Most gear motor guides for food plants start with washdown. That is the wrong starting point for the majority of food machinery. On a real food line, the wet, caustic, high-pressure zone is the processing area — mixers, slicers, blanchers, filling heads. One wall away sits the packaging hall: cartoners, case packers, labellers, checkweighers, film wrappers, date coders and outfeed conveyors. That hall is dry, wiped down with a damp cloth, and runs 25–300 W drives on almost every station. This guide covers that zone specifically: how to size a compact AC gear motor for food packaging and conveying equipment, what protection level is actually realistic, and where a standard industrial gear motor stops being the right answer.
Three things separate a packaging-hall drive from a processing-hall drive:
This is exactly the operating window a standard động cơ giảm tốc AC cỡ nhỏ is built for. Buying an IP69K stainless unit for a cartoner that never gets hosed down is the single most common overspend in food equipment drive selection — often two to three times the unit cost for a protection level the machine never needs.
Work backwards from the machine, not forwards from the motor. A labeller needs its applicator roller at a surface speed matched to the line; a case conveyor needs belt speed in metres per minute. Convert to output rpm first, then pick the ratio.
On our 25 W 4RK series (80 mm frame, 50 Hz), the available output speeds run from 500 r/min at 3:1 down to 5 r/min at 300:1. A packaging station almost always lands in the 20–120 r/min band.
Running torque on a horizontal conveyor is friction-dominated and roughly flat once the belt moves. Breakaway is not: a fully loaded belt that stopped mid-cycle needs two to three times the running torque to restart. Size on breakaway, then confirm that the running point sits comfortably inside the allowable load.
This is where most selection guides go wrong, because they treat torque as a property of the motor. It is not. On a fixed frame size, allowable output load rises as the ratio rises and the output speed falls. Real data from our 25 W 4RK unit:
| Tỷ lệ | Tốc độ đầu ra (vòng/phút, 50 Hz) | Tải trọng tối đa cho phép |
|---|---|---|
| 3:1 | 500 | 0.45 N·m (4.5 kg·cm) |
| 10:1 | 150 | 1.55 N·m (15.7 kg·cm) |
| 30:1 | 50 | 4.12 N·m (42 kg·cm) |
| 100:1 | 15 | 7.84 N·m (80 kg·cm) |
| 300:1 | 5 | 7.84 N·m (80 kg·cm) — gearbox limit |
Note the ceiling: past roughly 100:1 the gearbox, not the motor, sets the limit. Adding ratio stops buying you torque. If your application needs more than 7.84 N·m at 15 r/min, the answer is a larger frame — a 60 W or 90 W unit — not a deeper ratio on a 25 W.
Our small AC series carries a reversible 30-minute rating. That is a nhiệt rating, not a licence for continuous reversing. A cartoner indexing continuously in both directions is not the same load as a conveyor running one way. If the machine reverses more than roughly 10–15 times per minute on a sustained basis, add a cooling pause, drop one frame size in load, or move to a drive rated for that duty.
Be precise here, because this is where catalogue claims and factory reality diverge.
One more point buyers rarely check: the output shaft and oil seal are the weakest ingress path on any geared motor, and they are not covered by the housing IP rating in the way most people assume. Direct spray at the shaft end defeats an IP65 housing quickly. That is another argument for mechanical shielding over rating escalation.
| Station | Typical power | Why |
|---|---|---|
| Date coder, small indexing gate, film feed assist | 15–25 W | Very light load, tight space, 70–80 mm frame |
| Labeller applicator, small infeed conveyor, reject pusher | 40–60 W | Needs breakaway margin without frame growth |
| Case conveyor, carton erector flap drive | 90–120 W | Continuous running with moderate torque |
| Case packer, pallet index, heavy infeed | 200–300 W | High breakaway, larger shaft, 90 mm frame |
| Full case conveyor trunk, incline section | 400–750 W | Transition to medium-duty three-phase frames |
A 4GN 25 W right-angle unit is the usual pick for a coder or gate where the drive has to turn 90° inside a narrow frame. An inline 5RK 60 W or 6RK 120 W suits a straight conveyor run where the shaft can exit along the belt axis.
Food packaging lines change format — a 250 g pack runs slower than a 1 kg pack. Rather than fitting a variable-frequency drive to every station, our small AC series can run with a matched speed controller on the single-phase units. Two practical notes:
Be honest about the boundary. Choose something else when:
For everything else in the packaging hall — dry, dust-exposed, intermittent, 15 W to 750 W — a compact AC gear motor is the most cost-effective drive on the market, and the one that is easiest to replace when a line stops at 2 a.m.
Yes, in dry zones: packaging halls, cartoning, labelling, case packing, dry conveying and outfeed handling. It is not suitable for direct washdown or for areas sprayed with cleaning chemicals.
IP54 covers dust and splash and is enough for most packaging stations. Escalate only if the machine’s cleaning procedure puts water on the drive. If it does, shielding the drive mechanically is usually cheaper and more reliable than buying a higher IP rating.
Dust enters mainly at the shaft seal and the breathing path. Fit a shaft seal rated for dusty duty, mount the unit so the shaft points downward or horizontally rather than upward, and enclose it in a shroud with a filtered vent if the local dust load is high.
Usually 25–40 W for a short, light outfeed at low speed. Size on breakaway torque with a loaded belt, not on the running load — a 25 W unit at 30:1 gives 4.12 N·m of allowable load, which is often ample, but only if the ratio is chosen for the speed you need.
