New Motor for Overhead Cranes and Hoists

Uxbridge, Mass.-based Lenze Americas, a manufacturer of electrical and mechanical drives, motion control and automation technology, has launched the L-Force Three-Phase MF Motor design for operation with a frequency inverter, and suitable for use on overhead cranes and hoists. The motor can be up to two sizes smaller than conventional asynchronous motors with the same rated power, according to the manufacturer.

"The MF motor features a wide speed setting range of 1:24, about twice as fast as conventional motors," said Wayne Lazzerini, mechanical product manager. "Due to the higher rotational speed of the MF motors, a size 71 device, for example, is sufficient for a rated power of 1.5 kW that would otherwise require a size 90 conventional three-phase motor."

Available in power ranges from 0.55 to 22 kW, MF three-phase AC motors bridge the gap between conventional AC motors and the high dynamic performance of servo motors. With efficiency levels of 94 to 98 percent, the right-angle and in-line gearboxes ensure that energy output by the motor is transferred to the application with minimal losses, according to the manufacturer. A correspondingly higher gearbox ratio compensates for the improved motor speed.

MF motors are compatible with either a central control cabinet drive or a decentralized motor inverter. The smaller frame size of the combined Lenze L-force drive package makes the design more cost-effective. To fully leverage the advantages, Lenze recommended combining the MF motor with an 8400 series inverter, which comes equipped with its energy saving VFCeco (Voltage Frequency Control Economic) function. VFCeco automatically adapts the magnetizing current of the MF Motor to the operating conditions, increasing efficiency during partial load and reducing energy use by up to 30 percent.