P = T·2πn/60; P = Fv
SI: P watts, T N·m, n RPM, F newtons, v m/s. Mechanical power at the same shaft/load point.
Tập 1, Chapter 2, printed pp. 16–20; independently derived work/time relationship. Existing ValiCalc power expressions retained.
VALICALC / MECHANICAL ENGINEERING SUITE / DS03
Multi-Stage Powertrain Design Sheet
Describe the stages in their physical order. A ratio or efficiency change recalculates the entire shaft table; rotation direction is separate from the direction of power flow.
Verified mathematical models with explicit assumptions. Component capacity and applicability are shown as separate checks.
Labeled example inputs • SI calculations • Project revision 0 • No account or cloud upload
01 / ENGINEERING INPUTS
Define the operating point
rpm
kW
Stages
02 / CALCULATE → SELECT → RECALCULATE
Calculation & checks
Final shaft RPM · signed rotation
-250 rpmFinal shaft power
6.4125 kWFinal shaft torque · signed rotation
-244.93946 N·mCumulative efficiency
85.5 %Total loss
1.0875 kWTotal reduction ratio
6 :1| Shaft | RPM · signed | Power (W) | Torque (N·m) · signed | Stage η | Cumulative η | Loss (W) |
|---|---|---|---|---|---|---|
| 0 | 1,500 | 7,500 | 47.746483 | 1 | 1 | 0 |
| 1 | 500 | 7,125 | 136.077476 | 0.95 | 0.95 | 375 |
| 2 | -250 | 6,412.5 | -244.939457 | 0.9 | 0.855 | 712.5 |
Criterion-specific verification
- PASSED · Serial energy balance
Pin − Pout − Σloss = -2.2737367544323206e-13 W.
- UNKNOWN · Shaft/component capacity
This kinematic shaft table does not rate the actual components.
Method and calculation trace
n out = n in / i; P out = η P in; T = P/ω. Negative RPM and torque denote rotation only; P remains positive in the entered stage sequence.
In inverse power mode, P input = P output / Πη. Linked steady DS02 cases are recalculated from the same project on every input change. Transient cases require a coupled inertia model and are blocked here.
Assumptions & scope
Serial steady positive power flow only. Reversed rotation does not model backdriving or regenerative efficiency. No branching, differential or planetary topology here.
Efficiencies are user-entered operating assumptions. Shaft-load, gear strength and lubrication checks remain separate.
Worked example
7.5 kW at 1500 RPM through 3:1/95% then 2:1/90% gives 250 RPM, 6.4125 kW output and 1.0875 kW total loss.
Calculation methods and sources
n out = n in/i; P out = ηP in; η total = Πη; T out = ηiT in
Serial passive motoring power flow; 0 < η ≤ 1. Rotation signs do not imply a reversible loss model.
Tập 1, 2.15–2.18 and 3.23–3.25; independent conservation-of-energy derivation.
Textbook references identify the method context. Historical numerical catalog, material and service-factor tables have not been copied or treated as current product ratings.
Related calculators and references
Existing component-selection Jobs → · All mechanical worksheets →
Common questions
Does this approve a real component?
No. The worksheet separates mathematical results from criterion-specific checks. Actual motor, belt, sprocket and chain capacity need applicable current manufacturer data and installation review.
What changes after choosing a physical size?
The worksheet recalculates the outputs and geometry from the entered actual dimensions or discrete tooth/link count. Dependent checks are reevaluated; previously saved results are not restored as approvals.