NEMA 17 vs NEMA 23: OEM Selection Guide

NEMA 17 and NEMA 23 are both common in industrial motion systems, but they solve different load problems. Choosing by frame size alone often causes overheating, missed steps, or unnecessary BOM cost.

Quick Positioning

• NEMA 17: compact footprint, moderate torque, preferred when space and weight are constrained.
• NEMA 23: higher torque reserve, stronger inertia handling, preferred for heavier loads and higher dynamic demand.

Decision Criteria That Matter

1. Torque Margin

Use your required working torque and include safety margin for acceleration and transient load. A practical target is to keep steady-state torque demand comfortably below motor capability at operating speed.

2. Speed-Torque Curve, Not Holding Torque

Holding torque alone is not enough. Compare the curve at your real RPM range and driver current setting. A motor that looks strong at standstill can still underperform at speed.

3. Thermal Envelope

Higher current settings increase torque but also raise coil temperature. Account for ambient temperature, enclosure ventilation, and duty cycle before locking current.

4. System Mechanics

• Lead screw pitch
• Gear ratio
• Load inertia
• Required positioning time

These factors can move the better choice from NEMA 17 to NEMA 23, or vice versa.

5. Total Cost, Not Unit Price

Evaluate:

• Motor unit price
• Driver class requirement
• Mechanical redesign cost
• Failure/rework risk from under-sized torque

An apparently cheaper motor can become expensive when integration risk is included.

Recommended Validation Flow

1. Define load case and motion profile.
2. Simulate required torque across speed range.
3. Select candidate NEMA 17 and NEMA 23 models.
4. Run prototype tests on temperature rise, repeatability, and noise.
5. Freeze specification after validation data, not assumptions.

For model matching support, send your load and motion data to [email protected]. You can also review our NEMA frame motor options.