Generators continuous duty

Maximum continuous speed for generator drive duty is synchronous speed. 

When generators are specified, it should be realized that both mechanical and electrical requirements differ between units which will be used for standby service and units which will be operated continuously. Typically, standby units have less copper in their windings than continuous duty units, causing standby units to reach higher temperatures if operated continuously, and thus reducing life. Standby units, as classified by most manufacturers, are not to be confused with units which are alternated weekly (or on some other regular basis), but which are operated continuously when they are on line. This operating mode should be considered continuous duty. ... 

Internal Regenerator Bed Colls. Internal cods generate high overall heat-transfer coefficients [550 W / (m -K)] and typically produce saturated steam up to 4.6 MPa (667 psi). Lower heat fluxes are attained when producing superheated steam. The tube banks are normally arranged horizontally in rows of three or four, but because of their location in a continuously active bubbling or turbulent bed, they offer limited duty flexibdity with no shutdown or start-up potential. 

External Dilute-Phase Upflow Cooler. The external ddute-phase upflow design (68) offers some control in the range of heat removal duties but generates relatively low heat-transfer coefficients [60—170 W/(m K)]- This design substantially increases the surface area requirement and thereby reduces the ultimate duty that can be achieved from a single bundle. In addition, poor mechanical rehabdity has been continuously experienced because of excessive erosion at the lower tube sheets as a result of the high catalyst fluxes and gas velocities imposed. 

Another significant challenge remains in further increasing the efficiency with which sample species are utilized through increased ion throughput and duty factor. Currently many of the ions generated by continuous ionization sources are lost because of the pulsed nature of the instrument. Realization of higher duty factor and the unit transmission efficiency of which TOF-MS is capable could propel the TOF-MS into a sensitivity realm well beyond that of current mass analyzers. 

In chemistry also, we are now conscious of the continuity of man s intellectual effort no longer does the current generation view the work of its forerunners with a disdainful lack of appreciation andfar from claiming infallibility, each successive age recognizes the duty of developing its heritage from the past. 

ESI is a continuous process. While the potential is applied between the capillary tip and the entrance to the mass spectrometer, ions are generated in a constant stream. However, the nature of the FT-ICR experiment requires discrete packets of ions that are first trapped in the ICR cell then excited and detected. To maximize the duty cycle, ions are accumulated externally before being transferred to the ICR ceU [13]. Accumulation of ions can be achieved by use of storage hexapoles, octapoles, or ion traps. 

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