Adjustable-frequency DrivesSource: The Graham Company
This literature covers the VLT Series 3000 adjustable frequency 1- to 250-hp constant torque or 1- to 300-hp variable-torque drives--including specifications. The drives feature RS-485 communication, PID and set-point control, a DC link reactor, output reactors, high-frequency operation, IGBT output for high efficiency and motor quiet, diode-bridge high-power factor output, and a common user interface. A back-lit, three-line alphanumeric display shows process variables. The manufacturer also cites the following drive attributes: a current sine wave for full-rated motor voltage at rated frequency; a rated output voltage that holds under a 10 percent nominal line voltage drop; motor add-on or removal on the fly; electronic l2t Class 20 motor overload protection throughout the speed range; unlimited switching on the output; ground-fault and phase-to-phase short-circuit protection; one drive/multiple-motor operation; synchronization with a spinning motor up to 100 percent speed in either direction; NEMA 1, NEMA12 and chassis-mount availability.
Graham Company, a member of the Danfoss Group, P.O. Box 23880, Milwaukee, WI 53223. Tel: (414) 355-8800; Fax: (414) 355-6117.