Automatic gates form an important part of perimeter security. Consequently, the emphasis in the design of gate automation products, particularly in this country, focuses more on security than convenience. This is important to stress as many systems are based on European and American designs where the convenience rather than security is the overriding factor.
Such (imported) systems may not allow for important provisions such as mains power failure back up which, in the South African context, is necessary given the nature of local criminal modus operandi, electrical storms and electrical grid downtime which are not uncommon in many parts of South Africa.
Speed and mode of operation
An inherent potential security problem occurs when the gate is open or in operation, as it then creates the biggest hole in a perimeter security system. Both the speed and mode of operation of the automatic gate becomes important. It is not uncommon for criminals to use the opportunity before the gate closes to enter the premises. What is required is a fast moving gate, which closes the moment a vehicle has passed through the entrance.
A critical requirement of any access automation system is safety. Unfortunately, using safety beams, inductive loops and anti-crushing mechanisms built into the motor to make the system safe, can aid any would-be intruder to override the system when in operation. For instance, if the vehicle has passed through the entrance, by blocking the beam or physically obstructing the gate before it starts to close, will, as designed for safety purposes, prevent the gate from closing and expose the entrance to infiltration. It becomes a Catch 22 situation and therefore when designing the access automation system, safety factors vs security requirements must be carefully balanced.
Selecting gate motors
In the same way that it is important to select the correct tool for a job, so too must the correct gate motor be chosen during automation of a gate. Too often price dictates a purchase. This is certainly the case when gate operators are installed in commercial and industrial applications. It is easy to under-estimate how hard a gate motor in a commercial or industrial installation might have to operate, where:
* The frequency of operation is typically very high, resulting in problems such as over-heating and excessive wear and tear.
* The average industrial gate is large and of heavy construction and difficult to move.
* Gates in these applications are often abused. Besides vehicles knocking into the gate, the running conditions deteriorate leading to undue stress being placed on the automation. Preventative maintenance is often neglected in the gate automation industry.
Reliable installation crucial
How is a reliable installation guaranteed when automating an existing sliding gate installation? The first thing is to make sure that the mechanical gate is correctly installed.
* The gate must have suitable mechanical end stops, which can withstand the full momentum of the gate particularly when driven under full power of the motor.
* The gate should be properly balanced. Not only must it be perfectly balanced vertically, by the top guide rollers, but it must also be balanced horizontally so that it slides open or closed with equal force.
* Due care must be taken to ensure that the gate slides as smoothly and lightly as possible. The solution to the problem of a badly running gate is not by installing a stronger motor. Remember also, that in the event of a system failure or emergency situation, an average person must be able to slide the gate open with relative ease.
There are also three factors to consider when measuring up a sliding gate in order to select the correct operator:
1. The physical mass of the gate. Depending on the speed of the operator this yields a measure of the momentum in the system and determines the strength and size of the operator gearbox.
2. The pull force required to move the gate. This is a measure of the rolling friction in the system and determines the power of the operator motor required.
3. The duty cycle of the installation. In an industrial application it is critical to know how often the system is required to operate. Besides the accelerated wear and tear, many systems are susceptible to overheating and consequential thermal shutdown in multiple usage applications.
Make sure that the specifications of the sliding gate operator under consideration fall within these parameters. Secondly, bear in mind the downtime cost implication if a product of inferior quality fails. A good quality product might cost more up front, but it is a better long-term investment. 'You get what you pay for!'
Source: Centurion Systems
Making gate automation work
Gate automation is not simply a 'plug-and-play' process, but neither should it be a 'plug-and-pray' one. In most instances, gate automation solutions need to be custom fitted to the entrance gate taking into account the availability of electrical supply and the size and operating characteristics of the gate. It is important to carefully select a reliable and reputable company to install the unit. All too often price is the determining factor, without having taken the following points into consideration:
* Scrutinise the company's credentials and then take the time to contact a few of their references.
* Make sure that these customers were happy with the quality of their installation.
* How efficiently did the installation company respond to a service call if it arose? Unlike a faulty TV or household appliance, the gate motor is a fixture and not easy to remove for servicing. At the same time the gate operator interacts with the gate itself and it is better that a suitably qualified technician checks out the operation of the two components together.
* Did the installation adhere to necessary electrical regulations?
* Was any consideration paid to lightning protection, particularly if one lives in a bad lightning region?
* Try contacting the manufacturer of the specific motor you have chosen and ask their advice.
It goes without saying that when deciding on what gate automation to fit, besides choosing a quality product that satisfies all your performance requirements, unless you have made sure that it is properly installed you cannot be guaranteed of a reliable system. But we will say it again anyway. Buyer beware!
Source: Centurion Systems
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