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This standard applies to all low-voltage power-circuit breakers that are intended for use in field circuits of apparatus such as generators, motors, synchronous condensers, or exciters and embodying contacts for establishing field discharge circuits. In performing their function of interrupting field circuits of rotating electric machinery, field discharge circuit breakers are subject to the following conditions not met within the interruption of ordinary direct-current power circuits. In… read more alternating-current machine field circuits, in addition to the problems usually encountered in switching highly inductive directcurrent circuits, there is superimposed upon the voltage generated by the exciter, a voltage induced in the field windings by the transient current in the machine armature under alternating-current short-circuit conditions. These result in large pulsating currents in the field circuit as illustrated in Fig .Due to the large amount of magnetic energy stored in the machine field circuit, the interruption of the circuit results in an unusually high transient voltage under alternating-current short-circuit conditions, unless special means are provided for dissipating the energy.A discharge resistor must be connected across the terminals of the machine field by the discharge contacts of the circuit breaker just prior to disconnecting the field from its excitation source in order to provide for dissipation of the stored energy of the machine field and to minimize the transient voltage. The voltage across the field discharge circuit breaker main contacts following interruption of the excitation source current is illustrated in Fig .In addition to the above conditions, there is the usual direct-current short-circuit condition wherein the field circuit may become short-circuited. To cope with these unique conditions, this standard for field discharge breakers has been developed to establish the rating structure and test requirements not encountered in other ANSI Standards which apply to other low-voltage circuit breakers. The dielectric test values given in Table 7A, ANSI C37.16-1979 , Preferred Ratings, Related Requirements, and Application Recommendations for Low-Voltage Power Circuit Breakers and AC Power Circuit Protectors, reflect the change in dielectric test requirements in ANSI C50.13-1977 Requirements for Cylindrical Rotor Synchronous Generators. read less

定价： 110元 / 折扣价： 94 元

Since rotating electrical machines convert mechanical energy to electrical energy, or electrical energy to mechanical energy, base values for each kind of energy appear desirable in formulating a per-unit system. However, the relationship between these energies involves power factor and efficiency, which are not fundamental quantities and which vary considerably between different designs. Traditionally, designers of generators considered rated apparent output power as base power, and designers… read more of synchronous motors considered rated apparent input power as base power. Designers of synchronous motors used rated apparent input power as the base even though it was necessary to estimate efficiency. This permitted the use of the same design equations for both synchronous generators and synchronous motors. Designers of induction motors generally have used rated output power as base apparent power, eliminating assumptions of power factor and efficiency. This was particularly desirable when working with small machines or machines with many poles, where accurate estimates of power factor and efficiency were difficult to make. However, some induction machines are used as induction generators, so that the definitions of input power and output power depend on the mode of operation. read less

定价： 53元 / 折扣价： 46 元

This guide covers the application of surge voltage protective equipment to AC rotating machines rated 1000 volts and greater. The guide does not cover motors applied in solid-state switched adjustable speed drives. Part 1 covers the insulation surge withstand strength of motors and generators with windings having form-wound multi-turn coils and the application of surge protection to form-wound multi-turn coil motors. Part 2 will cover application of surge protection to generators with form-… read more wound multi-turn coils, plus insulation surge withstand strength and surge protection of single-turn coil generators and motors. read less

定价： 110元 / 折扣价： 94 元

This insulation maintenance guide is applicable to industrial air-cooled rotating electric machines rated from 5 hp to 10 000 hp. The procedures detailed herein may also be useful for other types of machines.

定价： 146元 / 折扣价： 125 元

This procedure is intended for form-wound bars/coils for rotating machines rated 10 kV or more at 50 Hz or 60 Hz that are subjected to many transitions from no-load to full-load current during normal operations, and where rapid load variations are typical. Only the thermal cyclic degradation within the groundwall insulation and/or the conductor package and delamination of the groundwall insulation from the conductor are addressed by this test. Examples of machine types that typically exhibit… read more rapid load transitions include: -- Combustion turbine generators -- Pumped storage or peaking duty hydrogenerators -- Synchronous condensers -- Cyclic duty water pump motors Various pass/fail criteria are presented, and the ones that apply in a specific circumstance must be agreed between the user and the manufacturer prior to commencement of testing. Whether a particular bar or coil has passed or failed is best determined by comparing the test results from a number of stator bars or coils. read less

定价： 84元 / 折扣价： 72 元

This recommended practice is limited to auxiliary devices associated with rotating electrical machines operating in Division 2 or Zone 2 areas, classified as Class I under the practice of ANSI/NFPA 70 or Zone 2 areas classified under the practice of IEC/CENELEC EN60079-10:1996.

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This recommended practice is limited to auxiliary devices associated with rotating electrical machines operating in Class I, Division 2 or Zone 2 areas or Class II, Division 2 areas or Zone 22 areas under the practice of NFPA 70, National Electrical Code® (NEC®) and CSA C22.1, Canadian Electric Code (CE Code).6 This recommended practice is not an attempt to rewrite or otherwise supersede applicable sections or clauses of these noted documents or any other codes or ordinances. Rather, it is… read more intended to serve as a supplement to existing codes that in this area may not be sufficiently specific to serve as a guide to good engineering practice. read less

定价： 56元 / 折扣价： 48 元

This recommended practice is limited to auxiliary devices associated with rotating electrical machines operating in Class I Division 2 and Zone 2 or Class II Division 2 and Zone 22 areas, as classified under the practice of the National Fire Protections Association (NFPA) standard NFPA 70, National Electrical Code(R) (NEC(R)) and the Canadian Standards Association (CSA) standard CSA C22.1, Canadian Electrical Code (CE Code). This recommended practice is not an attempt to rewrite or otherwise… read more supersede applicable sections or clauses of these noted documents or any other codes or ordinances. Rather, it is intended to serve as a supplement to existing codes that in this area may not be sufficiently specific to serve as a guide to good engineering practice. read less

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