A garage door opener is usually a motorized automatic device that manually opens and closes garage gates automatically controlled by switches on the garage gate. Garage doors are controlled by push buttons and other switches mounted on the garage wall, so it is usually not necessary to use a garage door opener if you have an automatic garage gate installed. However, many garages still contain a manual opener, and if your gate is remote controlled, you may find it useful to have a remote garage door opener for easy opening and closing of your garage gates. Garage door openers that use electricity or batteries are usually very loud, but some models are silent, making them suitable for use in residential areas.
There are two main types of garage door opener mechanisms – the belt drive and the trolley type. The belt drive system uses pulleys on a long steel belt. The chain is similar to the cable that runs up and down the stairs, passing the pulley on each side of the garage, and is able to pull the belt to use tension. The chain and belt are slowed by a counterweight at the bottom of the trolley, so that the gate closer pulls the trolley to a halt, allowing the chain and belt to run parallel to each other. The noisy chain may be unpleasant when operated, and most of the models require a motor to operate.
The trolley system involves two parallel chains, each connected to a terminal. Each terminal has a sensing device mounted on a metal rack. When the vehicle approaches the garage door opener, the sensors send signals to the trolley, which then activates the pulleys and the chain pulls the gate to close. Garage gate closer units are available in several standard voltage and frequency ranges, and many are suitable for use with automatic gates that are sensitive to low or high frequency signals. These units manufactured by relay systems are very popular in residential garages because they are easy to install, easy to operate, and provide high levels of reliability. Most of these units manufactured by relay systems have a minimum of three separate channels, making them ideal for automatic gates that need to sense an open, closed or neutral zone.
Relay systems are powered by one of three different power sources: AC, DC, or batteries. AC direct transfer is the most reliable form of operation and allows the garage door opener motor to run both when the vehicle is in operation and while the trolley is parked. Most systems provide the ability to switch the batteries, if required, but this is not generally necessary. The batteries can also suffer from low capacity, so it is necessary to regularly check their state of charge.
Belt drive openers are designed to be more reliable and powerful than the screw operated garage doors. This means that these types of openers can run even when the trolley is not in use, and they can work in even colder climates. They are also more expensive than trolley operated types. Belt drives require a special type of power cable that is much shorter, and requires no electrical connection.
The final type of garage door opener motor is geared to work in conjunction with the trolley system, and is basically a reversing chain driven by a trolley. These systems are very reliable and allow for the easy lift and lowering of the garage doors. However, they tend to use more electricity than any other system.