Phase-failure detectors responsive to unequal bending of bi-metal members
AssigneeBritish Nuclear Fuels plc
InventorJohn Barnes
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Abstract
Circuit breakers can be used to replace fuses in plant comprising centrifuge machines driven by small three-phase electric motors. The circuit breakers incorporate three bi-metal strips which bend due to the heat produced by current flow. Loss of current in one phase results in unequal bending of these trips. In one arrangement, a light-emitting diode 5 fitted to a first strip 2 produced light to pass through an aperture 8 in a plate 7 on the second strip 3 to fall on a photo-sensitive detector 6 on the third strip 4. Any unequal bending causes the light to be cut-off and the resulting signal can be used to trip the circuit breaker. In some cases the strips are the strips in the circuit breaker.
Claims3
A phase-failure detector comprising three bi-metal strips, and means mounted on the strips for detecting unequal bending in the strips arising from loss of current in a phase and arranged to provide a signal, in which the detecting means comprises a light source and a light detector respectively mounted on two of the strips, and an apertured plate between the source and the detector and mounted on the third strip.
Dependencies are inferred from the claim text.