Sizing a Slide Gate Operator
Operators are rated on three numbers and most people compare only one of them. The selection table at Mount Pleasant Sliding Gates Narcoculture keeps weight, length and duty cycle apart, because sliding leaves in Mount Pleasant regularly sit inside a weight rating and outside the length rating on the same unit.
Weight Is the Obvious One
Every operator quotes a maximum leaf weight. Establish the real figure from the fabricator cut list rather than estimating, and remember that a cantilever leaf includes its counterbalance tail, so it is considerably heavier than the visible opening suggests.
Length Is the One That Is Missed
Length rating exists because a long leaf has more inertia and more friction along its guides, and because the drive has to control it at both ends of travel. A gate under the weight limit but over the length limit will run perfectly on the day it is commissioned and will wear the drive train fast. Both limits have to be satisfied.
Duty Cycle
Residential units are built for a handful of cycles an hour. A shared entrance, a short term rental, or a household with several vehicles can multiply that easily. Exceeding a duty cycle does not cause an immediate fault, it causes heat, and heat is what shortens motor and board life. Where usage is high, a continuous duty unit is the honest specification.
Wind Is a Fourth Input
On an exposed coastal lot a solid or louvred infill adds a substantial intermittent load. That does not appear in any rating table, so the practical approach is to size up a class when the gate is not open picket, rather than to run a marginal unit at a raised force setting.
Power and Backup
Confirm what supply is available at the post before choosing. A low voltage unit with a battery backup and a solar panel suits a run where trenching a mains supply is expensive, and it also rides out an outage. A mains powered unit gives more force and faster travel and stops entirely when the power does, unless a backup is fitted.
Do Not Size From the Old Unit
Replacing like for like repeats whatever mistake was made the first time. If the previous operator was running at a high force setting or failed early, that is evidence it was undersized rather than a specification to copy.