GB1296220A - - Google Patents

Abstract

1296220 Overload protective systems T MOORE 13 Dec 1969 60896/69 Heading H2K An overload-responsive arrangement has a first thermal switch to effect the operation of an indicator at a first excess current level and a second thermal switch to effect the operation of a further indicator and the interruption of the supply to a protected device, e.g. a motor, at a higher current level. In the arrangement shown, a green lamp 17 is lit when the motor is not overloaded. When the first current level is reached, a bimetallic element 22 in series with the motor closes contacts 24, 25 to light an amber lamp 16. When the higher current level is reached, bimetallic elements 26, 27 move apart to open contacts 30 and interrupt the current to the motor. A red lamp 15 connected across the elements 26, 27 is now lit with the result that the voltage across the motor is not sufficient to maintain the lamps 16, 17 lit. The arrangement may be disposed in a housing with a socket outlet and the housing may have plug pins so that it may be used as an adapter.