Intermediate · P‑01
Why more amps without more kW?
Measure pump P‑01 in steady operation. Connect voltage, current, power and compensation.
Compare P, Q and S, then supply and motor currents. C1 compensates at the switchboard: it does not reduce shaft work.
P‑01 / M1 · 22 kW shaft · 400/690 V Δ/Y · 50 Hz · 1,470 rpm · η 0.90 · cos φ 0.82
Readings
- I · supply line current
- —A
- P · active input power
- —kW
- Q · supply reactive power
- —kvar
- Supply power factor
- —
Record current at 50% and 100%, with the same compensation.
Recorded readings
- Choose an instrument to record a reading.
Principle, assumptions and limits
RMS values, three phases separated by 120°, balanced sinusoidal steady state. Rated delta operation at 400 V: Uwinding = Uline, Iwinding = Imotor/√3. In star, Uwinding = Uline/√3. P = 22 × load / 0.90; Qm = P tan(acos(0.82)); Qc = C1 × (U/400)²; Q = Qm − Qc; S² = P² + Q²; I = 1,000 S/(√3 U). Motor efficiency and power factor are held constant, including at reduced load. C1 is at the switchboard, not on an isolated motor. No unbalance, harmonics, capacitor switching transient or self-excitation model.
Principle reference ↗