Electric Gate Systems – Underground Gate Automation
In an earlier post, a few days ago, I briefly set out the various methods of automating swing gates. One such method is to install an underground gate automation system.
As you can probably guess from it's name - the underground gate automation system is installed in the ground - directly below the gates. In fact, the motor becomes the bottom hinge of the gate - as well as the means of opening and closing it.
If there is only one gate leaf, there will only be one underground motor. If the gates are a pair of leaves - then there will be two motors - one for each gate.
Underground gate automation is a very popular option for the automation of wrought iron gates - as none of the equipment is visible. They are also suitable for automating wooden gates also - but wind loading must also be considered when using them on wooden gates (we'll address this in a separate post).
Underground gate automation comes in a few different variants. And there are reasons for this. The most popular is the 230v AC motor and they come in different load capacities (the weight of gate and leaf length) from 250kgs to 900kgs and leaf lengths up to 4m long. These are suitable for domestic driveways and light commercial usage - where the number of cycles per hour is low (the gate won't be opened very often each hour)...
Types of Underground Gate Automation
For gates that are being opened frequently - there are 24v DC variations, and also hydraulically powered underground gate automation systems - which are designed for operating more or less continuously (maybe for a carpark or busy commercial premises). The hydraulic operators can also have higher load capacities for gates over 1000kgs. However, we have a very large hydraulically powered underground gate automation system for gates that can weigh up to several tonnes (for large commercial premises and industrial use), where security is important, or risk of vandalism is a concern. This heavy duty system will be addressed separately in the next post - as I consider it a different animal!
For most driveways, the 230v AC system will be the popular choice. It's neat and tidy, and when installed properly, it's very reliable. I say that because, of all gate automation, it has the poorest reputation in terms of reliability - and generally that's not the fault of the equipment. I'm hesitant to blame the installer - but in many cases - he or she is to blame.... Underground gate automation systems - because they are in the ground - must be installed with soak-away drainage - to let the water out of the foundation casings (that's the steel box that is concreted into the ground - that the actual motor in bolted into).
The motors are suitable for operating in water for a short time - maybe up to a few days at a time - as long as the water does drain away. Prolonged immersion is a different kettle of fish! Eventually, the motor seals will perish in the water and it makes it's way into the motor. We all know that water and electricity DO NOT MIX! Failure in this way is very likely to be permanent. The water causes the windings in the motor to short out (blowing fuses) and also corrosion of the motor internals. An new motor will be required in this case.
If drains were installed, to let the water out - they need to be kept clear. That means that if you have your driveway power washed, or if you've had building works done - there's a good chance that either the power washing has washed the dirt of the drive down into the motors. Sand from building works also ends up in the motors - as the rain washes it down the drive and into the motors. In either case, the drains become blocked. The recommendation is always to have an underground system maintained at least once a year - but after installation, most people will not look for maintenance until something goes wrong. so if you're getting building works done, or power washing - it's highly recommended that you don't wait too long before having the gate automation serviced. Part of this will be to remove the motors and clean out the foundation casings, and re-lube the seals on the motors.
Quick note - We always install the soak away drains, when fitting underground gate automation - whether to new of existing gates. Unfortunately - we're in the minority!
The last piece I have for you on this - is to answer a question that comes up with nearly every customer - "What happens when the electricity is off". That's easy. We provide you with special keys to "manually" release the gates - so that you can swing them open by hand. The manual release can be operated from inside or outside the gate. I always tell customers to keep the keys for this in the boot of their car - so that they will always have them with them.
I hope this answers a few quetions that you may have of the subject. If not, please feel free to contact me. Adrian
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