Pepperl+Fuchs KFD2-EB2 Power Feed Module for Power Rail

KFD2-EB2 power feed module for the K-System Power Rail

The KFD2-EB2 supplies the Universal Power Rail of the K-System with 24 V DC at up to 4 A and monitors the rail for faults. Every isolator clipped onto the rail takes its supply from it, and the module reports a collective fault from any connected device through a relay output. It is the supply and diagnostic heart of a rail-based isolator installation.

Seven Star LLC supplies the KFD2-EB2 in Oman and the GCC as an independent supplier in Muscat. The following sections explain what the module does, how it is rated and what to check when sizing a rail.

KFD2-EB2 designation

The KFD2-EB2 is a type designation of the Pepperl+Fuchs K-System, named in the datasheet as a power feed module, an interface for the Power Rail. The 20 mm housing holds a replaceable 5 AT fuse and two terminal groups for supply input. The datasheet states that the module is compatible with all versions of the Power Rail.

From a safety point of view, the module has no dangerous failures; the safe state of the supplied isolators is the de-energized state, so the module does not influence the SIL calculation of the loops on the rail.

Technical specifications of the KFD2-EB2

How the KFD2-EB2 feeds and monitors the rail

The module takes 24 V DC from the plant supply, passes it through a replaceable fuse to the three-conductor rail insert, and so supplies every connected isolator through the rail contacts. Two of the three conductors carry the supply, the third carries the collective error signal. Each isolator on the rail can pull this line low when it detects a fault, such as a lead break, and the feed module converts that into a relay contact for the control system.

The relay can be configured for normally-open or normally-closed operation with switch S1. A green LED shows power and a red LED lights during a fault. The maximum rated operating voltage of the isolators on the rail must not be exceeded by the supply.

The 4 A output limit means that the total current of all modules on the rail must be added up. With the 80 % utilization recommendation for the fuse, the practical design limit is around 3.2 A on one feed module, which can be split by placing several feed modules on separate rail sections with an insulation spacer.

Rail design with the KFD2-EB2

A rail section such as the UPR-03 carries up to 4 A. Segments can be separated with UPR-I insulation spacers if different supplies or different fault zones are wanted. All K-System modules that list Power Rail supply, for example the KFD2-STC5-1, KFD2-USC-1.D and KCD2-SR-2 on this site, can be fed through the same module.

The datasheet indicates that the combination of K-System modules and the rail can be mounted in Zone 2, which is why this module carries an Ex ec nC marking.

Selection and ordering checklist for the KFD2-EB2

• Add up the supply currents of all modules on the rail and stay below 4 A (80 % fuse utilization)
• Decide on fault relay logic: NO or NC
• Check the supply voltage range and the maximum voltage rating of the rail modules
• Check approvals and marking required for the area
• Plan rail separation with insulation spacers if needed
• Provide spare fuses

Installing the KFD2-EB2

Mount the module at the end of the rail section or in the middle, connect the supply to terminals 8 to 12 and the fault relay to the PLC input. Set switch S1 for the relay logic. Verify the voltage on the rail with a meter and trigger a fault in one of the isolators, for instance by breaking a field loop, to check that the fault relay operates.

Keep spare fuses of the stated type. A blown fuse indicates an overload or short circuit on the rail, which should be traced before replacing it.

Typical applications in Oman and the GCC

Power feed modules form part of nearly every K-System marshalling cabinet in oil and gas, power and desalination plants. Using a rail instead of daisy-chained wiring reduces both wiring time and the risk of a loose supply wire in a cabinet that is subject to vibration or thermal cycling. The -40 to 70 °C range supports cabinets exposed to extreme Gulf summer temperatures.

Power Rail components

From the datasheets.

Information to send with an RFQ for the KFD2-EB2

Please include the following.

• Number of modules on the rail and total current
• Supply voltage and fault logic
• Area marking requirement
• Quantity and delivery date

Documents and quotation

The manufacturer datasheet for the KFD2-EB2 is attached on this page, so the electrical data, terminal assignment and ambient limits quoted above can be checked against the original document before an order is placed.

Seven Star LLC supplies Pepperl+Fuchs products in Oman and the GCC as an independent supplier in Muscat. Send the quantity, the signal types and the project delivery date, and we will confirm availability and lead time in a written quotation.