This simulator opens up a generic three-phase squirrel-cage induction motor so you can inspect the frame, windings, cage rotor, cooling fan and terminal box, then run it to see how slip between the rotating field and the rotor establishes exactly the torque the load requires.
• A real-time 3D cutaway — finned motor frame, laminated stator core, three-phase stator windings, squirrel-cage rotor, stepped shaft, rolling-element bearings, shaft-mounted cooling fan, fan shroud/endshields, a six-terminal (U1/V1/W1, U2/V2/W2) connection box, and an animated rotating air-gap field arrow set — with home view, focus-selected-part, full-enclosure toggle, exploded view, auto-rotate, expand and selectable labeled components. • Motor & controller settings: line-to-line supply voltage (200–460 V RMS), supply frequency (40–60 Hz), pole count (2/4/6), load torque at base speed, load law (constant opposing torque or quadratic fan/pump demand), combined inertia, a referred-rotor-resistance multiplier, and a "lock the shaft" checkbox, plus Start motor, Stop/coast, Reset trip, Apply locked rotor and Release shaft actions, playback speed control and step buttons. • A Curves & measurements tab with a torque/load/operating-point chart, a speed-and-current history chart, the full model equations, and live snapshot readouts of rotor speed, synchronous speed, slip, line current, electromagnetic torque and converted mechanical power. • An Experiments tab with four guided scenarios (a normal loaded start, a heavier 65 N·m load, a six-pole machine at 50 Hz, and a locked-rotor run) plus a Run model checks verification bench and a timestamped event log with trial-report export. • A Learn & assess tab with four guided lessons, a two-question knowledge-check quiz and a written model-scope statement with an external reference link.
The motor is represented by a generic balanced fundamental-frequency per-phase equivalent circuit (Rs = 0.65 Ω, R2′ = 0.45 Ω, Xs = X2′ = 1.1 Ω, Xm = 28 Ω at 50 Hz, star-equivalent base, reactances scaling with frequency). Synchronous speed follows ns = 120f/poles and slip is s = (ns − n)/ns — the field speed is set entirely by electrical supply parameters, while rotor speed is a mechanical result of torque, inertia and load. At exact synchronous speed an ideal cage sees no changing fundamental flux and develops no induction torque, even though magnetizing current can still flow.
Stator current is solved from the source voltage against the series stator impedance combined with the parallel magnetizing and rotor branches. Air-gap power Pag = 3|I2′|²R2′/s splits into rotor copper loss and converted mechanical power (1 − s)Pag, and the mechanical state integrates J dω/dt = Te − Tload − 0.012ω, so a larger load generally requires greater operating slip, and excess load can stall the motor.
The torque/load/operating-point chart and the speed/current history chart are both driven from the same equivalent circuit as the animated cutaway, so a locked-rotor run (via the "lock the shaft" checkbox or the Apply locked rotor action) shows speed pinned at zero while current and rotor heating remain elevated — a direct, visual illustration of why locked-rotor duty is thermally severe.
Per the model's scope statement, this is a generic industrial equivalent circuit, not a manufacturer-specific product: iron loss, magnetic saturation, supply unbalance, harmonics, detailed bearing dynamics and subcycle switching transients are not solved, and the external geometry is representative rather than a manufacturer CAD model.
At exact synchronous speed the rotor cage sees no changing fundamental flux relative to the field, so induction torque tends to zero — there is nothing left to overcome friction and load. The simulator lets you watch slip settle at a small positive value under load rather than at zero.
The "lock the shaft" checkbox (or the Apply locked rotor action) prevents acceleration entirely. Speed stays at zero while line current and rotor heating remain high — the same electrical condition a real locked-rotor overcurrent event produces, which is why locked-rotor duty is time-limited in practice.
Synchronous speed follows ns = 120f/poles, so increasing the pole count at the same frequency reduces synchronous speed. The Experiments tab includes a six-pole scenario at 50 Hz that drops synchronous speed to 1000 rpm so you can see the effect directly.
The equivalent circuit is generic and fundamental-frequency only. It excludes iron loss, magnetic saturation, supply voltage unbalance, harmonics, detailed bearing life dynamics and subcycle switching transients, and the 3D geometry is representative industrial equipment rather than a specific manufacturer product.