Motovario B103 144.69:1 Bevel Gearbox – 50mm Bore, 90B5

Overview

B103 144.69:1 bevel gearbox with a 50mm hollow bore output and 90B5 IEC motor input for compact 90° right-angle drive integration.

Very high reduction: With very high reduction at 144.69:1 you achieve maximum torque and ultra-low output speed for demanding duty such as heavy conveyors, rotary valves, and high-inertia applications requiring stable motion.

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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.

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Key Specifications

• Series: B Series – Bevel Helical Gearboxes
• Model: B103
• Reduction Ratio: 144.69:1
• Output Bore: 50mm Hollow Bore
• Motor Input: 90B5 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)

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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	~10 rpm
2-Pole	2800	~19 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.

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Motor Input Chart (IEC Flange Details)

This gearbox is supplied with a 90B5 IEC motor input. Confirm flange compatibility below:

Motor Input	IEC Standard	Input Dimensions
90B5	IEC 60072 / IEC 60034 (B5 flange)	Ø200 × 24

If you’re unsure whether your motor is B5 or B14, contact our technical team for compatibility confirmation.

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Internal Links & Compatible Options

Same ratio, different motor input: jump to the B103 144.69:1 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

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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

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Ratio Selection Tips

• Best for: maximum torque and very low output speed — ideal for heavy conveying, bulk handling, rotary valves, and high-inertia loads that demand stable, controlled motion.
• Selection tip: very high ratios are for maximum torque — verify load inertia, stopping requirements, and whether braking (mechanical or VFD) is needed to control overrun.

FAQ

Is a very high ratio suitable for heavy conveyors?
Yes — very high ratios are commonly used where maximum pulling power and stable, low-speed motion are required.

Do I need to worry about stopping/overrun?
Yes — with high inertia loads, consider braking (mechanical brake or VFD braking) and confirm holding/overrun requirements to keep motion controlled.

Configuration Notes

• Input flange note: the 90B5 IEC input is suited to higher-power motor pairings, improving input torque handling for continuous-duty industrial operation.
• Output bore note: with a 50mm bore, this gearbox suits many standard shafting setups, providing a robust interface for continuous-duty power transfer.
• Application example: bulk handling drive where controlled start/stop and high pulling power are critical.

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

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Need help selecting the correct ratio, bore size, or motor input?
Contact our gearbox specialists for sizing assistance, torque verification, and availability confirmation.