Lifting magnets, power sources and electrical control systems: FAQ with Winkle Industries

Some magnets are simple, like the small, hand-held versions that hold paper clips or which affix photos, calendars and notes to metal. Magnets attached to mobile material handlers to lift metal are much more complicated. Following are answers to some of the most popular questions often asked about lifting magnets, power supply sources and electrical control systems. 

Is there equipment available that can help extend magnet service life?
Yes, there are monitors and meter packages that aid in the safe use and prevention of premature magnet failures. Both devices provide operators the ability to verify electrical performance. The primary difference is that the monitor submits alerts when magnet current limits have been exceeded and can disable subsequent lifts. Both pieces of equipment are valuable tools for extending the service life of electro-lifting magnets.

2. How can I minimize or prevent damaging my magnet power leads/cable?
The most effective way to prevent damage to magnet power leads is through the use of a cable protection system. The Bullet Cable Protector (shown above) prevents abrasions, nicks, cuts and heavy impacts which are leading causes to premature magnet and electrical system failures. 

3. What are the differences between DC constant potential and solid state magnet controllers?
A DC constant potential controller utilizes electro-mechanical components to safely charge and discharge magnetic fields. These units historically require constant maintenance and do not provide any protection or diagnostic features. Solid-State controllers are virtually maintenance-free, "intelligent" devices that protect magnets, power sources and personnel from potentially dangerous conditions. These units also increase cycle times and throughput with faster charge times and cleaner drop cycles.

4. What are the advantages of an AC to DC magnet power source?
An AC to DC power source utilizes a maintenance-free, brushless AC generator. The output voltage is converted through the use of a solid-state controller to produce DC magnet power. AC versus DC generators offer a wider operating speed range, and output voltage is less dependent on the rpms. Additionally, AC units are dimensionally smaller than equivalent Kw-rated DC generators. 

5. Why is a magnet inspection program important?
A magnet inspection program is a primary tool for proactively aiding in safe use, preventing high costs of repairs and ensuring optimum performance. The program should incorporate verifying and documenting electrical readings such as current, resistance and meg-ohms at consistent intervals. It is equally important to include visual inspections of the mechanical condition of magnets (i.e. welds, wear depth, chain wear, etc.). Both procedures will capture minor problems before they become major issues.

Mark Volansky is Winkle Industries'director of sales. 

This article was originally published in the May/June edition of Recycling Product News, Volume 27, Number 4.