Rossi A Series Worm Gearmotors & Speed Reducers
The Rossi A Series Worm Gearmotor Platform (featured model: MR A 63 UO3A 1.5 kW 1:30 Ratio) represents Rossi's flagship universal right-angle drive system, engineered specifically for high reliability, smooth motion, and extreme structural rigidity in automated conveyors, packaging machinery, food processing, mixers, and general material handling. Manufactured around Rossi's signature **monolithic (single-piece) cast-iron housing**, A Series gearboxes eliminate split-casing joints and gasket distortion, achieving zero oil leakage and high resistance to heavy overhung loads. Featuring case-hardened ground alloy steel worm shafts paired with high-tin bronze worm gear rims, these units deliver optimized sliding contact efficiency, silent power transmission, and self-locking capabilities on high ratios. Covering continuous torque output ratings from 30 Nm up to 19,000 Nm across 14 frame sizes (Size 32 to Size 250) and gear reduction ratios from 7:1 to 16,000:1 (in combined double-worm configurations). WE DRIVE HONGKONG LIMITED supplies 100% original Rossi A Series gearmotors, replacement units, and exact technical model code decoding across global industrial applications.
Technical Specifications
| Featured Model | MR A 63 UO3A - 28x250 - 30 (Size 63, 1.5 kW 4-Pole 230/400V Motor, 1:30 Reduction Ratio, Universal Monolithic Housing, Hollow Shaft) |
|---|---|
| Brand / Manufacturer | Rossi S.p.A. (Moog Group) |
| Product Series | A Series Universal Monolithic Worm Gearmotors (MR A) & Speed Reducers (R A) |
| Frame Sizes Covered | Size 32, 40, 50, 63, 64, 80, 81, 100, 125, 126, 160, 161, 200, 250 (Cast Iron Construction) |
| Output Torque Range | 30 Nm to 19,000 Nm (265 lb-in to 168,000 lb-in Continuous Output Torque) |
| Gear Reduction Ratios | Single Reduction: 7:1 to 100:1; Combined Double Worm Reduction: 100:1 to 16,000:1 |
| Housing Architecture | Rigid Single-Piece Monolithic Cast Iron Housing with Integral Feet & Flange Mounting Options |
| Shaft & Coupling Options | Keyed Hollow Shaft Standard, Solid Single/Double Shaft, IEC Normalized Motor Coupling (B5/B14) |
Documentation & Resources
Rossi A Series Frame Size, Power & Torque Selection Matrix
Complete selection matrix for Rossi A Series worm gearmotors and speed reducers. Review frame sizes, typical motor power ratings, maximum allowable torque outputs, standard ratios, and model codes:
| Rossi Frame Size | Motor Power Range | Max Output Torque (Nm) | Single Stage Ratios (i) | Rossi Model Code Example | Output Shaft Bore |
|---|---|---|---|---|---|
| Size 32 / 40 | 0.12 kW - 0.55 kW | 110 Nm | 7, 10, 15, 20, 28, 40, 56, 80 | MR A 40 UO3A - 14x138 - 20 | 19 mm / 24 mm Hollow |
| Size 50 / 63 | 0.75 kW - 2.2 kW | 380 Nm | 7, 10, 14, 20, 28, 40, 56, 80 | MR A 63 UO3A - 28x250 - 30 | 25 mm / 30 mm Hollow |
| Size 80 / 81 | 1.5 kW - 4.0 kW | 900 Nm | 7, 10, 14, 20, 28, 40, 56, 80 | MR A 80 UO2A - 38x300 - 15 | 35 mm / 40 mm Hollow |
| Size 100 / 125 | 4.0 kW - 11.0 kW | 2,500 Nm | 7, 10, 14, 20, 28, 40, 56, 80 | MR A 100 UO2A - 42x350 - 20 | 45 mm / 50 mm Hollow |
| Size 160 / 161 | 7.5 kW - 22.0 kW | 6,000 Nm | 7, 10, 14, 20, 28, 40, 56, 80 | MR A 160 UO2A - 48x350 - 28 | 60 mm / 70 mm Hollow |
| Size 200 / 250 | 15.0 kW - 45.0 kW | 19,000 Nm | 7, 10, 14, 20, 28, 40, 56, 80 | R A 250 UP1A - 80 | 90 mm / 100 mm Solid/Hollow |
Conventional Split-Case Worm Reducer to Rossi A Series Replacement Guide
Direct replacement guide for upgrading conventional split-housing worm gearboxes to Rossi A Series monolithic cast-iron units:
| Conventional Worm Reducer | Common Failure Modes | Current Rossi A Series Equivalent | Key Performance & Monolithic Advantages |
|---|---|---|---|
| Standard Aluminum / Split Cast Worm Gearbox | Split-casing oil leaks, housing flex under overhung load | Rossi MR A 50 / MR A 63 100% Monolithic Upgrade | Single-piece monolithic cast-iron frame completely prevents oil leaks and casing distortion. |
| Standard 1.5 kW Right-Angle Worm Drive | Rapid bronze wheel tooth wear, high operating temperature | Rossi MR A 63 UO3A High Dynamic Efficiency | Precision ground worm profile and high-tin bronze wheel extend wear life under heavy duty. |
| Heavy Duty Conveyor Worm Reducer | Frequent shaft oil seal leaks due to shaft runout | Rossi MR A 80 / MR A 100 Heavy Load Support | Integrated heavy-duty tapered roller bearings support high radial and axial thrust loads. |
Expert Technical Sourcing & System Integration Notes
When replacing older right-angle drives or retrofitting compact industrial conveyors, agitators, packaging lines, or indexing tables, switching to Rossi A Series worm gearmotors delivers immediate operational advantages: complete elimination of split-housing oil leaks via monolithic cast-iron construction, high mechanical service factors, silent power transmission, universal mounting versatility, and full compliance with IEC motor standards. Simply provide us with your existing Rossi nameplate designation or complete specification code (e.g., MR A 63 UO3A - 28x250 - 30 or R A 80 UP1A - 14), and our technical engineering team will deliver a 100% compliant replacement specification and proposal.
Core Benchmark Model Standard Configurations
- MR A 40 UO3A (0.37 kW 1:20 Ratio)
- MR A 50 UO3A (0.75 kW 1:15 Ratio)
- MR A 63 UO3A (1.5 kW 1:30 Ratio)
- MR A 80 UO2A (3.0 kW 1:15 Ratio)
- MR A 81 UO2A (4.0 kW 1:20 Ratio)
- MR A 100 UO2A (5.5 kW 1:20 Ratio)
- MR A 125 UO2A (11.0 kW 1:28 Ratio)
- R A 50 UP1A (Solid Input Reducer)
- R A 63 UP1A (Solid Input Reducer)
- R A 80 UP1A (Solid Input Reducer)
- Rossi Size 50 Monolithic Worm Reducer
- Rossi Size 63 Monolithic Worm Reducer
- Rossi Size 80 Monolithic Worm Reducer
- Rossi Size 100 Monolithic Worm Reducer
- Rossi A Series Combined Double Worm
- Rossi Worm Reducer with Torque Arm
- Rossi A Series Solid Output Shaft
- Rossi A Series IEC Flange Coupling
- Rossi Monolithic Cast Iron Worm Unit
- Rossi Quiet Right Angle Gearmotor
