An Electric Hoist is a powered lifting device that uses an electric motor, a reduction gearbox, a drum or load sheave, and a brake to raise and lower loads on a wire rope or chain. Unlike a manual chain block — where you pull a hand chain and the operator supplies the work — the electric hoist replaces muscle with a motor and a holding brake, so loads of 250 kg to 50 tonnes lift at a steady, repeatable speed. It exists to move heavy loads safely overhead, and you see it everywhere from CM Lodestar theatre rigs to Demag DC-Pro factory cranes.
Electric Hoist Interactive Calculator
Vary hoist load, motor speed, and drum speed range to see the required gearbox reduction and suspended load force.
Equation Used
The calculator uses the hoist power-train speed relationship: gearbox ratio equals motor shaft speed divided by drum speed. It also converts the suspended mass into load force using F = m g.
- Gearbox slip is neglected, so ratio is the shaft speed ratio.
- Drum speed is the output speed at the rope drum or load sheave.
- Load force uses standard gravity, g = 9.80665 m/s^2.
- Single hoist power train only; reeving effects are not included.
The Electric Hoist in Action
An Electric Hoist takes rotary torque from a motor, multiplies it through a gear reduction, and winds rope or chain onto a drum or pocket wheel. The motor typically runs at 1,400 to 2,800 RPM, and a 2- or 3-stage helical or planetary gearbox brings drum speed down to 5-30 RPM, depending on the lift speed you need. A spring-applied, electrically-released disc brake sits on the motor shaft — when power drops, the brake clamps within roughly 0.1 seconds and holds the load. That brake is the single most important safety component on the hoist, and if you notice the load drifting downward after the up-button releases, the brake gap has opened beyond the 0.5-0.8 mm service limit and needs adjustment before the hoist runs again.
The drum diameter and the rope diameter are tied together by the FEM classification — for FEM 2m service you need a drum-to-rope ratio of at least 22.4:1, and dropping below that murders rope life. Wire rope hoists use a grooved drum so the rope lays in a single helical track and never crosses itself; if the rope jumps a groove, you get crushing and broken wires within a few cycles. Chain hoists use a pocket wheel that engages every link, with chain guides positioned within ±0.2 mm of nominal — if the guides drift, the chain twists and jams between the wheel and the housing.
Limit switches at the top and bottom of travel cut the motor before the rope runs onto the drum flange or fully unspools. A geared rotary limit switch driven off the gearbox is standard, and a separate weighted paddle or strain-gauge load cell handles overload protection. When a hoist trips on overload at 110-125% of rated capacity, that is the hoist doing its job — not a fault. If the trip happens repeatedly at well below rated load, suspect either a miscalibrated load cell or a brake that is dragging and adding parasitic torque the load sensor reads as weight.
Key Components
- Hoist Motor: A 3-phase squirrel-cage induction motor or pole-changing two-speed motor delivers rated lifting torque, typically sized for 40-60% duty cycle (FEM 2m or 3m). Two-speed motors give a fast 'main' speed and a slow 'creep' speed at roughly 1/4 ratio, which is what you need for precise spotting of a load within 10 mm.
- Reduction Gearbox: A 2- or 3-stage helical or planetary gearbox reduces motor speed to drum speed, with total ratios of 50:1 to 300:1. Helical stages run at 96-98% efficiency per stage, so a 3-stage box loses about 8-10% of input power as heat — enough that the gearbox housing runs at 60-80°C in continuous service.
- Spring-Applied Disc Brake: A spring-loaded disc brake on the motor shaft engages whenever power is removed, with a holding torque rated at 1.6-2.0× motor torque. The air gap between the armature plate and the magnet must sit at 0.3-0.5 mm new and must be re-shimmed before it exceeds 0.8 mm, or the brake will not release reliably and the motor will burn out trying to lift against a partially-engaged brake.
