Fuseless intrinsic safety barrier
First Claim
Patent Images
1. In an intrinsic safety barrier circuit module having:
- a first pair of pole connectors adapted to be connected to an external power supply and to an external signal conditioning unit; and
a second pair of pole connectors adapted to be connected to at least one input of an industrial process situated in a hazardous area;
the combination of;
a plurality of electrical components connected in circuit between said two pairs of pole connectors for conveying energy and information therebetween and for applying to said second pair of poles voltage and current of limited magnitude, said plurality including at least one positive temperature coefficient resistance device connected to one of said first pole connectors and operative in said module for limiting overcurrent from said connected one of said first pole under faulty conditions with said external power supply;
with at least one of said electrical components being a voltage limiting device, said voltage limiting device being mounted in circuit after said one positive temperature coefficient resistance device, the time constant of said resistance device being smaller in response to an overcurrent than the time constant for which said voltage limiting device is exposed to destructive action by the same overcurrent; and
with all of said electrical components of a plurality being encapsulated as a unit to form a fuseless intrinsic safety barrier circuit module.
1 Assignment
0 Petitions
Accused Products
Abstract
An encapsulated intrinsic safety electric barrier in which at least one positive temperature coefficient resistance device is embedded in the insulation together with the other electrical components of the module.
31 Citations
1 Claim
-
1. In an intrinsic safety barrier circuit module having:
-
a first pair of pole connectors adapted to be connected to an external power supply and to an external signal conditioning unit; and a second pair of pole connectors adapted to be connected to at least one input of an industrial process situated in a hazardous area;
the combination of;a plurality of electrical components connected in circuit between said two pairs of pole connectors for conveying energy and information therebetween and for applying to said second pair of poles voltage and current of limited magnitude, said plurality including at least one positive temperature coefficient resistance device connected to one of said first pole connectors and operative in said module for limiting overcurrent from said connected one of said first pole under faulty conditions with said external power supply;
with at least one of said electrical components being a voltage limiting device, said voltage limiting device being mounted in circuit after said one positive temperature coefficient resistance device, the time constant of said resistance device being smaller in response to an overcurrent than the time constant for which said voltage limiting device is exposed to destructive action by the same overcurrent; and
with all of said electrical components of a plurality being encapsulated as a unit to form a fuseless intrinsic safety barrier circuit module.
-
Specification
-
- Resources
Litigation Campaign Assessment
Thank you for your request. You will receive a custom alert email when the Litigation Campaign Assessment is available.
×
-
Current AssigneeRosemount Analytical, Inc. (Emerson Electric Company)
-
Original AssigneeWestinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
-
InventorsWeberg, Lloyd E.
-
Primary Examiner(s)Moose, Jr., Harry E.
-
Application NumberUS05/741,438Time in Patent Office599 DaysField of Search361/56, 361/98, 361/90, 361/91US Class Current361/56CPC Class CodesH02H 9/008 Intrinsically safe circuits
