Fairchild International, a U.S.-based manufacturer of underground mining equipment, has produced battery-powered DC scoops since the early 1980s. With 17 different models available, Fairchild offers a size to fit any coal mining operation, making it the leader in the industry.
Given that many different hydraulic systems recommend the use of either frequency converters or cyclic control (soft starter technologies), the question must be asked - Which one of these solutions is the most cost-effective in reducing energy consumption and providing the most satisfactory payback time?
One of the driving forces behind the industrial revolution was the invention—more than a century ago—of the electric motor. Its widespread use for all kinds of mechanical motion has made life simpler and has ultimately aided the advancement of humankind.
And the advent of the inverter that facilitated speed and torque control of AC motors has propelled the use of electric motors to new realms that were inconceivable just a mere 30 years ago. Advances in power semiconductors—along with digital controls—have enabled realization of motor drives that are robust and can control position and speed to a high degree of precision. The use of AC motor drives has also resulted in energy savings and improved system efficiency. This paper reviews the development and application of inverter technology to AC motor drives and presents a vision for motor drive technology.