- Wire Rope Drum or Chain Pocket Wheel: On wire rope hoists, a grooved steel drum guides the rope into a single layer with a fleet angle below 4° at the rope sheave. On chain hoists, a 5-pocket or 4-pocket wheel engages each chain link in turn, and the link pitch must match the pocket pitch within ±0.1 mm or the chain will climb the wheel under load.
- Limit Switches: Geared rotary limit switches stop the motor at the upper and lower travel limits, with a typical accuracy of ±5 mm at the hook. A secondary emergency limit (often a weighted lever) provides a redundant cut-off if the primary switch fails — required by most lifting standards including ASME B30.16.
- Load Hook with Safety Latch: A forged alloy steel hook with a spring-loaded safety latch prevents the sling from jumping out of the throat. The hook is rated to deform visibly before failure (DIN 15401), so any measurable throat opening — typically a 10% increase from new — means the hook has been overloaded and must be replaced.
- Control Pendant or Radio Remote: A 24-48V low-voltage pendant with up/down/stop buttons keeps the operator out of the path of the load. Two-speed pendants use a two-stage button — first detent gives creep speed, full press gives main speed — which is how you spot a 2-tonne motor block onto a mounting plate without overshooting.
Industries That Rely on the Electric Hoist
Electric Hoists turn up wherever a load is too heavy or too repetitive for a manual chain block. The choice between wire rope and chain comes down to lift height, capacity, and headroom — chain hoists win for compact installations up to about 5 tonnes, wire rope hoists take over above that and for fast lifting at long heights. Duty cycle matters more than capacity in service life, so a hoist rated FEM 1Bm in a high-cycle assembly line will burn through brake linings in under a year, while the same hoist on a maintenance crane in a water-treatment plant lasts 15+ years.
- Manufacturing: Demag DC-Pro chain hoists on monorails moving stamping dies in automotive press shops
- Entertainment Rigging: CM Lodestar 1-tonne chain hoists flying lighting trusses at concert venues, controlled by a Motion Labs distro
- Warehouse and Logistics: Konecranes CXT wire rope hoists on overhead bridge cranes loading steel coils onto flatbed trucks
- Wind Energy Service: Liftket chain hoists permanently mounted inside wind turbine nacelles for gearbox component changeouts
- Shipyards and Marine: Stahl SH wire rope hoists on shipyard gantry cranes positioning hull plates for welding
- Construction: Harrington NER electric chain hoists lifting HVAC rooftop units up 8-storey commercial buildings
- Foundries and Steel Mills: Heat-resistant Yale CPV hoists handling ladles and ingots in continuous casting bays
The Formula Behind the Electric Hoist
The core sizing equation for an Electric Hoist is the motor power required to lift a given load at a given speed, accounting for mechanical efficiency. At the low end of the typical lift-speed range (4 m/min creep), motor power requirements are modest and you can run a tightly-rated motor at 100% duty. At the nominal lift speed for industrial hoists (8 m/min), you size the motor with about 15-20% headroom for inrush and brake-release transients. At the high end (16 m/min two-fall reeving on light loads), inertia of the drum and rope itself starts to dominate the starting torque, and undersizing the motor here causes nuisance overload trips on every lift start.
Variables
| Symbol | Meaning | Unit (SI) | Unit (Imperial) |
|---|---|---|---|
| Pmotor | Required electrical motor power | kW | hp |
| m | Lifted load mass | kg | lb |
| g | Gravitational acceleration (9.81) | m/s² | ft/s² |
| vlift | Hook lift speed | m/s | ft/min |
| ηtotal | Combined gearbox + drum + reeving efficiency (typically 0.78-0.88) | — | — |
Worked Example: Electric Hoist in a brewery cellar tank-lifting hoist
A craft brewery is specifying an Electric Hoist on a jib crane to lift 1,500 kg fermentation tank lids and dip-tubes onto 3,000 L unitanks. The cellar ceiling is 4.5 m, lift height is 3.2 m, and operators want to spot the lid onto the gasket without crushing it. You need to size the motor power for nominal lift speed and confirm the operating range from creep speed up to fast lift on empty hook returns.
