Browse Prior Art Database

Ground Fault Protection Circuit for Power System

IP.com Disclosure Number: IPCOM000074212D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Parrish, M: AUTHOR

Abstract

This circuit checks the continuity of the ground wire and its maintenance at ground potential, and removes the machine power if for any reason the ground wire is opened and not maintained at ground potential. Under normal circumstances contacts 10 are closed, and ground and neutral wires are shorted together. The shorting of the ground and neutral wires effectively short circuits capacitor 12 and prevents it from charging. If for any reason the ground-neutral connection is broken capacitor 12 will begin to charge in response to the current flow through resistor 14. As capacitor 12 charges and reaches a preset voltage level, trigger device 16 will break down and conduct the current stored in capacitor 12 to triac 18. This capacitor discharge current will cause triac 18 to conduct for one-half cycle in each direction.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 85% of the total text.

Page 1 of 2

Ground Fault Protection Circuit for Power System

This circuit checks the continuity of the ground wire and its maintenance at ground potential, and removes the machine power if for any reason the ground wire is opened and not maintained at ground potential. Under normal circumstances contacts 10 are closed, and ground and neutral wires are shorted together. The shorting of the ground and neutral wires effectively short circuits capacitor 12 and prevents it from charging. If for any reason the ground-neutral connection is broken capacitor 12 will begin to charge in response to the current flow through resistor 14. As capacitor 12 charges and reaches a preset voltage level, trigger device 16 will break down and conduct the current stored in capacitor 12 to triac 18. This capacitor discharge current will cause triac 18 to conduct for one-half cycle in each direction. The current which flows through relay trip coil 20 in response to the firing of triac 18 will pick the relay and open contacts 10. Resistor 22 bypasses relay trip coil 20 to de-energize the coil after the triac has turned off.

In the event the neutral and ground wires are reversed, triac 18 will see a voltage across resistor 24 and upon turning on will conduct thereby tripping contacts 10 in response to the energization of relay trip coil 20. The primary advantages of this circuit over prior devices is the immediate power removal upon fault detection and the removal of power if the line and neutral wire...