Overview
B103 50.24:1 bevel helical gearbox with a 50mm hollow bore output and 80B5 IEC motor input for compact 90° right-angle drive integration.
Engineered for continuous-duty operation, this configuration delivers dependable torque transfer and smooth running under load.
High reduction: This high reduction ratio prioritises torque multiplication and controlled output speed, suited to heavier conveyors, process machinery, and positioning applications.
Built for long service life, this gearbox supports consistent performance for automation and materials handling duties.
With its compact 80B5 flange input, this setup suits space-conscious installations using IEC frame motors, while still delivering industrial-grade power density and durability.
As part of the modular Motovario B103 bevel helical gearbox range, this unit supports flexible mounting positions, straightforward IEC motor compatibility, and proven long-term reliability for industrial service.
Need the non-standard 45mm bore option?
If your application requires a 45mm output bore instead of the standard 50mm, we can supply this as a non-standard configuration. View available B103 options and request the 45mm version here: Motovario B103 Gearbox.
Key Specifications
- Series: B Series – Bevel Helical Gearboxes
- Model: B103
- Reduction Ratio: 50.24:1
- Output Bore: 50mm Hollow Bore
- Motor Input: 80B5 IEC Flange
- Housing Material: High-strength cast iron
- Gear Type: Spiral bevel + hardened helical stage
- Mounting Positions: B3 Horizontal Mount
- Duty Rating: Suitable for continuous industrial operation (S1)
Manufactured to IEC dimensional standards for seamless compatibility with IEC frame motors and inverter-driven (VFD) applications.
Output Speed (4-Pole vs 2-Pole Motors)
Calculated nominal output speed using a standard IEC motor:
| Motor Type | Input Speed (rpm) | Estimated Output Speed (rpm) |
|---|---|---|
| 4-Pole | 1400 | ~28 rpm |
| 2-Pole | 2800 | ~56 rpm |
Need torque confirmation? Output torque depends on motor power (kW), gearbox efficiency, and service factor. Use our Gearbox Service Factor Calculator or contact us for verified torque figures.
Motor Input Chart (IEC Flange Details)
This gearbox is supplied with a 80B5 IEC motor input. Confirm flange compatibility below:
| Motor Input | IEC Standard | Input Dimensions |
|---|---|---|
| 80B5 | IEC 60072 / IEC 60034 (B5 flange) | Ø200 × 19 |
If you’re unsure whether your motor is B5 or B14, contact our technical team for compatibility confirmation.
Internal Links & Compatible Options
Same ratio, different motor input: jump to the B103 50.24:1 variant you need (50mm bore).
Need a different ratio? Explore the closest B103 50mm bore ratios above and below this version.
More B103 options: Browse all Motovario B103 gearbox ratios
Explore the full B Series range: Motovario B Series bevel gearboxes
Helpful calculators:
Gearbox Ratio & Speed Calculator |
Output Torque Calculator
Performance & Design Features
✔ Space-saving 90° bevel layout for compact machine designs
✔ Strong torque multiplication with stable, controlled output speeds
✔ Precision-machined spiral bevel gearing for smooth, low-noise power transfer
✔ Heavy-duty taper roller bearings for high radial and axial load handling
✔ Well suited to inverter (VFD) driven motors and variable-speed control
✔ Rigid cast iron housing built for OEM and continuous-duty operation
Ratio Selection Tips
- Best for: torque-focused drives with reduced output speed — ideal for heavier conveyors, mixers, and load-handling equipment that must start and run smoothly under load.
- Selection tip: for torque-heavy duties, high reduction helps — verify duty cycle, heat dissipation, and whether backdriving resistance is required.
FAQ
Does a high ratio increase torque a lot?
Yes — high reduction significantly multiplies torque and reduces output speed, improving stability under load. Always confirm shaft torque and gearbox service factor.
Do I need braking or a soft start?
Often recommended for heavier loads. A VFD ramp or soft starter helps reduce shock loading during start/stop, and braking may be needed for controlled stopping.
Configuration Notes
- Input flange note: the 80B5 IEC input is a popular all‑round configuration, offering increased input torque capacity while keeping a compact gearbox footprint.
- Output bore note: the 50mm hollow shaft bore is a common industrial size for conveyors and handling equipment, offering a strong shaft interface for torque transmission.
- Application example: mixer/agitator drive requiring stronger torque at a controlled output speed for consistent process results.
Typical Applications
- Conveyor and line-shaft drive systems
- Automated production and assembly lines
- Food and beverage processing machinery
- Materials handling and logistics equipment
- Pumps, mixers, and agitator drives
- OEM machine and equipment builds
Need help selecting the correct ratio, bore size, or motor input?
Contact our gearbox specialists for sizing assistance, torque verification, and availability confirmation.
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