Given
- m = 1500 kg
- g = 9.81 m/s²
- vlift,nom = 0.133 (8 m/min) m/s
- ηtotal = 0.85 —
Solution
Step 1 — at the nominal industrial lift speed of 8 m/min (0.133 m/s), compute required motor power for the loaded lift:
That sets the floor for motor selection. You would specify a 3.0 kW two-speed hoist motor (next standard size up), which gives roughly 30% headroom for brake-release inrush and starting torque.
Step 2 — at the low end of the operating range, creep speed of 2 m/min (0.033 m/s) for spotting the lid onto the gasket:
Creep speed is what makes this hoist actually usable — at 2 m/min the operator can drop the lid onto a 3 mm-thick silicone gasket and feel it touch without compressing. A single-speed hoist running 8 m/min will mash the gasket flat every time, and you will replace gaskets every month instead of every year.
Step 3 — at the high end, empty-hook return at 16 m/min (0.267 m/s) carrying just the 80 kg block weight:
Steady-state power is trivial at empty-hook return, but the inrush to accelerate the drum and 30 m of rope to full speed in 0.3 seconds peaks at roughly 4-5 kW for a fraction of a second. This is why two-speed pole-changing motors are standard for lifting duty — the motor handles the loaded slow speed comfortably while still accelerating the empty hook quickly without nuisance-tripping the overload relay.
Result
The brewery needs a 3. 0 kW two-speed Electric Hoist with a rated capacity of at least 2,000 kg (giving 33% margin over the 1,500 kg working load) — a Stahl ST 20 or Demag DC-Pro 2-500 in 2/1 reeving fits the spec. At 8 m/min nominal lift the lid clears the tank in 24 seconds, fast enough to keep production moving but slow enough to keep operators relaxed. The 2 m/min creep gives the gasket-friendly soft-set, and the 16 m/min empty return cuts cycle time roughly in half on the unloaded leg. If you measure the loaded lift drawing significantly more than 2.3 kW at the panel, suspect (1) a partially-dragging brake that has not fully released — check brake gap and coil voltage at the brake terminals, (2) low η<sub>total</sub> from a dry gearbox running on degraded oil where viscosity has climbed above ISO VG 320, or (3) excessive fleet angle on the rope above 4° causing the rope to climb the drum flange and add friction.
Choosing the Electric Hoist: Pros and Cons
Choosing an Electric Hoist over the alternatives comes down to duty cycle, lift height, and how precisely you need to position the load. A manual chain block is cheap and needs no power, but a human on the chain caps practical lifts at maybe 1 tonne and 6 m. A pneumatic hoist matches an electric for explosion-proof environments but burns shop air at brutal rates. Here is how they compare on the dimensions that actually drive the buying decision.
| Property | Electric Hoist | Manual Chain Block | Pneumatic Hoist |
|---|---|---|---|
| Typical capacity range | 250 kg to 50 t | 250 kg to 5 t | 250 kg to 100 t |
| Lift speed (m/min, full load) | 4-16, two-speed | 0.5-2 (operator-limited) | 6-30, infinitely variable |
| Positioning accuracy at hook | ±5-10 mm with creep speed | ±2 mm (operator skill) | ±2-5 mm (variable speed) |
| Duty cycle (FEM class) | 1Bm to 4m, up to 60% ED | Unlimited cold, limited by operator | 100% ED, continuous |
| Capital cost (1-tonne unit) | $1,500 - $4,000 | $300 - $700 | $3,500 - $8,000 |
| Operating cost | Low (electric, ~2 kWh/cycle) | Operator labour only | High (compressed air, ~5x electric) |
| Hazardous-area suitability | Requires expensive ATEX variant | Inherently safe | Inherently safe (no sparks) |
| Service life (hours under FEM 2m) | 10,000+ h with maintenance | 20+ years light use | 8,000-15,000 h |
Frequently Asked Questions About Electric Hoist
Nine times out of ten this is a brake that is not releasing fully. A spring-applied brake with low coil voltage, a corroded armature face, or an air gap that has worn beyond 0.8 mm will drag against the rotor, and the load cell or motor current sensor reads that drag torque as additional load. Measure brake coil voltage with the up button pressed — it should be within 5% of nameplate. Also check the gap with feeler gauges; anything over 0.8 mm needs re-shimming.
