Perhaps no other technological development in the past 40 years has done more to revolutionize overhead crane design than the AC Variable Frequency Drive (VFD). Today’s Variable Frequency Controls and Flux Vector Motor Controls have become the industry standard for crane control.
AC Variable Frequency Drives provide greater reliability, enhance performance, improve production throughput, prolong equipment life, and reduce maintenance costs, parts, and personnel in a variety of ways, including:
- Reducing the characteristic high starting currents of AC induction motors
- Minimizing the shock effect on both the load and the equipment
- Offering features, such as programmable acceleration and dynamic braking that:
- Produce softer stops and starts
- Assure smooth transitions between speed steps
- Reduce brake wear and required maintenance
- Embedded Anti-Sway control
Crane-specific firmware, drive support tools, and wired/wireless communication with various peripheral devices provide valuable monitoring, status, performance, and diagnostic information.
Features are built-in and individually selectable:
- Reverse Plug Simulation
- Stall Prevention
- Inching Control
- Weight Measurement System
- Micro-Positioning Control
- Static Stepless Simulation
No two applications are the same. Variable Frequency Drives provide users with a variety of operating modes and a wide range of options. Most single-speed squirrel cage motors can be controlled by VFDs, including conical-rotor motors used by many European hoist manufacturers. Multiple control modes (two, three, and five step or infinitely variable speed) allow for changing the operation to suit the needs of specific applications or the desire of individual operators. A wider range of selectable speed choices (up to 1500:1) are available to the user compared to the fixed speed ratios provided by the typical two-speed motors (2:1, 3:1, or 4:1) or micro-drives (10:1).
Safety is built into modern Variable Frequency Drives. They include features that:
- Reduce the possibility of lifting an over-capacity load
- Minimize or eliminate dangerous load swing
- Prevent overheating of the motor
- Detect and minimize rapid increases in motor torque
- Provide safeguards that limit unauthorized modification of drive parameters or programming unsafe parameters.
Today’s technology provides a cost-effective means to make your crane more efficient, productive, and safer.
Learn more about VFDs at www.magnetekmh.com.