This Yellow Bus Runs Green
All aboard for electric-powered transportation
Silent as a shadow, the 72-passenger Blue Bird school bus cruises at 50 mph down a rural road in the Rio Grande Valley. Propelled by two proprietary electric motors designed and built by Bob Ross and crews at New Core, Inc., and his former company, Jasper Electric Motors in Jasper, Alabama, the bus demonstrates the future of battery-powered transportation. “This works so well because of what a school bus does—driving a limited distance. It’s the perfect application for an electric-powered vehicle,” explained Ross, owner and president of New Core and a member of Magic Valley Electric Cooperative.
Traveling a fixed route of less than 30 miles, the quiet-running electric bus recharges at night during off-peak periods, when demand for electricity is lower. Instead of a diesel motor, the bus runs on 54 large batteries connected to synchronized motor drive controls that send alternating current to two 60-horsepower motors. A propane generator supplies backup power. Turning a big yellow school bus into a cool, green machine took only a good idea—and a year.
When gasoline exceeded the $4-per-gallon mark nationwide in 2008, Ross decided to tap the talent at the two electric-motor refurbishing companies to create a greener school bus, something cheaper to operate than the diesel-guzzling standard. With no fixed budget, the project’s prime asset was the employees’ years of expertise building industrial electric motor cores for transcontinental pipelines, coal mines and nuclear submarines.
“We can make everything but money,” Ross joked. “But this is our game. We’re motor men, electrical guys.” The Missouri native enlisted friends Don Wetzel and Greg Eschborn, both electrical engineers, to help design the motor and create the control system, respectively.
In 1992, Ross sold the electric core business he had founded 20 years earlier in Jasper, Alabama, to his children and retired to Palm Valley, west of Harlingen. Retirement lasted two weeks as Ross dived into his new business, New Core. “I didn’t like to play golf all that well,” he said. Soon he was building generator parts, and New Core, just north of Harlingen in Combes, grew to 25 employees.
In August 2009, when the prototype electric bus had 700 miles on it, Ross applied for a patent on the electric motor. The two shop-built motors that turn the single drive shaft sit under the bus floor between the first seats. The original transmission was left intact but was moved closer to the rear wheels. A 12-volt air compressor powers the air brakes. A 5-horsepower electric motor runs the power steering, lights, wipers and heaters. A vertical array next to the driver shows rpm and voltage; the motors run cool at 150 degrees Fahrenheit.
A propane generator fills the space where the engine once sat. When the battery bank is nearly depleted, the bus automatically switches to propane power with a slight hum. Charles Cornwell, an electrical engineer working with Ross, said the bus on a recent 130-mile trip used 25 gallons of propane and depleted the batteries. With propane at $1.50 per gallon and the cost of recharging at 10 cents per kilowatt-hour, the trial run cost about 22 cents per mile on battery power alone and 42 cents on hybrid power (electric and propane). The same trip diesel powered would have cost around 50 cents per mile.
Out on the road, the ride is so shockingly quiet that you wonder about your hearing ... until the vehicle’s shocks creak.
Ross and his team are still improving the vehicle’s performance and are planning to switch to lithium batteries.
Once lithium battery partners are lined up, Ross said New Core and possibly other companies will be ready to begin building electric motors to be retrofitted into school buses.
Based on the prototype’s performance, the electric bus from a tiny Texas town has the potential to dramatically change the national public transportation picture.
Eileen Mattei lives in Harlingen.