The Ferrogard range of magnetically-actuated safety switches offers noncontact reliability together with tolerance to misalignment and fail-safe operation. With versions sealed to IP67 some Ferrogards are suitable for environments where hygiene is of paramount importance.
Unlike some magnetic switches, the Ferrogards have protected safety contacts to ensure that they cannot fail in a manner that causes danger. Some versions have independent auxiliary signal contacts to indicate the machine and guard condition.
It should be noted that all Ferrogards have internal overload protection that cannot be reset. They should be protected by an external fuse rated as shown in the specifications table.
Ferrogard 1, 2, 6, 9, 10, 20DC and 21
These safety switches are supplied sealed to IP67 and pre-wired. The cable stuffing gland locking nut has Pg7 thread, and may be removed and an adaptor fitted to allow the fitting of a conduit or other cable protection.
Ferrogard types 1 and 6 feature a single safety contact. The Ferrogard 6 incorporates a unique slim design of switch and actuator case. The switch can be operated on either of two faces and mounting holes allow for different mounting configurations.
Ferrogard 3, 4 and 5
These versions offer the facility of terminal connections. The robust ABS housing is sealed to IP65 and can be drilled for cable entries wherever required. The PCB switch assembly is encapsulated in the lid to ensure switching characteristics similar to Ferrogard 1, 2 and 6. The lid is secured with anti-tamper screws. Top-quality terminals with clamp plates are provided within the enclosure, clearly marked to facilitate simple and safe installation. Note that lift-off guards require good alignment when using tongue actuated interlock switches. It is important to note that on some installations where it may be possible to lift the guard without actuating the interlock, additional interlocks on opposite sides may be required.
Ferrogard GS1, GS2 & GD2
Developed for heavy-duty applications, the GS1 uses the same type of reed as the other Ferrogards but is housed in a stainless-steel body. The GS2 offers the same characteristics as the GS1 but in an Ex housing for use in hazardous atmospheres. The FRS GD2 is also now available with various contact arrangements for arduous environments. Some Ferrogards are now available with a Brad Harrison connector, which gives quick connection for ease of installation.
Note that under the requirements of the Machinery Directive all machinery must undergo risk assessment to determine the necessary level (or category) of the safety-related control system or hazard-avoidance measures. Whilst the Ferrogard does comply with the requirements of EN 1088, it may not be suitable for all types of machinery or environments. Where magnetic materials are present or if it is foreseeable that, through machine function or use, Ferrogard operation by magnets other than the supplied actuator is possible, then use of an alternative Guardmaster switch is recommended.
Other noncontact options include Sipha or Ferrocode (for Category 3), which utilise additional coding techniques preventing them from being overridden by simple means. Alternatively additional measures may be taken to prevent the Ferrogard being easily bypassed. Consideration should be given to the recommended installation example given in the instructions and those in EN 1088.
For more information: Jeff Sandison, Rockwell Automation, 011 654 9700, [email protected]
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