Intermediate · P‑01
How can we start within the feeder limit?
The same pump, from rest to operating speed. Compare direct-on-line and star-delta starting.
Compare direct and star-delta starting. Check speed before transfer: less current also means less torque. A high peak and sustained overload are different phenomena.
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
- n · motor speed
- —rpm
- F1 · thermal image
- —%
- I max · whole trial
- —A
Each change starts a new 20 s cold trial. Use the cursor to review it. A 0.2 s open transition separates KY and KΔ; they never close together.
Record speed at 20 s, at 50% and 100%, with the same starter.
Recorded readings
- Choose an instrument to record a reading.
Principle, assumptions and limits
Reduced model with interpolated torque/speed and current/speed curves; J = 4 kg·m², J dω/dt = Te − Tl. Centrifugal load with friction: Tl/Tn = 0.08 + 0.92 × load × (n/1470)². In star, torque and line current are one third of delta values at the same speed. A 0.2 s open transition has no electromagnetic switching spike. F1: dθ/dt = ((I/In)² − θ)/120; trip at θ = 1.2. Dimensionless image displayed as %, not real temperature or an IEC trip class. After a trip, power is removed and the motor coasts. Independent cold trials: no hot restarting, weak supply or short-circuit model. Curves are illustrative, not identified from a manufacturer motor.
Principle reference ↗