Bowden Bros. Ltd. has developed a completely new design of Earth Fault Indicator for use on high voltage distribution networks. It uses modern electronic design concepts and makes mechanical flag indicators obsolete. BEEFI is constructed with the electronic relay integrated within the body of the balanced core current transformer, making it more compact, and less expensive instrument to manufacture. The electronic relay can be fitted to either a split core or a solid core TV Armstrong CT. The CT resin moulding is extended by the addition of a resin trough, into which the electronics are encapsulated with a polyurethane encapsulant. The Lithium Thionyl Chloride battery, which is in itself separately encapsulated, is housed within a recess in the main body of the CT. This makes it easily accessible for change of battery when it becomes necessary after 8-10 years of service. A replacement battery pack is available from Bowden Bros. The internal power source offers low cost installation, avoiding the need for an external supply, as well as giving flexibility on where the unit can be mounted.

• Integrated construction
• Cost savings on earlier models
• Simple to install, requiring no additional wiring
• Flashing Lamp Alarm
• Auto reset after fixed time
• Independent short circuit tested to 16KA for 3 secs
• Maintenance Free service life 8-10 years
• Replaceable Lithium battery power supply
• Totally encapsulated electronics for environmental protection
• Preset 35msec delay to avoid incorrect operation on switching transients
• Accurate out-of-balance trip level

Weather Protection
The electronics being encapsulated offer total environmental protection. However, in addition the resin trough is secured to the body of the CT with six Allen headed screws, offering a greater level of security. The trough to the CT joint is sealed with a rubber gasket.

Flashing Lamp Alarm
A lamp flashes when the BEEFI is alarmed by the passage of current in the cable sheath. The operation of the alarm is delayed for 35ms to avoid incorrect operation from spurious sheath currents caused by switching transients.

It automatically resets to the alert mode after a period of 3 hours.

The alarm circuit can also be restored to the alert mode by passing a small magnet across the front of the module.

If required the alarm period can be extended from 3 hours to 6 hours at the time of manufacture.

Testing
The correct operation of the battery can be checked by holding a magnet on the front of the box. The lamp will light continuously until the magnet is removed.

We can supply a portable test unit, which by inducing current in the CT, can simulate a fault and test the operation of the complete installation. (Bowden Portable FF1 Test Unit). It is essential that every BEEFI unit is checked for correct operation when first installed or after changes are made to the unit. The installation can be checked using suitable test equipment or the Bowden Portable FF1 Test Unit.


Specification
Trip Current:- 35A within the range 20 to 50A
Trip Delay:- 35mS (Nominal)
Reset Time:- 3 hours +1-- 15 mm Optional 6 hours
Lithium Chloride Battery:- 8-10 years (Assumes 1 operation/month)