Choosing a Worm Gearbox for Conveyor Applications
Conveyors are one of the most common applications for worm gearboxes — and also one of the easiest to get wrong if you don't account for the right factors. Here's what actually matters when sizing a gearbox for a conveyor drive.
Why worm gearboxes suit conveyors
Worm gearboxes offer high reduction ratios in a compact package, smooth low-speed output, and — importantly for conveyors — self-locking behaviour at higher ratios. This means the conveyor won't "run back" under load if power is cut, which is valuable for inclined conveyors carrying material.
Key factors for conveyor sizing
1. Required belt/roller speed
Calculate the roller RPM needed for your target belt speed (in m/min) based on roller diameter. Then use this to determine your gear ratio (see our ratio selection guide).
2. Continuous duty cycle
Most conveyors run continuously for long periods. This means Service Factor matters more here than in intermittent applications — aim for SF ≥ 1.5 wherever possible for 24/7 or near-continuous operation.
3. Starting load (breakaway torque)
A loaded conveyor at standstill needs more torque to start moving than to keep moving. If your conveyor frequently stops fully loaded and restarts, size for breakaway torque, not just running torque — this often means going one frame size larger than the running-torque calculation alone would suggest.
4. Shock loads
Conveyors feeding from hoppers, chutes, or handling irregular material (boxes, crates, uneven loads) experience shock loading. Build in extra SF margin (1.5-2.0) for these cases.
Recommended TRV models by conveyor type
| Conveyor Type | Typical Models | Notes |
|---|---|---|
| Light packaging line conveyors | TRV 30, TRV 40, TRV 50 | Low load, frequent indexing |
| Standard belt conveyors (medium duty) | TRV 50, TRV 63, TRV 75 | Continuous duty, moderate loads |
| Heavy material handling conveyors | TRV 90, TRV 110 | Shock loads, higher SF needed |
| Bulk handling / inclined conveyors | TRV 110, TRV 130, TRV 150 | Self-locking critical, high SF |
A quick worked example
Say you have a 1.1 kW motor (4-pole, 1440 RPM) driving a belt conveyor where the roller needs to run at 36 RPM:
- Required ratio: 1440 ÷ 36 = 40:1
- At 40:1, check rated torque for candidate models against your calculated output torque
- For continuous duty with occasional loaded starts, target SF ≥ 1.5
- This typically points to TRV 75 at 40:1 for a 1.1 kW motor — but always verify with the Selector for your exact numbers
Get an exact recommendation
Enter your motor power, required ratio and select "Conveyor" as the application — our Selector Tool applies conveyor-specific scoring and flags the right SF automatically.
For inclined or heavy-duty bulk conveyors where self-locking and high SF are critical, WhatsApp us your full application details — we'll help you size it correctly the first time.
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