Transformer calculator
Kalkulahin ang transformer full load current at impedance.
Subukan ang isang job 5
Nilalagyan ng halimbawang value ang bawat job. Palitan ang mga ito ng sarili mong value.
- Check a transformer secondaryThe secondary current and the fault level of a 1000 kVA unit.
- Find the currents of a 500 kVA transformerThe primary and secondary currents of a 500 kVA unit.
- Find fault level of a 300 kVA unitThe secondary fault current at 4 % impedance.
- Check an isolating transformerThe currents of a 5 kVA single‑phase unit.
- Check a 22 kV transformerThe primary current of a 1500 kVA, 22 kV unit.
Mga input
Worked example gamit ang mga default na input.
- Rating
- 500 kVA
- Mga phase
- Three phase
- Primary voltage
- 11,000 V
- Secondary voltage
- 400 V
- Impedance
- 6 %
Secondary full load current
721.69A
- Primary full load current
- 26.24A
- Secondary fault current
- 12,028.13A
Design aid lang ang resultang ito. I-verify ito laban sa kasalukuyang standard.
Mga hakbang ng kalkulasyon
- Primary full load current26.24A
- Secondary full load currentResulta721.69A
- Secondary fault current12,028.13A
Tungkol sa calculator na ito
How this is calculated
The tool gives the full load currents of a transformer and its secondary fault current. It uses the rating and the impedance from the nameplate.
- Inputs. You enter the rating in kVA and the number of phases. You also enter both voltages and the impedance in percent.
- Primary full load current. On three phases, I = kVA × 1000 ÷ (√3 × primary voltage). On one phase, it divides by the voltage alone.
- Secondary full load current. The tool applies the same formula at the secondary voltage.
- Secondary fault current. It divides the secondary full load current by the impedance as a fraction. For 6 %, that means dividing by 0.06.
The tool reads no table. You enter the voltages and the impedance.
Worked example
- 500 kVA, 11 kV to 400 V, 6 % impedance, three phase. The primary full load current is 26.24 A. The secondary full load current is 721.69 A. The secondary fault current is 12,028.13 A.
Limits
The fault current assumes an infinite upstream source. A real source has impedance, so the true fault current is lower. Use the fault level calculator to include the source. The tool does not model the cable after the transformer. It does not size the protection. Impedance is a nameplate value with a tolerance.
Use the primary current to check the supply side device. Use the secondary current to check the main switch and the busbar. Take the impedance from the nameplate, because it has a tolerance.
See also: Transformer full load current, 1000 kVA at 11 kV, Transformer secondary fault current, 500 kVA and Prospective fault current at a board.
Mga tanong
Design aid ang resulta. I-verify ito laban sa kasalukuyang standard.
Ano ang ginagawa ng transformer calculator?
Iniuulat ng tool ang primary full load current, secondary full load current at secondary fault current. Gumagana ito mula sa rating sa kilovolt amperes, sa primary at secondary voltage, sa impedance percent, at sa bilang ng phase.
Aling mga input ang pinakamahalaga?
Itinatakda ng rating at ng dalawang voltage ang dalawang full load current. Itinatakda ng impedance percent ang secondary fault current: mas mababang impedance, mas mataas na fault current. Ang bilang ng phase ang naglalapat ng square root ng tatlo sa parehong current.
Ano ang mga karaniwang gotcha?
Ipinapalagay ng fault current ang infinite na upstream source, kaya worst case figure ito at sinasabi iyon ng tool sa bawat resulta. Hindi kasama ang cable at network impedance. Limitado sa 30 ang impedance percent. Nasa page address ang mga input, kaya muling nagagawa ng link ang resulta.
Mga worked example
Background
- Short-circuit withstand and the k factorThe adiabatic check in plain terms: prospective fault current, clearing time and k, worked on 25 mm² copper XLPE at 10 kA for 0.1 s.
- Arc flash basicsArcing current, incident energy, boundary and working distance explained, with three engine runs that show clearing time beating fault current every time.
Mga kaugnay na tool
- Cable size calculatorFind the smallest cable size that passes each check.AS/NZS 3008.1.2AS/NZS 3008.1.1AS/NZS 3000
- Fault level calculatorProspective fault current at a board from its source.AS/NZS 3008.1.2AS/NZS 3008.1.1AS/NZS 3000
- Transformer inrush at ang breaker nitoCheck a transformer’s switch-on inrush against its breaker.AS/NZS 3000
Nakatulong ba ito?
May tanong, o may value na mukhang mali? Makipag-ugnayan sa amin.