Conveyor Systems & Bulk Material Handling · Drive Engineering
Right Angle Planetary Gearbox for Conveyor Systems and Bulk Material Handling Drives
Cross-belt sorters, 90° transfer conveyors, screw feeders, and bucket elevators all share a common engineering constraint: the drive motor cannot be aligned axially with the output shaft. A right angle planetary gearbox solves this problem in a single unit, combining the 90° drive redirection with multi-stage speed reduction and torque amplification — eliminating the separate bevel stage and inline reducer that conventional designs require.
EP300R right angle gear reducer on a 90° cross-belt transfer conveyor — 8,500 Nm, IEC motor input, splined hollow output to head pulley shaft
Why Conveyor Engineers Specify Right Angle Planetary Drives
The dominant gearbox choice for conveyor head-pulley drives has historically been the parallel-shaft helical reducer — efficient, well-understood, and available in high torque ratings. However, parallel-shaft reducers require the motor to be mounted on an extended outrigger frame beside the conveyor, adding structural steel cost and creating a wider machine envelope that conflicts with walkway clearance requirements in plant installations.
A right angle planetary gearbox mounts directly between the motor and the head pulley shaft, with the motor perpendicular to the conveyor line. This configuration reduces the total drive assembly width by 40–60% compared to a parallel-shaft drive with the same ratio and torque rating — a significant advantage in dense plant layouts where conveyor centres are less than 1.2 metres apart.
The second advantage is ratio range. A single right angle planetary gearbox in the EP300R or NB300R series covers ratios from 6.9 to 9,000 within one frame size family. Matching the ratio to the belt speed and motor speed requires no secondary reducer — the planetary stages handle the full reduction in one housing.
Torque and Speed Calculation for Conveyor Drive Selection
The required gearbox output torque for a conveyor head pulley drive depends on belt tension, pulley diameter, and the wrap angle of the belt on the drive pulley. For most horizontal and slightly inclined conveyors, the effective tension formula gives a practical starting point:
Te = T1 − T2 (effective belt tension, tight side minus slack side)
Output RPM = Belt Speed (m/s) × 60 / (π × D_pulley (m))
Gear Ratio = Motor RPM / Output RPM
Example — 800 mm wide aggregate conveyor, 2.5 m/s belt speed: Effective tension Te = 18,500 N, pulley diameter 0.50 m, motor 1,450 RPM, gearbox efficiency 0.94.
Drive torque = 18,500 × 0.25 / 0.94 = 4,920 Nm. Output RPM = 2.5 × 60 / (π × 0.50) = 95.5 RPM. Required ratio = 1,450 / 95.5 = 15.2:1. The EP305R (5,000 Nm) at ratio 16:1 is the correct selection — applying a 1.25 starting load factor gives 4,920 × 1.25 = 6,150 Nm peak, within the EP305R’s peak capacity.
| Conveyor Type | Belt Width | Drive Torque | Recommended Frame |
|---|---|---|---|
| Package / parcel sorter | 400–600 mm | 1,000–3,500 Nm | NB300R / NB301R |
| Grain / fertiliser conveyor | 650–800 mm | 3,500–8,500 Nm | EP303R / EP306R |
| Aggregate / ore conveyor | 800–1,200 mm | 8,500–25,000 Nm | EP306R / EP310R |
| Heavy mine conveyor / overland | 1,200–1,800 mm | 25,000–55,000 Nm | 307 Series / EP311R–EP313R |
Drive Sprocket Integration with Right Angle Planetary Gearboxes
For conveyor applications where the gearbox output shaft connects to a secondary chain drive rather than directly to the head pulley, correct sprocket selection at the gearbox output is critical to achieving the final belt speed without introducing additional ratio error.
The gearbox output shaft — available in solid keyed, splined solid, splined hollow, and shrink-disc hollow configurations — determines the sprocket bore and hub design. For heavy-duty aggregate and mining conveyors, we recommend:
- ANSI #100 or #120 roller chain for output torques of 5,000–15,000 Nm, with a minimum 15-tooth sprocket on the gearbox output to limit chain entry angle and reduce roller impact fatigue.
- For outputs above 15,000 Nm, specify ANSI #160 or #200 chain with a hardened-tooth sprocket (HRC 50–55 on tooth face) to match the chain’s rated tensile strength of 216 kN (#160) or 356 kN (#200).
- Align the gearbox output shaft and driven shaft within 0.5 mm parallel and 0.1° angular tolerance before tensioning the chain. Misalignment at these output torque levels causes accelerated side-plate fatigue in the chain within 200–400 hours.
For conveyor and agricultural chain drive sprocket selection, see our full catalogue of
industrial drive sprockets — covering ANSI #40 through #240 roller chain, finished-bore and taper-lock hub configurations, and hardened-tooth agricultural grades.
EP300R on a grain elevator head drive — splined hollow output, ANSI #120 chain sprocket, 8,500 Nm continuous
Recommended Products for Conveyor and Bulk Material Handling Drives
Package Sorter & Light Conveyor
NB300R Series Right Angle Gearbox
1,000–500,000 Nm · Ratio 6.9–9,000 · IEC B5 motor flange · Splined or keyed output · Compact for narrow conveyor drives
Aggregate & Grain Conveyor
EP300R Series Right Angle Gear Reducer
Up to 150 kW · Hollow shrink-disc output for pulley shaft · S1 continuous rated · Reversing duty compatible
Mine Conveyor & Overland Belt
12,500 Nm · 540 kW · Up to 9,000:1 ratio · DC/AC electric brake for controlled stop on inclined belts
Technical Enquiry · Conveyor Drive Sizing
Get a Right Angle Planetary Gearbox Sized for Your Conveyor System
Provide your belt width, belt speed, effective tension or material load, and motor specification. EPG Canada returns a frame selection, ratio, and output shaft configuration within 24 hours.
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Editor：WM