This simulator is the PLC/automation-side companion view of a variable-frequency drive: rather than modeling rectifier diode commutation, DC-bus ripple or PWM switching detail, it focuses on how a slew-limited frequency command drives an induction motor's synchronous field speed, how mechanical shaft speed trails that field under load (slip), and how the drive's torque envelope shrinks once frequency crosses the 50 Hz base point — the control-system behavior an automation engineer commissions and tunes rather than the power-electronics behavior a drives specialist designs.
• A real-time 3D model of the six-pulse rectifier context, DC-link capacitors, three-leg inverter module, ribbed induction motor with a rotating cooling fan, coupling/encoder shaft, dynamometer brake load, and drive keypad, with home view, focus-selected-part, toggleable full-enclosure cutaway, exploded view, auto-rotate, expand and show/hide labels controls, and tappable numbered components with callouts. • Seven live controls: frequency command (0–80 Hz), frequency slew rate (1–30 Hz/s), motor pole count (2/4/6 poles), dynamometer load (0–18 N·m), combined shaft inertia (0.05–0.5 kg·m²), drive enable on/off, and an "inject drive power-stage fault" toggle. • Play/pause, single-step (0.1 s) and larger-step (1 s) time controls, plus a playback-speed selector (10× slow motion, real time, 10× faster, 1 minute per second). • Start trial and Stop trial actions, with a live sequence narrative and per-component status. • Eight live metrics: applied frequency, fundamental V/Hz command voltage, synchronous field speed, mechanical shaft speed, slip relative to field, motor torque, torque envelope limit, and mechanical developed power. • A Curves & measurements tab with two charts (field rpm/shaft rpm vs. time, and developed torque/load/positive limit vs. time), the full model equations, and snapshot measurements. • An Experiments tab with four guided scenarios (ramped acceleration, higher load, above base frequency, coast after fault), a model-verification bench of independent automated checks, and a timestamped event log with a copyable trial report. • A Learn & assess tab with four guided lessons, a two-question knowledge-check quiz, and a written scope/reference statement.
The frequency command never jumps instantly to its setpoint — it slews toward the target at the configured Hz/s rate, so synchronous field speed (ns = 120f/poles) rises smoothly rather than stepping. Mechanical shaft speed is not forced to track synchronous speed; instead it obeys J dω/dt = Tmotor − Tload − 0.004ω, with motor torque itself clamped to a torque envelope: Tmotor = clamp(0.75(ωs − ω), ±Tlimit). This is why the built-in check confirms loaded shaft speed always trails synchronous speed — slip is the mechanism that produces net torque in this scalar model, not a side effect.
Pole count changes the synchronous speed for the same applied frequency (a 6-pole motor turns slower than a 2-pole motor at the same Hz), and dynamometer load plus shaft inertia together determine how quickly the motor accelerates toward its new synchronous speed once frequency changes.
Below 50 Hz the fundamental voltage rises linearly with frequency (constant V/Hz) up to a 400 V cap; above 50 Hz, voltage stays capped at 400 V while the torque envelope Tlimit = 12 × min(1, 50/f) shrinks — this is the classic constant-torque-below-base, reduced-torque-above-base behavior, reproduced by the built-in check that available torque falls once frequency exceeds 75 Hz relative to the base-frequency value. Injecting the drive power-stage fault removes torque production entirely; because inertia is still present, the shaft coasts down rather than stopping instantly, which the model verifies directly.
This is a scalar teaching torque law, explicitly not a motor equivalent-circuit or drive-sizing model — it does not include switching ripple, flux dynamics, a thermal overload model, or regenerative DC-bus calculations, and shaft rotation in the 3D view is deliberately slowed 30× for visibility while all numerical rpm and torque values use real physical time.
This PLC/automation-context model deliberately treats the rectifier, DC-link and inverter as fixed hardware context rather than simulating diode commutation, DC-bus ripple or PWM switching waveforms. Its controls and metrics are all automation-facing — frequency command, slew rate, pole count, load torque, inertia, drive enable, a drive-fault toggle, synchronous/shaft speed, slip and torque envelope — matching what an automation engineer commissions and tunes, in contrast to a rectifier/DC-link/inverter-focused sim built around power-electronics detail like field weakening and DC-bus behavior.
In this scalar model, motor torque is produced by the difference between synchronous (field) speed and actual mechanical speed — that difference, slip, is what generates the torque needed to overcome load and friction. With any nonzero load torque, some slip must persist at equilibrium, which is exactly why the built-in check confirms loaded shaft speed always sits below synchronous speed.
Below the 50 Hz base frequency, voltage rises with frequency to keep the V/Hz ratio constant, preserving full torque capability. Above 50 Hz, voltage is capped at 400 V, so the torque envelope Tlimit = 12 × min(1, 50/f) shrinks as frequency rises further — the built-in check confirms this fall in torque limit once frequency exceeds 75 Hz.
This is a representative scalar teaching model with generic parameters, not a motor equivalent-circuit or drive-sizing model. It omits switching ripple, flux dynamics, a thermal overload model and regenerative DC-bus calculations, and shaft rotation is visually slowed 30× while numerical rpm and torque use real physical time.