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A limit switch with a roller-lever operator; this is installed on a gate on a canal lock, and indicates the position of a gate to a control system A limit switch mounted on a moving part of a bridge In electrical engineering , a limit switch is a switch operated by the motion of a machine part or the presence of an object.
A Single-Pole, Single-Throw (SPST) mercury switch on millimetre graph paper, device length approximately 1.5 cm Another mercury switch design. A mercury switch is an electrical switch that opens and closes a circuit when a small amount of the liquid metal mercury connects metal electrodes to close the circuit.
These switches control which reed ranks are enabled (opened up) or disabled (closed off): some switches enable a single reed rank, others enable several simultaneous reed ranks. In general, the formula for the number of potential switch combinations is one less than 2 to the number of unique reed blocks that are within the accordion.
(from top) Single-pole reed switch, four-pole reed switch and single-pole reed relay. Scale in centimeters. A reed relay [i] is a type of relay that uses an electromagnet to control one or more reed switches. The contacts are of magnetic material and the electromagnet acts directly on them without requiring an armature to move them.
A reed switch has very low resistance when closed, typically as low as 0.05 ohms, whereas the Hall effect sensors can be in the hundreds of ohms. A reed switch requires only two wires whereas most solid-state devices require three wires. A reed switch can be said to require zero power to operate it.
A high-voltage disconnect switch used in an electrical substation. Such switches are used mostly to isolate circuits, and usually cannot break load current. High-voltage switches are available for the highest transmission voltages, up to 1 million volts. This switch is gang-operated so that all three phases are interrupted at the same time.
High-speed impact takes its toll on all reed valves, with metal valves suffering in fatigue. The physical inertia of reed valves means that they are not as entirely precise in action as rotary valves , a rotary valve engine may run better than a reed valve engine at a small rpm range but the reed valve engine often runs better over a wider rpm ...
A thermal switch (sometimes thermal reset or thermal cutout (TCO)) is a device which normally opens at a high temperature (often with a faint "plink" sound) and re-closes when the temperature drops. The thermal switch may be a bimetallic strip, often encased in a tubular glass bulb to protect it from dust or short circuit. Another common design ...