Motor Parameters
0.30 Ω
0.50 Ω
100%
rpm
R 1 = 0.50 Ω, X 1 = 1.10 Ω, X m = 25 Ω, V L-L = 460 V, f = 60 Hz, p = 4
Advanced controls removed — these constants are used internally to produce results that better correlate with typical motor behavior.
Key Results
Torque
Rated torque: – N·m
Starting torque: – % of rated
Breakdown: – N·m at slip –
Starting Current (s=1)
– A (line)
No-load Current (s=0)
– A (line)
Loaded Speed Current
– A (line)
Loaded Power
– hp
Speed Regulation
– %
Efficiency
–
NEMA Configuration Comparison
Computed using the assumed system parameters shown above. Values are approximate and intended to illustrate typical relative behavior between NEMA rotor designs.
| Design | Starting T (N·m) | Pull-up T (N·m) | Breakdown T (N·m) | Rated T (N·m) | Rated speed (rpm) | Start I / Rated I (%) |
|---|
Note: WOUND rotor preset is excluded from this NEMA comparison. NEMA A–D are modeled as the same ~25 hp, 4-pole, 460 V motor (100 N·m rated) so the designs compare like-for-like. The smooth model has no harmonic dips, so pull-up torque equals starting torque for A, B and D; only NEMA C shows a true pull-up saddle. Values are approximate and intended to illustrate relative behavior between NEMA A–D designs.
Torque vs Speed
Stator Line Current vs Slip
Model Notes
- Per-phase approximate equivalent circuit with magnetizing branch
Xmin parallel with the rotor branch. NEMA A, B and C use a double-cage rotor: an outer cage (R2/s + jX2) in parallel with an inner cage (R2i/s + jX2i). Rotor current is forced into the high-R, low-X outer cage at standstill (high starting torque) and moves to the low-R inner cage at running speed (low slip). NEMA D and the wound-rotor preset use a single cage. - Total impedance:
Z = (R1 + jX1) + big[(jXm) parallel (R2/s + jX2)big]. - Line current magnitude computed from
I = V_phase / |Z|withV_phase = V_{L-L}/sqrt{3}for Y connection. - Air-gap power is the sum over the rotor cages,
P_ag = 3,|I_o|^2,(R2/s) + 3,|I_i|^2,(R2i/s), torqueT = P_ag / omega_{sync}, with synchronous speedomega_{sync} = 4pi f / p. - You can overlay the torque curve of every NEMA preset using the "Compare all NEMA presets" checkbox in the presets panel. Breakdown torque is the first peak of the curve (for NEMA C the locked-rotor torque can be higher than this peak), and rated torque is fixed at 100 N·m for the NEMA presets (33% of breakdown for the wound-rotor preset). A load above breakdown torque stalls the motor.
- Mechanical losses are neglected; results illustrate trends rather than exact nameplate values.