Miniature fault indicator

Abstract

A rugged, miniature, waterproof and lightweight magnetic latching indicator with an auxiliary switch. The indicator includes a solenoid, an elongated plunger mounted in the solenoid, the plunger supporting a first permanent magnet with the magnet being surrounded by specially dimensioned non-magnetic spacers. The plunger and solenoid are packaged in a non-magnetic housing with a solenoid locator, a top cap and a bottom cap maintaining the indicator in a compact waterproof package. An indicator button is mounted to the plunger and a reed switch biasing spring and second permanent magnet are located between the bottom cap and the solenoid. The plunger moves from a retracted latching position to an extended position. In the retracted position, the indicator button is retracted and not readily visible and the second permanent magnet maintains the reed switch in a closed position. In the extended position, the indicator button is readily visible and the second permanent magnet is spaced from the reed switch causing the reed switch and any external circuitry connected in series with the reed switch to open.