The other common cause is a load cell that drifted out of calibration during shipping. Most hoist controllers have a tare procedure — run it with the empty hook block hanging and recheck.
Two-fall reeving (rope passes through a sheave on the hook block and back to a dead-end) halves the rope tension and halves the lift speed at the same drum speed. You pick two-fall when you need higher capacity from a smaller motor and gearbox, or when you need a true vertical lift with no hook drift sideways as the rope unspools — which matters for precise machine assembly work.
Single-fall is faster, simpler, and cheaper, but the hook drifts laterally as the rope wraps across the drum width. For loads above roughly 3 tonnes or any application where the hook must stay vertical (CNC machine loading, mould handling), specify two-fall.
This is almost always the lowering control trying to use the motor as a brake against the falling load. On a single-speed hoist with an old contactor controller, the motor pulses against the load and you feel it as juddering. The fix is either a VFD-controlled hoist or a proper load brake (Weston-style mechanical brake) inside the gearbox that converts overhauling-load energy to friction heat.
If your hoist already has a VFD and it still judders, check the deceleration ramp setting — too short a ramp causes the drive to trip in and out of regen current limit. Stretching the deceleration ramp from 0.5 s to 1.5 s usually cures it.
No, and this is one of the most common ways hoists get destroyed. The drum guides, fleet angle limits, and rope groove geometry all assume the rope leaves the drum within ±4° of vertical. Pulling horizontally puts the rope at an extreme fleet angle, the rope climbs the drum flange, and you crush wires within a few cycles. The brake is also sized for vertical loads only — a horizontal pull can stall the motor without the brake providing any useful resistance.
For horizontal pulling use a winch designed for the job (Warn, Ramsey, Tulsa). Winches have level-wind systems and brakes rated for the side-loaded application.
5 lifts per shift on an 8-hour shift is roughly 0.6 lifts per hour. Even at 30 seconds per lift cycle that is well under 10% running time, which puts you firmly in FEM 1Am or 1Bm territory. Specifying anything higher is wasted money — a 2m hoist costs roughly 30% more than a 1Bm with the same capacity.
The exception: if any of those 5 lifts hits 100% of rated capacity, bump the class up one notch. FEM duty classification is a function of both running time and load spectrum, and a hoist that always lifts at full rating wears faster than one that mostly lifts partial loads.
Three likely causes. First, line voltage sag — induction motors are speed-sensitive to voltage, and a 10% voltage drop at the motor terminals (common on long supply runs without proper cable sizing) gives roughly the speed reduction you are seeing. Measure voltage at the motor under load, not at the panel.
Second, frequency drift on a generator-fed site. Hoists are designed for 50 Hz or 60 Hz; a generator running 47 Hz delivers proportionally slower lift. Third, on two-fall reeved hoists, check that the rope isn't slipping at the dead-end socket — a loose wedge socket lets rope creep, which the operator perceives as slow lift even though drum speed is correct.
Brutally critical. Wire rope fatigue life scales roughly with the cube of the D/d ratio. Drop from 22.4:1 (FEM 2m minimum) to 18:1 and rope life falls to about half. Drop to 14:1 and you are looking at one-quarter the cycles before broken-wire discard criteria are met.
This is why retrofitting a bigger rope onto an existing drum to 'make it stronger' is a disaster — the smaller D/d ratio kills the rope faster than the extra rope strength helps. If you need more capacity, add a fall (go from 1-fall to 2-fall) rather than upsizing rope on the same drum.
References & Further Reading
- Wikipedia contributors. Hoist (device). Wikipedia
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