Generator current calculator
Full load at fault current ng generator mula sa kVA nito.
Subukan ang isang job 5
Nilalagyan ng halimbawang value ang bawat job. Palitan ang mga ito ng sarili mong value.
- 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.
Mga input
Worked example gamit ang mga default na input.
- Rating
- 100 kVA
- Mga phase
- Three phase
- Voltage
- 400 V
- Power factor
- 0.8
- Subtransient reactance
- 15 %
Full load current
144.34A
- Real power
- 80kW
- Fault current
- 962.25A
Design aid lang ang resultang ito. I-verify ito laban sa kasalukuyang standard.
Mga hakbang ng kalkulasyon
- Full load currentResulta144.34A
- Real power80kW
- Fault current962.25A
Tungkol sa calculator na ito
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.
Mga tanong
Design aid ang resulta. I-verify ito laban sa kasalukuyang standard.
Ano ang ginagawa ng generator calculator?
Iniuulat ng tool ang full load current, ang real power output at ang fault current ng alternator. Gumagana ito mula sa rating sa kilovolt amperes, sa voltage, bilang ng phase, power factor, at subtransient reactance.
Aling mga input ang pinakamahalaga?
Itinatakda ng rating at ng voltage ang full load current. Itinatakda ng power factor ang real power sa kilowatts. Itinatakda ng subtransient reactance ang fault current, na 15 porsyento ang default sa tool. Mas mababang reactance, mas mataas na fault current.
Ano ang mga karaniwang gotcha?
Ang fault current ay ang initial subtransient value, na kinukuha bilang full load current na hinati sa per unit reactance. Gamitin ang value sa machine test sheet kapag mayroon ka nito. Hindi kasama ang cable impedance. Nasa page address ang mga input, kaya muling nagagawa ng link ang resulta.
Mga worked example
- 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.
Background
Mga kaugnay na tool
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