Motovario B103 33.07:1 Bevel Gearbox – 50mm Bore, 90B5

Overview

B103 33.07:1 bevel helical gearbox with a 50mm hollow bore output and 90B5 IEC motor input for compact 90° right-angle drive integration.

High reduction: This high reduction ratio prioritises torque multiplication and controlled output speed, suited to heavier conveyors, process machinery, and positioning applications.

---

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: 33.07:1
• 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)

---

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	~42 rpm
2-Pole	2800	~85 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 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.

---

Internal Links & Compatible Options

Same ratio, different motor input: jump to the B103 33.07:1 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: mixed-load machinery that needs dependable torque at a controlled speed — ideal for conveyors, process equipment, and continuous-duty handling systems.
• Selection tip: mid ratios are the safest all‑rounder choice — confirm shaft torque and choose service factor for start/stop cycles and shock loading.

FAQ

Is this a good general-purpose ratio?
Yes — mid reduction ratios are typically the best balance for many machines, providing controlled speed with useful torque multiplication.

How do I choose between two close ratios?
Pick the ratio that keeps your target output speed closest at the motor speed you’ll actually run (direct-on-line or via VFD), then confirm required torque and service factor.

Configuration Notes

• Input flange note: the 90B5 flange option supports larger IEC motors where extra input torque capacity is required without changing the right‑angle installation layout.
• 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: Example use: production conveyor moving mixed loads where consistent speed control and torque reserve are both important.

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.