This simulator models a six-lead induction motor rated for delta operation started through a classic star-delta (wye-delta) sequence: closed in star for reduced starting current, an open-transition dead time with both contactors open, then closed in delta for full running voltage.
• 01 / Motor laboratory: a real-time 3D test bench (housing, stator, windings, rotor, shaft, bearings, fan, guard, six-terminal connection box, main contactor K1, star contactor KY, delta contactor KΔ, timer/mechanical interlock and isolator) plus a U1/V1/W1-U2/V2/W2 six-lead terminal trainer, with home view, focus-selected-part, cutaway, exploded view, auto-rotate and expand/hide-labels controls, start, stop/coast, reset trip, apply locked rotor and release-shaft actions, run/pause toggle, 0.02 s and 0.2 s step buttons, and playback speed from 10x slow motion to 20x faster. • Settings: line-to-line supply (200-460 V), supply frequency (40-60 Hz), motor poles (2/4/6), load torque, load law (constant vs quadratic fan/pump), combined inertia, time spent in star (0.5-8 s) and the open-transition dead-time interval (0.04-0.5 s). • 02 / Curves & measurements: a torque/load/operating-point chart and a speed-and-current history chart, the underlying model equations, and live snapshot readouts of rotor speed, supply line current, torque, actual winding RMS voltage, time since start and the current-squared (I²t) integral. • 03 / Experiments: four guided scenarios (default fan-load changeover, a long visible open-transition dead time, a heavy 50 N·m constant load that can stall in star, and an early changeover at 0.5 s in star with higher inertia), plus a Verification bench of automated model checks and a timestamped event log with a copyable trial report. • 04 / Learn & assess: four lessons (check the winding voltage premise, the line-current ratio is one-third, open transition removes torque temporarily, reduced torque may be insufficient), a two-question knowledge-check quiz, and a scope-and-references statement linking to an ABB starting-methods technical reference.
The motor uses the same generic balanced fundamental-frequency induction-motor equivalent circuit as the other labs in this set (Rs=0.65 Ω, R2′=0.45 Ω, Xs=X2′=1.1 Ω, Xm=28 Ω at 50 Hz on a star-equivalent base), computing slip-dependent rotor impedance, stator current, air-gap power and torque each step, with J dω/dt = Te − Tload − 0.012ω integrating mechanical speed.
During star operation each winding sees line voltage divided by √3, which the model applies as Vwinding,Y = Vline/√3 versus Vwinding,Δ = Vline in delta. Because line current and torque both scale with the winding-voltage ratio, ideal star operation draws one-third the delta line current and produces one-third the delta torque at the same slip. The timer opens KY before closing KΔ; during the configured open-transition dead time neither contactor is closed and the model coasts under the mechanical load with zero electromagnetic torque, exactly reproducing the torque interruption of a real open-transition changeover.
The speed-and-current chart shows current dropping sharply the instant delta closes if changeover happens late (low slip, low delta inrush) versus a large current spike if changeover happens early (high slip, high delta fundamental current) — try the early-changeover experiment to see this directly. The torque/operating-point chart shows why a high constant-torque load can remain stalled throughout the star phase, since star torque is only one-third of delta torque at the same speed.
Per the model's stated scope: this is a generic representative starter, not a manufacturer-specific product, and assumes a six-lead motor rated for delta at the applied line voltage. Iron loss, saturation, unbalance, harmonics, bearing dynamics and subcycle switching transients are not solved, and the open transition has no residual-flux, contact-bounce or transient-current solver — a real changeover can create additional transients beyond what this teaching model reproduces.
In star, each winding sees line voltage divided by √3 instead of full line voltage. Because current and torque scale with the winding-voltage ratio, ideal star starting draws about one-third the delta line current — at the cost of about one-third the delta starting torque at the same slip.
The timer opens the star contactor KY before closing the delta contactor KΔ, so during the configured dead time (0.04-0.5 s) neither contactor is closed. The motor coasts under the mechanical load with zero electromagnetic torque until delta closes.
Yes. Because star torque is roughly one-third of delta torque at the same speed, the Experiments tab includes a 50 N·m constant-load scenario where the motor can remain stalled throughout the entire star phase.
It assumes a generic six-lead motor rated for delta at the applied line voltage, using representative equivalent-circuit parameters rather than a manufacturer-specific product. It does not solve iron loss, saturation, unbalance, harmonics, or the residual-flux and contact-bounce transients that can occur during a real open-transition changeover.