NU30-500-ECMA bearing: complete specifications & equivalents
The NU30-500-ECMA is a ISO 15 radial bearing sized 500 x 720 x 167 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 500 mm |
| Outer diameter D | 720 mm |
| Width B | 167 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 3800 kN |
| Basic static load rating C0 | 7350 kN |
| Fatigue load limit Pu | 560 kN |
| Reference speed (thermal) | 750 rpm |
| Limiting speed (mechanical) | 1100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 233000 g |
| Manufacturer designation | SKF NU 30/500 ECMA |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & NU3000-series range
| Bore d | 19.685 in |
|---|---|
| Outer diameter D | 28.346 in |
| Width B | 6.575 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 110 mm |
| Smallest bore in NU3000-series | 340 mm |
| Largest outer diameter in NU3000-series | 720 mm |
| Width range across NU3000-series | 133–167 mm |
| Bore position in NU3000-series (smallest first) | 3 of 3 |
| Bore above smallest NU3000-series size | 160 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NU30-500-ECMA model number is decoded
NU30-500-ECMA is the 500 mm bore entry in the NU3000 range: a 500×720×167 mm single-row caged cylindrical roller bearing with a one-piece machined brass cage, rated C 3800 kN / C0 7350 kN. The NU configuration means two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable; functionally the bearing is non-locating: the inner ring assembly can float axially in both directions and the bearing cannot support axial load. The ECMA suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. Load-per-bore for the 500 mm seat is about 7.60 kN/mm, typical of dimension series 30 (compact OD, normal width); use C0 7350 kN for static checks such as crane hook blocks standing under load. Fit practice for NU30-500-ECMA: fit the inner ring and roller assembly onto the shaft and the outer ring into the housing independently; thermal expansion is absorbed by axial float, so do not trap the inner ring between shaft shoulders. Single-row cylindrical rollers tolerate only about 3–4 minutes of arc misalignment, so verify shaft and housing alignment.
Typical equipment & failure modes
Common applications
- offshore drawworks shafts
- large rolling-mill drive trains
- marine propulsion line shafts
- heavy turbogenerator rotor supports
Known failure patterns
- inner-ring raceway spalling from overload or contamination in the line-contact hertz zone
- outer-ring raceway fatigue after extended service at loads above the catalogue L10 rating
- cage pocket wear from roller skew at light load
- polymer cage cracking or softening after sustained running above 120 °C or with incompatible lubricant
- surface distress (micro-pitting) when the EHL film falls below the composite roughness at high specific load
- edge-loading fatigue after shaft deflection beyond the 3–4 minute alignment limit
- edge loading from shaft deflection beyond the bearing alignment limit (≈ 3-4 minutes of arc for single-row CRB)
Selection pitfalls — read before you substitute
- Do not use a NU bearing where axial load must be carried — the design carries radial load only
- The dimension series 30 (compact OD, normal width) envelope is shared with the N/NU/NJ/NUP executions of 30/500, but flange configuration and axial-locating behaviour differ — quote the full SKF NU 30/500 ECMA and do not substitute rib styles without checking the shaft locating scheme.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 720 mm raceway.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 167 mm-wide ring and concentrates load.
- The 3800/7350 kN ratings are SKF catalogue 17000 (2018) values for the ECMA execution; re-verify against the current catalogue for critical drives and keep the catalogue version with the specification.
Frequently asked questions
What are the dimensions and catalogue data of NU30-500-ECMA?
SKF NU 30/500 ECMA is a single-row caged cylindrical roller bearing with 500 mm bore, 720 mm OD and 167 mm width per ISO 15. SKF lists C 3800 kN, C0 7350 kN, Pu 560 kN, reference speed 750 r/min and limiting speed 1,100 r/min, mass about 233000 g.
What does the NU designation and ECMA suffix mean?
The ECMA suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. Structurally this execution has two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable.
Can NU30-500-ECMA take axial load and locate the shaft?
No — the inner ring has no flanges, so the NU bearing is non-locating and carries radial load only; use NJ (one direction), NUP (both directions) or a paired thrust bearing for axial duty.
How does NU30-500-ECMA compare with the other executions in the same envelope?
The N/NU/NJ/NUP executions share the ISO 15 envelope and load ratings but differ in flange arrangement and axial-locating behaviour; quote the exact order number.
What limits the service life of this bearing most often?
Line-contact fatigue above the L10 rating, cage wear at light loads and high temperatures, and edge loading from misalignment beyond about 3–4 minutes of arc are the typical failure drivers.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings on 2026-09-26. Read our editorial & correction policy.