Installing Ferrites and Toroids

Overview of EMC Reduction Components

All installation require the use of ferrites and toroids. These devices are required to meet the electromagnetic conductance (EMC) regulations that are in effect for the country in which the system is installed.

Ferrites and toroids are made of a conductive carbon type material that reduces EMC frequency bandwidth. Ferrites and toroids must be installed on the interface cable of certain peripheral devices or circuit cards.

A ferrite is a 1 inch (2.5 cm) rectangular device. It is available in split and solid ferrite forms. A special snap-back protective cover is used to install and keep the halves together.

A toroid (Type A) is a 2.5 inch (6.4 cm) circular ferrite. Toroids are made of a highly conductive carbon type of material that is very brittle. If a toroid ring fractures, it should immediately be replaced.

This section contains the following installation procedures:

• Installing Toroids
• Installing Ferrites

Installing Toroids

 

Handle all toroids with care. They are easily broken. Do not use any that are broken or fractured. Damaged toroids are no longer effective for EMC control.

When installing toroids or ferrites:

• See Toroid Installation. Place toroids as close as possible to the computer chassis.
• Minimize the amount of cable between the toroids and the chassis.
• Wrap cables as tightly as possible. Do not leave large amounts of slack in the loops.

To install a toroid:

1. Wrap each modular cable tightly around the toroid.
2. Secure the cables with a small cable tie to reduce cable movement.
3. Trim the cable tie.

Installing Ferrites

 

Handle all ferrites with care. They are easily broken. Do not use any that are broken or fractured. Damaged ferrites are no longer effective for EMC control.

When installing ferrites:

• See Ferrite Installation. Place ferrites as close as possible to the computer chassis.
• Minimize the amount of cable between the ferrites and the chassis.
• Wrap cables as tightly as possible. Do not leave large amounts of slack in the loops.
• Use large cable ties behind the ferrite to help them to stay in place.

To install a ferrite:

1. See Ferrite Installation. Open the ferrite by gently pulling the fastener away from the body of the ferrite.
2. Place the cord or cable in the groove inside the ferrite.
3. If the cable is to be wrapped around the ferrite, wrap the cable tightly around half of the ferrite and place the cable into the groove. See Ferrite Installation.

If the cable is to be wrapped around two ferrites, make sure the ferrites are close together. See Ferrite Installation.
 


Note: It may be necessary to space ferrites differently on modular cables that are being installed in close proximity to each other.

4. Gently snap the ferrite shut.
5. Attach a large cable tie directly behind the ferrite to secure it.
    
   

   Note: If the cable is wrapped around the ferrite, no cable tie is required.

6. Trim the cable tie.

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