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AC contactor for pump application. A contactor is an electrically controlled switch used for switching an electrical power circuit. [1] A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24-volt coil electromagnet controlling a 230-volt motor switch.
Most national laboratories maintained staffs of local researchers as well as allowing for visiting researchers to use their equipment, though priority to local or visiting researchers often varied from lab to lab. With their centralization of resources (both monetary and intellectual), the national labs serve as an exemplar for Big Science.
When a pair of contacts touch, they can pass an electrical current with a certain contact resistance, dependent on surface structure, surface chemistry and contact time; [2] when the pair is separated by an insulating gap, then the pair does not pass a current.
University affiliated laboratories have been conducting research and development for the United States Navy since 1942, beginning with the creation of the Applied Physics Lab at Johns Hopkins. The most recent UARC, created in 2023, is the Research Institute for Tactical Autonomy , led by Howard University , which is performing research for the ...
Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the Los Alamos and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence "big science" approach, tackling challenging ...
They are used as high-current switches or contactors, where contact erosion from constant cycling would be a problem for conventional relay contacts. Owing to environmental considerations about the toxicity of mercury, mercury relays are mostly obsolete, though modern encapsulated units still have applications.
A magnetic starter has a contactor and an overload relay, which will open the control voltage to the starter coil if it detects an overload on a motor. [1] [2] The overload relay opens a set of contacts that are wired in series with the supply to the contactor feeding the motor.
Centrifugal contactors are typical referred to by the diameter of their rotor. Thus, a 5-inch centrifugal contactor is one having a 5-inch diameter rotor. Annular centrifugal contactors are relatively low revolutions-per-minute (rpm), moderate gravity enhancing (100–2000 G) machines, and can therefore be powered by a direct drive, variable ...