Garage door openers are operated by a motor, either electric or battery driven. An automatic garage door opener operates by sensing movements near the opener and opening the garage door. Garage doors are generally controlled by electrical contacts installed in overhead tracks. Garage doors that use an extension system have track sections with adjustable brackets, tensioned springs, and a drum or roller assembly at the center. Garage doors that are operated electronically open with a transmitter mounted on a drum, which senses the movements around it and starts for the door.
The garage door opener motor is mounted on a trolley that can be raised or lowered by a remote control. Most garage door openers have a clutch system that allows the motor to move smoothly without stopping. Some units have a safety mechanism that allows only the forward stroke of the trolley to raise or lower the garage door. This prevents the motor from being accidentally drawn up or down by someone standing near the garage door. Most have an emergency release control that allows the motor to shut off if the circuit breaker is tripped.
In addition to having an automatic function, some have speed adjustments to allow you to change speeds. There are also separate speed controls for opening and closing. A trolley drive belt is usually made of rubber or synthetic material, and the speed adjustment is usually controlled by turning a screw in the belt. The chain drives the belt, which is also made of rubber or other material.
There are several different styles of garage door opener drive belts. belt drives tend to be quieter than chain drives. Belt drive openers do not require the use of chains and are sometimes called belt-drive openers or just belt openers. Belt drive openers generally have a larger motor capacity and are heavier and more bulky than chain drive openers.
Garage door openers are equipped with motor controls that allow the operator to select from several different operating modes. The most popular mode is the self-retracting mode. The motor does all of the work to lift and lower the door, and then it must be manually turned back on again. Other types of motorization include continuous motor, which moves the motor along a fixed path inside the house; positive displacement or PDS, which uses a clutch system to increase the effectiveness of any one motor; and variable-speed motor, which adjusts the speed of the motor as the garage doors move up and down. The various modes available control the speed and amount of energy used by the motor.
Speed adjustments will make the garage door opener run more quietly, especially when you have small children or pets around the house. Some newer door openers have a “quiet” mode, which means they operate at a lower speed. You can also buy garage door opener parts, such as motor drives, that are designed to run on solar power, which will help to save you money on your electric bill.