This simulator models a separately excited, round-rotor synchronous motor already synchronized to the supply at matched speed. Change mechanical load and DC field excitation to see how the load angle, reactive power exchange and stability limit respond, then push the machine past its pull-out limit to trigger the teaching field-loss/out-of-step protection.
• 01 / Motor laboratory: a real-time 3D test bench (housing, stator, windings, wound-field synchronous rotor with salient pole shoes and field coils, shaft, bearings, fan, guard, six-terminal box, slip rings and carbon brushes, DC field exciter, flexible shaft coupling, dynamometer/load absorber and a rotor/field angle dial) with home view, focus-selected-part, cutaway, exploded view, auto-rotate and expand/hide-labels controls, start-synchronized-fixture, stop/coast, reset trip, apply an 80 N·m load step and remove-DC-field 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, DC field/internal EMF multiplier (0-2 pu), combined inertia and a lumped damper coefficient. • 02 / Curves & measurements: a torque-angle characteristic chart and an angle-and-speed-deviation history chart, the underlying model equations, and live snapshot readouts of rotor speed, synchronous speed, electrical load angle, electromagnetic torque, absorbed reactive power and displacement power factor. • 03 / Experiments: four guided scenarios (initializing the matched-speed synchronous-balance fixture, an excitation comparison showing reactive power reversing sign, a heavy load disturbance beyond static capability that loses stable angle, and a field-loss test that collapses torque and trips the out-of-step logic), plus a Verification bench of automated model checks and a timestamped event log with a copyable trial report. • 04 / Learn & assess: four lessons (synchronization is an initial condition, load changes angle before steady speed, excitation affects reactive exchange, there is a pull-out limit), a two-question knowledge-check quiz, and a scope-and-references statement linking to a Microchip AC induction motor application note.
This is a classical round-rotor torque-angle model with constant stator voltage and synchronous reactance Xs=8 Ω, initialized already synchronized at matched speed — it does not simulate a synchronous motor self-starting from standstill on the line. Electromagnetic torque follows Te = 3·Vphase·E·sinδ/(Xs·ωs), where E is the internal EMF set by the field-excitation multiplier and δ is the load angle. The rotor's angular position evolves via dδ/dt = polePairs·(ωs − ω), and mechanical speed integrates J dω/dt = Te + D(ωs − ω) − Tload − Bω, with the lumped damper coefficient D providing small-signal damping.
Absorbed reactive power follows Qabsorbed = 3·Vphase·(Vphase − E·cosδ)/Xs: raising the field-excitation multiplier increases E, which can flip the machine from absorbing lagging reactive power to exporting leading reactive power — a classic overexcited synchronous-motor behavior. Because the torque-angle law Te ∝ sinδ peaks at 90 electrical degrees, a sufficiently large load step or a field-loss event can push δ past the stable region, causing the rotor to lose synchronism (pole slip), at which point the model's teaching field-loss/out-of-step timer trips the machine.
The torque-angle characteristic chart shows the sinδ relationship directly, making it visible why torque capability peaks at 90° and then falls — any operating point beyond that peak is unstable. The angle-and-speed-deviation history chart shows the rotor angle settling to a new stable value after a moderate load step, or diverging when the load step or field loss exceeds what the current excitation can sustain.
Per the model's stated scope, this is a classical round-rotor torque-angle model, not a salient-pole reluctance-torque solver — the wound-field rotor's salient pole shoes are a representative physical assembly for illustration, not a source of additional reluctance torque in the equations. The field-loss/out-of-step protection is a teaching timer, not a vendor-grade out-of-step relay, and the simulator does not model a synchronous motor's line-start (induction-start) sequence — synchronization is always an initial condition here.
No. The fixture initializes the rotor already synchronized at matched synchronous speed and a feasible stable load angle. It does not model a synchronous motor self-starting from the line, which typically requires a separate induction-start winding or a variable-frequency drive.
Increasing the DC field/internal EMF multiplier raises the machine's internal EMF E. Per Qabsorbed = 3·Vphase·(Vphase − E·cosδ)/Xs, a high enough E can flip the motor from absorbing lagging reactive power to exporting leading reactive power — a classic overexcited synchronous-motor behavior you can reproduce in the excitation-comparison experiment.
Because torque follows Te ∝ sinδ and peaks at 90 electrical degrees, losing field excitation or applying too large a load disturbance can push the load angle past the stable region. The rotor then loses synchronism (pole slips), torque collapses, and the model's teaching field-loss/out-of-step timer trips the machine.
No — it is a simplified teaching timer meant to illustrate the consequence of losing synchronism, not a vendor-grade out-of-step or loss-of-field relay used in industrial protection schemes.