Electricity: electrical systems and devices – Safety and protection of systems and devices – Transient responsive
Reexamination Certificate
2006-01-23
2008-12-09
Sherry, Michael J (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
Transient responsive
C361S018000, C361S091200, C361S091600
Reexamination Certificate
active
07463470
ABSTRACT:
An electrical barrier (10) for connecting a power supply to electrical equipment situated in a potentially explosive atmosphere comprises an input (12), output (13), a shunt Zener diode (14), a fuse (15), an output resistor (16) and the sensor resistor (11). The Zener diode (14) is operable to limit the output voltage of the barrier. In some embodiments multiple Zener diodes are used if desired or appropriate. The output resistor (16) acts to limit the maximum output current whilst the fuse (15) acts to prevent operation of the barrier in the event of an excessive input. The sensing resistor (11), being in series with the Zener diodes (14), allows the current flowing through the Zener diode (14) to be determined. The value of this current is then used to regulate the voltage input to the barrier (10). By using such a sensing resistor in series with the Zener diode (14), the voltage on the Zener diode (14) can be controlled so that the desired current flows. This advantageously requires that no allowance or adjustment for the tolerance of the voltage regulator or the Zener diode is required and furthermore no allowance or adjustment needs to be made to accommodate the temperature coefficient of the Zener diode (14).
REFERENCES:
patent: 4554500 (1985-11-01), Sokira
patent: 5365420 (1994-11-01), Cadman
patent: 19846757 (2000-06-01), None
European Patent Office Search Report, Application No. 06250333.9-2207, Jul. 21, 2006.
Barlow Josephs & Holmes, Ltd.
Patel Dharti H
Pepperl & Fuchs GB Ltd
Sherry Michael J
LandOfFree
Electrical barrier does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrical barrier, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrical barrier will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-4045717