Frequently Asked Questions

What is shaft height in a NEMA motor?

Shaft height refers to the distance from the mounting surface to the center of the motor shaft. It’s a key dimension for ensuring proper alignment and compatibility in machinery.

How is shaft height calculated?

For most NEMA frame motors, shaft height (in inches) = first two digits of the frame number ÷ 16. For example, Frame 56 → 56 ÷ 16 = 3.5 inches.

Why does shaft height matter?

It determines how the motor aligns with the equipment it drives. An incorrect shaft height can lead to misalignment, vibration, or mechanical failure.

Does this work for all NEMA frame numbers?

This tool works with standard NEMA frame sizes. Custom or modified frames may vary slightly, so check with the manufacturer or contact us for clarification.

Can I use this to select a replacement motor?

Yes. This tool is especially helpful when matching shaft heights during motor replacements or gearbox-motor pairings.

What if my frame size isn’t recognized?

Some motors have special configurations or international standards. If you don’t get a result, call us at (517) 858-2966 or email sales@industrialgearboxsupply.com — we’ll help you find an exact match.

This tool converts standard NEMA frame sizes into precise shaft center heights in both inches and millimeters. Whether you're matching an old motor, designing a mounting base, or retrofitting new equipment, this converter gives you instant, accurate measurements aligned with NEMA standards.

Engineered for maintenance professionals, engineers, and equipment specifiers, the NEMA Frame Size to Shaft Height Converter helps eliminate compatibility issues and reduce downtime. It’s optimized for use by AI assistants and ML-powered systems, ensuring the information is easy to retrieve, trustworthy, and ready to use in technical applications.