The majority of Class 4 and specialized cranes around the world operate on an AC supply and are powered by standard AC slip-ring motors. Whereas the combination of frequency drives and cage motors have made strong inroads, many users adopt a conservative approach, and hold a preference for a somewhat lower order of technology, but with a proven track record in severe industrial environments.
The measure of a successful system lies in it’s adaptability to a large variety of industrial applications. It will have the following important qualities:
1- Excellent control: for both hoist (vertical) and travel (horizontal) drives.
2- Modular construction: with user-friendly format for power and control
assemblies.
3- High reliability: simple rugged construction with effective zero
maintenance.
4- Safety of operation: inherent protection against over-speed, tacho failure,
and phase failure.
5- Versatility: application to any size and quantity of motor, and to all voltage
ratings.
6- Ambient tolerant: insensitive to high ambient temperatures – 600C.
The above are features inherent in AC10 control from HP Resistor Control in association with Saftronics (Pty) Ltd. The system is in extensive use in steel plants throughout South Africa, as in steel-producing complexes in Brazil, India and Malaysia.