kVAから アンペア 計算機
皮相電力を電流に変換します。総容量がkVAで定格される発電機、変圧器、産業用配電盤のサイジングに不可欠です。
配電分析
皮相電力 → 電流
配電盤用に相ごとに計算された電流です。
変換式
kVAからアンペアへの変換は、単相システムと三相システムで異なります。
単相AC
I = (kVA × 1000) ÷ V kVAにはすでに力率が含まれているため、PF入力は不要です。UPSシステム、発電機、単相変圧器に使用されます。
三相AC
I = (kVA × 1000) ÷ (√3 × V) 三相皮相電力は√3（1.732）係数を用いた線間電圧を使用します。産業用発電機や変圧器の標準です。
How to Convert kVA to Amps
kVA (kilovolt-amperes) is a measure of apparent power — the total power a source must supply, including both real work and reactive power. Unlike kW which measures only real power, kVA is the rating used for generators, UPS systems, and transformers because these devices must supply whatever current is demanded regardless of the load's power factor.
kVA vs. kW: The Key Difference
kW = kVA × Power Factor. A 10 kVA generator powering a load with 0.8 PF delivers only 8 kW of real power. Always size generators and UPS units in kVA — the kW figure alone will lead to undersizing if your loads have poor power factors.
Where kVA Ratings Are Used
- Generators: All generator output capacity is rated in kVA. A 20 kVA generator at 0.8 PF produces 16 kW of real power.
- UPS Systems: Uninterruptible power supplies use kVA ratings. Match the kVA rating to your total load's apparent power, not just its watt draw.
- Transformers: Transformer capacity is always in kVA. The secondary current rating determines what wire gauge and protection you need.
- HVAC Equipment: Large commercial air conditioning units may publish kVA demand for electrical planning purposes.
Step-by-Step Conversion
- Find the kVA Rating: Read it from the generator, UPS, or transformer nameplate.
- Note the Output Voltage: Single-phase systems typically output 120V or 240V; three-phase at 208V, 240V, or 480V.
- Select the Phase Type: Use the single-phase or three-phase formula based on your system.
- Calculate: The result is the maximum continuous current the device can supply — use it to select cables and protection devices.