Patent ID: 7265960
Filing Date: 2007-09-04
Classification: H01H,H02H

Abstract:
1. A drive circuit for a trip coil of an electrical switching apparatus including a trip signal, said drive circuit comprising: an alternating current input adapted to receive an alternating current voltage; a first rectifier adapted to provide at least one direct current voltage from said alternating current input; an energy store adapted to provide a first direct current output from the at least one direct current voltage of said first rectifier; a circuit monitoring said alternating current input and said first direct current output and providing a second output from one of said alternating current input and said first direct current output; a second rectifier responsive to said second output and said trip signal to provide a third direct current output adapted to drive the trip coil of said electrical switching apparatus; and wherein said first direct current output has a direct current voltage; and wherein said circuit monitoring said alternating current input and said first direct current output comprises a first sensor monitoring said alternating current input, a second sensor monitoring said first direct current output a first contact responsive to said first sensor for outputting the alternating current voltage of said alternating current input to a node when said alternating current voltage is above a first predetermined value and for disconnecting said alternating current voltage from said node when said alternating current voltage is below said first predetermined value, and a second contact responsive to said second sensor for outputting said first direct current output to said second output when said direct current voltage is above a second predetermined value, for disconnecting said first direct current output from said second output when said direct current voltage is below said second predetermined value, and for electrically connecting said node to said second output when said direct current voltage is below said second predetermined value.