School Bus Fleet

October 2014

A management & maintenance magazine for school transportation fleets

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50 S C H O O L B U S F L E E T • O C T O B E R 2 0 1 4 The H3X takes the place of an H3 halogen bulb, which is common to school bus eight-way warning lights. It employs the inner refector as a built-in component for heat dissipa- tion with a circuit board/driver pot- ted into the rear of the unit to further simplify installation. The H3X fxture contains nine sur- face mount display (SMD) LEDs on a single circuit, which, according to Ul- traLED, addresses out-of-service cri- teria and provides an LED warning light with a service life of up to 50,000 hours of product life — compared to 300 hours for the halogen counterpart. Maintenance benefts Billingsley says that the longer ser- vice life for LED lights reduces bus downtime and labor costs, which is es- pecially vital for shops whose bus-to- technician ratios have increased and whose number of spare buses has de- creased in recent years. "Any of the labor utilization that can be allocated to preventive maintenance and large jobs — and not to changing bulbs — it's a greater use of [the tech- nicians'] time," he says. "The savings is found in the labor and not needing to have their technicians replace the same bulb two or three times within the same school year." Doug Campbell, OEM account man- ager for Safe Fleet's Specialty Manufac- turing (also known as SMI), notes that in addition to the longer life of LEDs essentially instantaneously. "In our periphery, we perceive change much better," Riesebosch says. "So when something changes rapid- ly in our peripheral vision, we can see that quickly." In addition to the quicker turn-on time, LEDs tend to be brighter than in- candescents, so they are more visible, even in the daytime, according to TRP Development Manager Jeff Hughes. Also, he adds, LEDs' "lower power draw means that your hazard lights can fash longer if your vehicle be- comes disabled." Less energy needed More effcient use of energy is an- other selling point for LEDs. They use a fraction of the power that an incan- descent light of a similar size uses, Hughes says. According to Riccio, 1157 incandes- cent and H3 halogen bulbs typically used in traditional school bus light- ing applications draw 2.1 to 2.9 amps, while LED lights draw 0.01 to 1.5 amps, depending on the application. "LED lights also offer substantially less voltage consumption than their traditional counterparts," Riccio says, "which translates into less wear and tear on bus electrical systems (i.e., re- placing expensive batteries, alternators and switches with less frequency)." LED retroftting Some operations are opting to switch from incandescent to LED bulbs on their existing buses. Billingsley of Ul- traLED says that the retroftting activ- ity is facilitated by the fact that there are "so many products now that work with existing technology and make it so easy to upgrade to LED." An example is UltraLED's new H3X LED upgrade for school bus warning lights. The halogen-to-LED warning light upgrade uses the same concept as the company's stop-arm LED upgrade bulb, using the existing fxture for a di- rect interchange. LED LIGHTING Research has found that driver reaction time to LEDs is signifcantly faster than to incan- descent lights. Pictured is SoundOff's 7-inch LED amber warning light. LED standard update eyed for NCST S tandards for LED lighting is a topic that may be addressed at next year's National Congress on School Transportation (NCST). Safe Fleet's Specialty Manufacturing has submitted new, performance- based language for LEDs to the NCST committee to consider adoption for the 2015 school bus standards. Corbin West, senior reliability and design engineer for Safe Fleet's bus divi- sion, explains that there is a need for updates in how LEDs are measured and categorized. To illustrate that point, West says that the fash tubes that have traditionally been used in roof-mounted strobes are categorized in terms of joules, which is a measurement of how much energy the light unit uses. When it comes to LED strobes, however, categorizing by joules doesn't work, because LEDs are able to provide more light output with much lower power consumption. West gives an example: "An LED strobe that consumes 1 joule of en- ergy can be signifcantly brighter than a fash tube strobe using 10 or 15 joules." The proposal that Specialty submitted to NCST seeks to clearly defne LED strobe lamp specifca- tions utilizing the current SAE J845 specifcation. Specialty's new roof- mounted LED strobe exceeds the SAE J845 Class II rating, according to the company. Specialty Manufacturing's new roof-mounted LED strobe exceeds the SAE J845 Class II rating, according to the company.

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