If you rent light towers for your operations, or if you don’t do much nighttime work, it’s easy to think of them as “set-it-and-forget-it” units. If they use diesel engine power, however, light towers need many of the same maintenance considerations as other mobile equipment and should be managed as such.
Essentially, light towers are diesel-driven generators combined with a lighting element, which has maintenance requirements of its own.
“When operated properly, light towers are a mature enough product that they shouldn’t require more than regular engine service and routine inspections in most cases,” says Gary Burman, customer service and warranty representative for Allmand Bros. “However, it’s important to always read the engine service and operator’s manual as well as any warning labels on the machine before operating a light tower.”
Jim Siffring, product manager for generators at Atlas Copco Construction Equipment, reminds managers that diesel-powered light towers operate just like any other diesel engine found in generators and air compressors, so they require the same type of maintenance.
“Users need to remember to periodically change the oil and filters, maintain all fluid levels and clean the lenses,” Siffring says. “Contractors also should look for light towers with features that promote long life and easier maintenance. For instance, some Atlas Copco light towers have an automatic engine shutdown system that stops the engine if the oil pressure becomes too low or the coolant temperature is too high. This protects the engine from damage.”
As with other mobile equipment, if light towers incorporate ease-of-maintenance features, field maintenance is more likely to get done. Features like side panels and flip-open top panels for easy access to the engine and components are a maintenance manager’s friend.
“In most cases, users will be dealing with a liquid-cooled engine equipped with a radiator and an oil sump,” says Eric Massinon, business development manager for Chicago Pneumatic Construction Equipment. “Proper maintenance and replacement schedules should be kept up for all filters, including the fuel filter and air filter, especially in dirty environments. Additionally, ensuring that the proper engine oil as well as the correct, clean fuel is used can go along way in maintaining the machine.”
Some manufacturers offer solar-powered light towers, which are more expensive up front, but are nearly trouble free.
“While diesel-powered light towers require periodic maintenance, solar-powered light towers are nearly maintenance free,” Siffring says. “They don’t require fuel, oil or coolant, and since they don’t have rotating parts, there is no wear. Aside from cleaning the lenses and solar panels, solar light towers require little effort, so they have the lowest total cost of ownership in the industry. They can run for as long as 30 hours on a full charge and feature an external charger for when there are fewer daylight hours.”
Proper setup and use are also important to keeping light towers running smoothly.
“Start with confirming that the unit is ready for towing and is towed properly,” Massinon says. “Once the machine is on site, proper setup is key. A lot has to be done between pulling onto the job site and starting it up. Users need to level the light tower and set up the outriggers properly. Then, before raising the mast, make sure the lights are positioned and adjusted to the desired position.
“Once the tower is setup and the mast is raised, ensure that all of the switches are turned off prior to starting the engine,” Massinon says. “Operators should always refer to the manufacturer’s instructions for startup; once the engine is running, it’s best to let the engine run for a few minutes before applying a load.”
Burman says, “This will cause the least stress to the mechanical and electrical components of the light tower, keeping it running longer and requiring less maintenance.”
All manufacturers stress that it’s imperative the machine is fully shut down before performing any type of maintenance.
“Diesel light towers are just like a generator; they produce lethal levels of voltage,” Siffring says. “So more in-depth repairs should be left to trained professionals.”
Burman reminds managers that although the generator is shut off, potential energy could be stored in the capacitor. “This should be handled cautiously. Make sure to follow any warning labels on the machine, as well as those laid out in the operators’ manual to keep from getting injured,” he says.
The bulbs themselves also need attention. Many units feature metal halide bulbs.
“Metal halide lamps, which are energy efficient, last as long as 20,000 hours and have the lowest failure rate of any type of traditional bulb,” Siffring says. “When bulbs or ballasts do need to be replaced, it’s important to order them from the manufacturer as they can vary from one to the other.”
Burman says there are pros and cons to the different types of light bulbs available for light towers. “The life expectancy of metal halide bulbs is better than ever due to the specific design of some lamps and the development of the parallel light fixture,” he says. “The 1,000-watt metal halide light bulbs have a rated life expectancy of approximately 10,000 hours in ideal conditions, and 1,250-watt metal halide bulbs provide more light, but they have a rated life expectancy of about 7,000 hours in ideal conditions.”
Replacement costs will vary, Burman says, with LED lights being the most expensive.
“LED bulbs are not replaceable,” Massinon says, “rather, the whole element must be replaced. They are easier to handle, however, since they do not burn hot.”
According to Marie Engstrom, associate product manager, Terex Aerial Work Platforms, intervals for changing depend on usage conditions.
“A general rule of thumb for good working conditions is a bulb life of about 10,000 hours,” Engstrom says. “Terex AL4L and A5L models come with LED panels, which have an expected life of about 50,000 hours. But before changing metal halide bulbs, make sure they are cool. Don’t touch them with bare hands, either, as oil can damage the bulb and decrease its life.”
Massinon adds “Oil from users’ hands can get on the lighting element and cause it to burn at a higher temperature. It’s also important to protect the bulbs from contaminants whenever possible—store replacements in a clean place, and only unpack them when using immediately. Make sure they’re properly secured to the light tower before use.”
Using common sense during transportation can also save light bulbs’ lives. Consider the wear and tear that can occur.
“The more you tow the light tower, the higher the chance the lighting element will break,” Massinon says. “A large part of that is based on how you secure and tow the machine. When towing, operators will ideally have the lamp socket oriented in a downward position. Also, ensure that the mast is all the way down to reduce bouncing during transit.”
Siffring says it’s important to remember to direct lights inward during transport. “This minimizes the risk of damage to the lenses or bulbs that can occur from rocks that get kicked up during travel.”
And don’t forget safety pins. “Make sure that safety pins are in all of the outriggers to prevent sliding during towing, that the safety chains are connected, and that the trailer lights are fully operational before towing,” Massinon says.
“The failure rate of any light bulb will ultimately depend on road and weather conditions along with other elements,” Burman advises. “Vertical towers can help reduce the shock and vibration, which will enhance the longevity of the light bulbs.”