What type of gate motor do I need?

Sliding gate motors
If you already have a sliding gate then this is the motor type you will need. If you do not have a gate yet and are considering which gate and motor combination will work best for your property here are a few points to note about sliding gates:-

Smaller operating area - the sliding gate needs space to move equivalent to twice the width of the gate opening, but as the gate does not swing you will have move available space on the property's driveway/parking area.

Hardware - you will need guide track and wheels, support rollers/brackets and gate stops or a cantilever systems to support the gate and ensure it runs true.

Drive mechanism - you will need to decide whether you wish to use a cog and rack drive or chain drive. Cog and rack motors are quieter but require a truer gate travel, whereas chain drives are noisier but more forgiving if the gate has a bit of a wobble!

Security - sliding gates are more difficult to ram or force open, so where anti-vehicle protection is required a sliding gate is recommended.

Swing gate motors
They can generally be used in either double of single gate configurations. There are six types of swing gate motor, each with strengths and weaknesses that may or may not meet your criteria.

Ram, standard
Cost effective - these are the vanilla of gate motors, with the motor configured perpendicular to the ram, making them a simple but effective design and usually cheaper than other types. Look for quality materials and longer warranties. Usually only inward opening with an angle of 90° to 130°. Often unsuited for gates with large pillars.

Ram, Linear
Slim-line - these motor have improved aesthetics with the motor configured in-line with the ram to create a slimmer / more compact design. They tend to be cost effective, but will be more expensive than standard rams due to the more involved engineering. Usually only inward opening with an angle of 90° to 130°. Often unsuited for gates with large pillars.

Tow-Eye, Linear
Covered mechanism - tow-eyed gate motors are designed so that there is no exposed ram when the gate is actuated. They therefore offer slight improvements in motor lifetime as the systems offer better weather protection. Tow-eye gate motors also have improved aesthetics, offering a less-mechanical and more discrete appearance when opening and closing the gate. They will generally be more expensive than like for like linear rams. Usually only inward opening with an angle of 90° to 130°. Often unsuited for gates with large pillars.

Wheeled
Small pillars and restricted spaces - these motors are recommended where either gatepost/pillars are too small to mount rams or where the space behind the gate is limited (e.g. the gate is flush to a driveway wall when open). Wheeled motors are also recommended when underground motors are impractical (high water tables / poor drainage). These generally require a metalled/paved drive and unsuitable for shingle/gravels drives, however there are agricultural models designed for uneven ground (farm tracks). Usually only inward opening, the maximum angle being determined by the hinge position (i.e. these motors are not limited by geometry but will open as wide as your gate aspect and hinge will allow).

Articulated
Large pillars or outward opening - theses gate motors have a two-part arm which bends (articulates) allowing them to reach around large pillars and gateposts when required. Generally these motors can also be re-polarised allowing them to open a gate outwards (assuming the driveway approach is your own property and does not encroach on anyone else's land or public land). Usually opening with an angle of 90° to 130°.

Underground
Discrete - ideal for gates where aesthetic sensibilities are paramount and the automation is hidden as much as possible. Suitable for most types of drive and usually available with either galvanised chambers / foundation boxes or stainless steel versions these motors are usually welded to a shoe on the underside of the gate. Drainage and a soak-away are necessary even on sealed units and oil-bath motors as these systems are not designed to remain immersed, standing in water. Generally underground motors will be inward opening with maximum angle of 90° to 130°; however most have adaptor kits allowing them to open either 180° or 360°. Some underground motors can be paired using an adapter bracket to actuate a single leaf, allowing bigger gates to be moved.