Selected Motor
Pre-filled from the product catalog. Open the catalog to choose a different model.
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Brand: –
Series: –
Model: –
Power: –
Rated T: –
Peak T: –
Speed: –
J: –
Amplifier: –
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Selection Guide
How to choose a servo motor: apply the four selection conditions, then run the calculations.
Four selection conditions
- Motor max speed > required max speed.
- Rotor inertia matches load inertia (JL/JM within limit).
- Continuous load torque < rated torque.
- Peak (acceleration) torque < maximum torque.
Three calculation steps
- 1 · Inertia matching: compute JL and check JL/JM.
- 2 · Speed: compute load and motor speed from lead/diameter and ratio.
- 3 · Torque: compute steady and acceleration torque; verify RMS and peak.
Always check three things: speed (rpm), torque (N·m) and inertia (J).
Oversizing wastes cost; undersizing causes stall or poor response. Use RMS torque for thermal sizing and peak torque for the acceleration event.
Selection Workflow
Two widely used supplier methods, plus a general checklist. Apply them after the torque / inertia calculations.
Mitsubishi 5-step method
- Maximum speed: Nmax ≥ Vm·i / Pb.
- Inertia match: JM·2.5 > JL.
- Acceleration peak: Tmax = 2π·N·(JM+JL)/(60·Ts) + TF ≤ 80% of drive maximum.
- RMS (thermal): Trms ≤ 80% of rated torque.
- Overload time: continuous overload ≤ motor allowed time.
FANUC 6 selection conditions
- No-load running torque < 50% of continuous rated torque.
- Acceleration / deceleration time within motor capability.
- Frequent-positioning RMS torque ≤ rated torque.
- Periodic load-fluctuation RMS ≤ rated torque.
- Maximum cutting-torque duty cycle satisfied.
- Load inertia ≤ 3× motor inertia (Mitsubishi recommends ≤ 2.5×).