui ake te iahiko hapa.
He aha ngā raru noa?
Ko te iahiko hapa te uara subtransient tuatahi, ka tangohia hei iahiko uta katoa ka wehea ki te per unit reactance. Whakamahia te uara pepa whakamātautau miihini ina whai koe tētahi. Kāore i uru te impedance taura. Ka noho ngā uruhanga ki te wāhitau o te whārangi, nō reira ka whakaputa tētahi hononga i te putanga.
Ngā tauira mahi
- Generator fault current calculation at 400 VA 500 kVA 400 V standby set at 12 % subtransient reactance gives 721.69 A full load and 6014.07 A fault current, with the decay the figure leaves out.
- What size generator for a dairy shedSize a standby set for a dairy shed from its load list. The vacuum pump's start sets the size, then staggered steps, a drive and a soft starter shrink it.
- Generator full load current: 200 kVA to ampsA 200 kVA 400 V standby set converted to 288.68 A of full load current, 160 kW of real power and 2,405.63 A of initial fault current from 12 % reactance.
- Generator sizing for a 150 kVA holiday parkA 150 kVA three‑phase standby set at 400 V gives 216.51 A full load current, 120 kW real power and 1443.38 A fault current from one nameplate.
Kōrero o muri
Ngā taputapu hononga
- Rahi generator mai i tētahi Rārangi UtaSize a generator from a load list with motor starting.Kāore he paerewa
- Tātaitai mōtāFind motor full load current, starting current and torque.Kāore he paerewa
- Tātaitai Maximum DemandEstimate maximum demand for domestic or non‑domestic loads.AS/NZS 3000 Table C1/C2
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