When selecting a gate motor for the entrance gate(s) to a medium to large townhouse complex or housing estate, it goes without saying that the operator is going to work hard and that it pays in the long run to spend a bit extra to get the right product.
1. Overheating. When all the residents stream out of the property in the morning, the gate motor is going to operate almost continuously, opening and closing for each vehicle leaving. With some operators the power supply cannot cope and with other products the motor overheats.
2. Wear and tear on the operator due to usage. A complex with 30 houses where each house has two vehicles: if we consider that one of the vehicles of each residence will operate the gate at least four to six times a day and the second vehicle at least twice a day, add to this visitors and other maintenance vehicles, etc, it is not unfeasible for the entrance gate to operate conservatively in excess of 250 times per day. This equates to no less than 90 000 operations a year.
This number will increase in direct proportion to the number of houses. In a complex with 60 houses, a motor will be operating approximately 900 000 times over a five-year period. Even if this size complex has an entrance and an exit gate in order to share the load, this is considerable usage for any operator.
3. Is the gate motor strong enough to do the job? Besides the fact that gates designed for these commercial/industrial installations are typically fairly large and require a fair effort to move, they are generally poorly maintained. With all the usage referred to above besides the wear and tear of the operator the gate itself will also degrade. What started initially as a smooth sliding gate soon wears to an installation where the wheels are worn, the rail is damaged, the gate does not align with its catch brackets, etc. Without preventative maintenance all these factors put extra strain on the gate motor.
When selecting a gate motor that is going to operate in high usage applications what are the key components to look out for?
Duty cycle
An operator capable of ongoing start and stop operations. Check the duty cycle rating of the operator and ensure that it will comfortably cope with requirements of the applications referred to above.
Reliability
It is preferable to use an induction motor that has minimal components that will wear, these being typically only the bearings that support the rotor of the motor. A motor fitted with good quality bearings can do well in excess of a million operations without requiring replacement.
Wherever possible avoid systems that use mechanical limit switches. These are external devices that interface with a striker mounted on the gate. Being external devices, the limit switches are fairly exposed to the elements and also susceptible to wear.
The majority of sliding gate motors will have some form of gearbox and it is critical to ensure that the gearbox gear-set is properly lubricated. In high volume applications it is preferable to use an oil-bath that not only helps to cool the gearset but also ensures continuous lubrication of the contact points of the gears.
Operator strength
In addition to the overall operator being well designed, preferably having a gate carrying mass well exceeding that required for the installation, the motor must be able to deliver adequate starting and running torques. A sliding gate being an inertial load requires a major effort to get the gate sliding. When the sliding condition of the gate degrades with usage, extra effort will be required to get the gate moving and keep it moving.
For more information contact Richard Rohnan, Centurion Systems, 011 699 2402, [email protected], www.centsys.co.za
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