What it actually decides.
A chain motor, or electric chain hoist, raises and lowers a load on a link chain running through a motorised gearbox. In event work the common capacities are a quarter, a half, one and two tons, and the ones on a typical corporate or concert job are the half and the one.
Capacity is the obvious specification and it is rarely the binding one. A motor is attached to something above it, and the structure, the sling and the shackle in that chain of parts all have their own limits; the system is rated at the weakest of them, not at the hoist. Lifting at or near a hoist’s rated capacity also requires the anchorage and the rigging above it to be rated higher, because starting and stopping a load adds force that a static calculation does not show.
The question that gets skipped is what happens when the load stays up. A standard hoist is designed to lift, and the usual expectation is that once it is parked the load is carried by secondary rigging rather than by the motor and its brake. Hoist classifications exist for leaving a load on the motor alone, and for moving a load while people are underneath, with double brakes and additional monitoring — these are European designations rather than United States law, and productions and venues specify them by contract.
Hoists are inspected before use and load tested periodically. A rental motor should arrive with that history behind it.
We own this equipment.
Staging and rigging — owned inventory, our own crew, and a site survey before anything is specified.