Search results
Results from the WOW.Com Content Network
An emergency switch in Japan. On railways, [1] an emergency stop is a full application of the brakes in order to bring a train to a stop as quickly as possible. [2] This occurs either by a manual emergency stop activation, such as a button being pushed on the train to start the emergency stop, or on some trains automatically, when the train has passed a red signal or the driver has failed to ...
SCRAM button at the Experimental Breeder Reactor I in Idaho. Sometimes the switch will have a flip cover to prevent inadvertent operation. A scram or SCRAM is an emergency shutdown of a nuclear reactor effected by immediately terminating the fission reaction.
Its function is distinct from that of pressure relief valves, which are passive devices opening if pressure reaches a value above the process safety trip, but still below the design pressure of the equipment. Relief valves complement the PSD. A process plant is typically divided into isolatable sections by emergency shutdown valves (ESDVs).
Safety relays must always be designed in such a way that, if wired correctly, neither a fault in the device nor an external fault caused by the sensor or actuator will lead to the loss of the safety function. [8] A normal relay uses a wire coil and the mechanical movement of the metal contacts to switch the load on and off.
PST is used to assist in determining that the safety function will operate on demand. PST is most often used on high integrity emergency shutdown valves (ESDVs) in applications where closing the valve will have a high cost burden yet proving the integrity of the valve is essential to maintaining a safe facility. In addition to ESDVs PST is also ...
A shutdown valve (also referred to as SDV or emergency shutdown valve, ESV, ESD, or ESDV; or safety shutoff valve) is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment.
The status and operation of both vigilance and dead man's switch may be recorded on the train's event recorder (commonly known as a black box). Modern locomotive practice is to incorporate the dead-man's and vigilance functions under the control of the alerter or the event recorder. [5]
The device numbers are enumerated in ANSI/IEEE Standard C37.2 Standard for Electrical Power System Device Function Numbers, Acronyms, and Contact Designations. Many of these devices protect electrical systems and individual system components from damage when an unwanted event occurs such as an electrical fault .