This simulator models a generic three-phase squirrel-cage induction motor on a dynamometer test bench. Move a held operating point across the torque-speed curve, or release the shaft to let the motor find its own mechanical equilibrium against a programmable load.
• A real-time 3D test bench — laminated stator, three-phase windings, squirrel-cage rotor, stepped shaft, rolling-element bearings, a flexible coupling, a dynamometer/load absorber, a reaction torque transducer and a torque-speed test console — 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 rotor-resistance multiplier, an ideal-dynamometer "hold speed" checkbox with a held-rotor-speed slider (0–1850 rpm), plus Start motor, Stop/coast and Reset trip actions, playback speed (10x slow to 20x fast) and 0.02 s / 0.2 s 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 (hold the normal branch at 1450 rpm, hold zero speed at starting, release the shaft to find a stable load-line intersection, and double rotor resistance to move the torque peak) 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, slip is s = (ns − n)/ns, and stator current is solved from the source voltage against the series stator impedance in combination with the parallel magnetizing and rotor branches. Air-gap power Pag = 3|I2′|²R2′/s converts to electromagnetic torque Te = Pag/ωs, and converted mechanical power is (1 − s)Pag. The mechanical state integrates J dω/dt = Te − Tload − 0.012ω, so rotor speed is always a consequence of the torque margin acting on the selected inertia, not a directly set value — unless the ideal dynamometer is holding it.
The dynamometer can impose (hold) an operating point anywhere on the curve, including points that are not naturally stable, which is why the Experiments tab has you release the shaft to see where the motor actually settles.
The torque/load/operating-point chart is calculated from the same equivalent circuit as the live model, so the plotted curve and the animated 3D bench always agree. On the normal high-speed branch a small speed decrease increases motor torque (a stable response); near and below the breakdown-torque peak that relationship can reverse, which is why some held points are not achievable as free equilibria. Rotor-resistance changes shift where that peak sits and reshape starting torque, but do not create unlimited torque.
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.
It lets you force the rotor to a chosen speed (0–1850 rpm) regardless of whether that point is a naturally stable equilibrium, so you can read off torque, current and slip anywhere on the curve. Releasing the hold lets the shaft accelerate or decelerate under the actual torque margin toward a real load-line intersection.
For this fixture, starting torque (at zero speed) is finite but below the breakdown torque peak — the maximum of the steady-state torque-speed curve. The Experiments tab includes a dedicated "Starting point" scenario that holds zero speed so you can compare the two directly.
It scales the referred rotor resistance R2′ used in the equivalent circuit, which shifts the position of the torque-speed peak and reshapes low-speed/starting torque. It does not increase the maximum torque the motor can produce — it only moves where that maximum occurs.
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.