Overview
B143 21:1 bevel helical gearbox with a 70mm hollow bore output and 160B5 IEC motor input for compact 90° right-angle drive integration.
Optimised for industrial reliability, it delivers stable speed reduction and consistent torque transfer for everyday plant and OEM applications.
Mid reduction: Mid reduction (21:1) delivers an even speed-to-torque profile for everyday industrial duty — packaging, conveying, and automated production lines.
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: 21.00:1
- 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 | ~67 rpm |
| 2-Pole | 2800 | ~133 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 21:1 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
✔ Efficient 90° transmission in a compact bevel-helical package
✔ Quiet running and stable output thanks to precision gear cutting
✔ Designed to handle continuous-duty operation (S1) in industrial environments
✔ High load-bearing capability for demanding shaft loading conditions
✔ Ideal for variable-speed operation with VFDs where specified
✔ Durable cast iron construction for OEM and heavy-use applications
Ratio Selection Tips
- Best for: applications needing responsive motion with a torque uplift — suited to indexing, feeders, and compact right-angle machine builds.
- Selection tip: for higher output speed, low reduction is often right — just check duty, shock loading, and whether a VFD will be used for fine control.
FAQ
Will this ratio be too fast for my application?
If you need slower output speed, choose a mid or high reduction ratio. Low ratios are best when you want higher output rpm while still gaining torque.
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: indexing table or light materials handling drive where responsiveness and compact 90° layout are key
Typical Applications
- Packaging and bottling conveyors
- Sortation and distribution conveyor sections
- Inline machine modules requiring responsive motion
- Light-duty mixers or agitators with moderate torque demand
- Automated handling systems and turntables
- Materials handling drives with variable speed via VFD
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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