A gate motor (sometimes 'gate operator' or 'actuator') turns a manual gate into an automatic one. Sliding gates use rack-and-pinion drive units mounted to a pad next to the runout. Swing gates use either ram-style actuators (one per leaf, mounted between post and gate) or underground motors fitted in a sealed box below the hinge.
The big-three brands in Australia are CAME, Beninca, and FAAC, with Centsys, Nice, and Centurion also widespread. Sizing depends on gate weight and duty cycle. A residential single sliding gate up to 400 kg runs on a CAME BX704 or equivalent. Heavy commercial gates 1000 kg-plus need industrial duty drives like a CAME BY3500.
Every motor needs safety devices on the safety circuit (photo eyes, safety edges) plus a manual release for power failures. Australian Standard AS/NZS 4505 covers the safety requirements for automated gates.