The wide range of magnets and their respective applications demand a wide range of control gear to perform the necessary sequence of switching and other functions determining the speed of magnet operation and overall efficiency of electromagnetic handling equipment.
General handling of material does not normally warrant sophisticated control equipment.
In the case of Small Circular Magnets, switching can be performed by a Heavy Duty Switch incorporating a series resistance and field discharge unit. This switch is of relatively small physical dimensions, a factor essential to the applications for which these magnets are used, e.g. fork-lift trucks, hoistblocks, etc.
Where remote control is required, it is necessary to have a contactor panel operated from a Master switch. This may be of several types, e.g. push-button, lever, or foot-switch. Two main types of Contactor Control Gear are available depending on magnet power consumption.
The small unit comprises a sheet steel enclosure containing a contactor and resistance panel which is rated for operating magnets up to 6 kW. consumption. Due to its compact form, this unit is generally used on Mobile crane installations where physical dimensions are a consideration.
Above 6 kW rating, magnets are operated by a Heavy Duty type Control Gear which comprises a totally enclosed contactor panel incorporating a series and discharge resistance unit mounted in a ventilated sheet steel enclosure. Both types of combined contactor panel incorporate mechanically and electrically interlocked contactors, filled with powerful magnetic blowout coils to increase contact life.