Overview
B143 77.12:1 bevel helical gearbox with a 70mm hollow bore output and 160B5 IEC motor input for compact 90° right-angle drive integration.
Engineered for continuous-duty industrial service, it provides smooth power transmission, stable output speed control, and dependable torque delivery in demanding environments.
High reduction: High reduction at 77.12:1 focuses on torque multiplication and controlled output speed, making it well suited to heavier conveying, process machinery, and positioning applications.
This configuration includes a 70mm hollow output bore and a 160B5, providing dependable speed reduction and consistent torque delivery for conveyors, automation lines, packaging machinery, and OEM equipment builds.
With its larger 160B5 flange input, this version is intended for bigger IEC frame motors, offering higher input capacity and wider motor compatibility while maintaining a compact 90° installation footprint and proven heavy-duty reliability.
As part of the modular Motovario B143 bevel helical gearbox range, this unit supports multiple mounting orientations, straightforward IEC motor fitment, and dependable long-term performance for continuous industrial service.
Need the non standard 65mm bore option?
If you need an output bore other than the standard 70mm, alternative configurations may be available subject to supply. View the B143 range and request your required bore option here: Motovario B143 Gearbox.
Key Specifications
- Series: B Series – Bevel Helical Gearboxes
- Model: B143
- Reduction Ratio: 77.12:1
- Output Bore: 70mm Hollow Bore
- Motor Input: 160B5 IEC Flange
- Housing Material: High-strength cast iron
- Gear Type: Spiral bevel + hardened helical stage
- Mounting Positions: B3 Mount
- Duty Rating: Suitable for continuous industrial operation (S1)
Manufactured with hardened, precision-ground gear geometry to improve efficiency and help minimise heat build-up under continuous load.
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 | ~18 rpm |
| 2-Pole | 2800 | ~36 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 160B5 IEC motor input. Confirm flange compatibility below:
| Motor Input | IEC Standard | Input Dimensions |
|---|---|---|
| 160B5 | IEC 60072 / IEC 60034 (B5 flange) | Ø350 x 42 |
If you’re unsure whether your motor is B5 or B14, contact our technical team and we’ll confirm compatibility.
Internal Links & Compatible Options
Same ratio, different motor input: jump to the B143 77.12:1 variant you need (70mm bore).
Need a different ratio? Explore the closest B143 70mm bore ratios above and below this version.
More B143 options: Browse all Motovario B143 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 right-angle gearbox design for tight machine envelopes
✔ Spiral bevel gear geometry promotes smooth, efficient 90° power transfer
✔ Strong bearing arrangement for radial/axial load capacity at the output shaft
✔ Cast iron housing resists vibration and supports continuous-duty use
✔ Compatible with inverter control for adjustable speed processes
✔ Built for reliable long-term torque transmission in industrial service
Ratio Selection Tips
- Best for: torque-focused applications with reduced output speed — ideal for heavier conveyors, process machinery, and higher inertia loads.
- Selection tip: high reduction is ideal when torque is priority; confirm motor power and thermal conditions, especially if running slowly for long periods.
FAQ
Will this ratio be too slow?
If you need faster output speed, choose a low or mid reduction ratio. High ratios are used when torque and load capacity matter most.
Can I run this with a VFD?
Yes — a VFD is ideal for accurate speed control. For long periods at very low motor speeds, ensure adequate motor cooling if running at reduced frequency.
Configuration Notes
- Input flange note: the 160B5 IEC input suits larger IEC motors, increasing input capacity and expanding motor compatibility for heavier-duty applications.
- Output bore note: the 70mm hollow bore supports larger shaft interfaces and higher loading, providing a rigid, secure connection for torque transmission.
- Application example: heavy-duty conveyor drive where pulling force and stability are required
Typical Applications
- Bulk handling conveyors and transfer stations under load
- Screw conveyor and dosing equipment requiring strong pulling force
- Process drives where output speed must be controlled and stable
- Heavy-duty accumulation zones and roller conveyor drives
- High-inertia applications with reliable torque reserve
- Continuous-duty machinery sized for service factor margin
Need help selecting the correct ratio, bore size, or motor input?
Contact our gearbox specialists for sizing support, torque checks, and availability confirmation.
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