September 28, 2018

How an Electric Garage Door Opener Works

Electric garage door opener - LiftMaster

You use your garage door opener every day of your life – have you ever thought about how it works? As one of the most useful little gadgets we have, the garage door opener is often taken for granted. Next time you use your opener to head to work, or to come home after a long day, you may want to stop and think about what goes into this handy device.

Here are some fundamentals that will have you looking at your door opener differently the next time you go to use it, and hopefully give it just a little more care.

Different Types of Garage Door Openers

Most garages in North America are opened by a central garage door opener, which means that the door is opened by a system that involves a trolley, driven by a motor, which is installed on the ceiling right at the center point of the door.

However, if you have a garage that has a unique ceiling, like a cathedral ceiling, you may need a garage door opener that is bolted to the wall next to the door. This is called a Jackshaft opener.

How the Remote Control Works

The garage door opener and the remote controller that you have communicate with each through radio transmission. (The controller is the remote, and the opener is the receiver.) The remote sends a radio wave on a precise frequency, 315, 315 or 390 MHz, which is picked up by the receiver in the motor housing. This radio signal causes the door to open or close.

If you press your remote and the door doesn’t open, the problem may be that the remote isn’t working – or it may be that the opener itself isn’t picking up the signal. There are a few common causes for this problem. Dead batteries, power outages, and other issues could be causing the two devices to not communicate.

Can People Pirate Garage Door Signals?

Have you ever heard someone say that a plane passing over their house can open their garage door? That’s a myth! Radio frequencies used by air planes are not on the same wavelength as those used by your garage door opener.

However, it is true that garage door openers manufactured before 1993, could possibly be “pirated” by criminals who understand how radio frequencies work. The chances of this are very slim, but it is possible because these devices were made using a technology based on DIP switches (put in +, 0 or – positions). Although these remote controls have up to 8 positioning clips (in addition to +, 0, -), it can happen that a malicious person can pick up the signal and can open the garage door in your absence.

Since 1993, the company Chamberlain, which includes the LiftMaster and Craftsman brands, has used their SECURITY+ system that allows up to 1 billion possible codes. What’s more, each time a code is used, it is changed, so it is never the same code the next time around.

Then again, in 2013, Chamberlain changed garage security once more with the introduction of their MyQ system that allows you to open and close your garage door from your mobile phone, tablet or laptop.

Finally, in August 2017, Chamberlain added a Wi‑Fi feature to some of its door openers. As you can see, it is becoming increasingly difficult to copy the open/close signal for your garage door opener.

MyQ Smartphone

Different Types of Drives

Garage door openers use drives to control the garage door. There are a few different kinds, like the chain drive that mimics the way a bicycle chain works. Another common drive type is a rubber belt reinforced with steel, like that used for making car tires. This latter type of opener is much quieter than the chain drive. There are also screw drives, but these are not commonly used.

How Strong Is Your Motor?

Most garage door openers have a motor that is an AC‑type (alternating current), which offers either ½ or ¾ HP. However, it’s not uncommon to have a DC type. One feature of DC motors is that their speed varies. They start slowly, increase to regular speed, then slow before stopping.

The strength of an AC motor cannot be compared to a DC motor. For an AC motor, strength is calculated in horsepower (HP) while DC motors are rated in newtons.

Keep in mind that door openers are meant to lift a weight of up to 225 lb. (100 kg.). That means that it can also push down with that same amount of strength. This is why your garage door simply must be well balanced. To be safe, the door is balanced by a spring and counterweight system. This means that even though the motor can push down with a lot of force, the door will only weigh about 8 to 10 lb. (4 to 5 kg) itself. At that weight, opening your door with just one hand is easy.

A Properly Working Reversal System

Since 1993, every single garage door in America has two automatic reversal systems. This is due to laws to help prevent accidents and injuries. The two types of reversal systems are mechanical and photo eyes.

  • Photo eyes: Two small units, one on each side of the door, are placed between 4 to 6 inches (10 to 15 cm) from the floor. For a closing garage door, if the invisible beam of light between the two units is broken, the door must immediately reverse direction.
  • Mechanical: when the door is lowering, if the opener senses resistance, such as hitting an object or person, it must stop automatically and reverse direction.

Get in Touch with Us to Learn More

We invite you to check out our showroom or our online Design Centre, to assist you in selecting the style that fits you best. You can also view a lot of great examples of new styles in our image gallery.

Contact us to learn more about garage door operation, toll free at 1-800-409-3667. We are the garage door professionals, and can help you learn about the various elements, find options that suit your budget, and more. If you’d like, we can email you a quotation.

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