In general, when new technology is integrated into a market, it tends to come in on the high side of the spectrum, i.e., a large or complex product where additional costs can be more easily absorbed or passed along. But that's definitely not how Terex Corp. approached it in the case of its new JL100 light tower.
Targeted firmly at the lower cost end of the company's light tower product line for markets such as rental and roadbuilding, the new JL100 tower incorporates a new permanent magnet alternator system that provides the power for four 1000 W metal halide lamps that can effectively provide lighting for 7.5 acres.
While permanent magnet alternators are not especially new--they have been used in military equipment for some time and have been seen off and on in very select commercial applications--this is one of the first times they have been applied in such a cost-sensitive arena as light towers.
"It's beautiful technology for what we're trying to do," said Robert Schaefer, director of sales, marketing and customer support for Terex Light Construction. "What we really did with this product is put ourselves in the shoes of our customer. We had a lot of 'leave your feelings at the door' meetings with our customers.
"What they told us was, you guys make a great light tower, but we don't need a full-featured light tower to meet our needs. We love having all of those receptacles and all that electrical capacity, but we don't need it and we really don't want to pay for it.
"So rather than take an existing product and try to make it something it's not, we decided to come up with a different concept altogether."
That different concept was an extremely simple machine that consists of little more than the engine, the alternator, some basic controls and a frame to hold it all together.
The JL100 light tower is powered by a two-cylinder, liquid-cooled Kubota Z602 diesel engine that is EPA Tier 2 ready. The 0.599 L engine is rated 13.5 hp at 3000 rpm in most applications, but here is operated at 2500 rpm for an output of approximately 11 net intermittent hp. The engine package includes a Copar radiator, Donaldson air cleaner and Nelson muffler.
Replacing the engine flywheel is a brushless, bearingless permanent magnet alternator that was developed by Newage AVK SEG. Much smaller than a conventional alternator, it is just 13 in. in diameter, 6.5 in long and weighs 81 lb. "It's an axial type machine based on a permanent magnet material," said Dr. Nazar Al-Khayat, chief engineer, research and development at Newage AVK SEG. "It's very much a dedicated machine for an application.
"Because it is a permanent magnet generator, it is more compact," Al-Khayat added. "It requires no electronic control because it has been designed to cope with a specific load. There is no excitation control needed because the magnets are already switched on all the time. It's mechanically integrated to the back end and crankshaft of the engine, so there is no need for a flywheel."
Along with the generator electronics, the system allowed Terex to eliminate the ballast units found on conventional light towers. "That's a major cost driver that we were able to leave out," said Schaefer. "Standard light towers at 60 Hz all have ballast units. With this direct system, we've been able to eliminate the need for ballast units and the cost of them as well.
"There is also a performance benefit. With the ballast and capacity functions removed, the lamps actually light faster. The striking time is nearly half of that of more complex units. And one of the other reasons this is so exciting is that because of the direct alternator design, it doesn't matter how fast you're running the engine. That takes 50 and 60 Hz out of the equation and opens it up for us to sell easily into Europe. Even unrelated to the electrical technology, with this design, the unit is less than 1750 lb., which lets us avoid a number of the European road regulations."
The alternator system was in development for approximately a year, according to Al-Khayat. "This concept came out of our variable speed program which we have been working on for quite some time," he said. "It has allowed us to move away from the 50 and 60 Hz to a higher output by providing the right impedance and softening the machine so it provides the right striking characteristics. It's also very durable. Light towers typically clock in a lot of service and this can accommodate that quite well."
The JL100 light tower controls consist of a simple instrument panel that incorporates a Grasslin hourmeter, on-off switch and switches for the individual lamps. A 30 gal. fuel tank provides more than 70 hours of run time under normal conditions, the company said. The mast section can be erected and extended to a height of 30 ft. though use of a dual winch system and the lights can be rotated a full 360[degrees] for maximum coverage. A manually operated four-point outrigger system is designed to steady the unit in windy conditions.