N.E.M.A. Handbook for Power Switchboard and Switching EquipmentNational electrical manufacturers association, 1927 - 119 páginas |
Palavras e frases frequentes
A. I. E. E. Rule Adopted Standard alternating current ambient temperature apparatus arranged automatic switching equipment bars bolts bus supports busbar buses cable Calculation CHIG closing conductors connections constructed Contactor cuit breaker current transformers current-carrying device dielectric strength direct current disconnecting switches electrically operated electromagnetic force enclosed enclosures factor floor functions furnished fuses fusible cutouts GAN UNIV ground guarded indicating inspection installed instruments insulation interrupting capacity isolated by elevation laminations lamps lateral stress load located longitudinal stress manufacturer material maximum means ment meters motor mounted natural frequencies necessary oil circuit breakers operating mechanism phase pipe pole power switchboards prevent proper protection Purchaser qualified persons Reactance Recommended Practice Relay resistors rheostats rods short circuits shunt space span specified structure support stress Synchronizing tion trip coil truck type UNIV MIC UNIV SITY UNIV UNIV voltage ratings volts wiring
Passagens conhecidas
Página 38 - A totally enclosed machine so constructed that a stream of water from a hose (not less than 1...
Página 52 - Undervoltage or lowvoltage protection is the effect of a device operative on the reduction or failure of voltage to cause and maintain the interruption of power in the main circuit.
Página 7 - ... because of the large number of variables involved and because of the wide range of the constants for the customary structures.
Página 3 - Aggregates shall not contain strong alkali or organic material which gives a color darker than the standard color when tested in accordance with the "Standard Method of Test for Organic Impurities in Sands for Concrete" ( Serial Designation : C 40-27 ) of the American Society for Testing Materials.
Página 95 - ... not exceeding 400 volts to ground or 750 volts between any two points of the circuit, and the transmitted power of which does not exceed 150 watts. When operating at less than 150 volts no limit is placed on the capacity of the system.
Página 100 - Handles or levers of circuit breakers, and similar parts which may move suddenly in such a way that persons in the vicinity are liable to be injured by being struck by them, shall be guarded or isolated.
Página 42 - Switchboard: A large single panel, frame, or assembly of panels, on which are mounted, on the face or back or both, switches, overcurrent and other protective devices, buses and usually instruments. Switchboards are generally accessible from the rear as well as from the front and are not intended to be installed in cabinets.
Página 96 - Guarded. Covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of approach to a point of danger or contact by persons or objects.
Página 71 - Relay or Switch is a device which functions merely to place and hold an equipment out of operation. (6) Starting Circuit Breaker or Contactor is a device which connects machine to source of starting voltage. (The starting breaker connecting the machine to starting voltage should always be No. 6. If a compensator is present the breaker energizing the compensator is No. 6 C. If one breaker has sufficient number of poles to perform both functions, it should be designated as No. 6. In Korndorffer starting...
Página 95 - ... designed to be placed in a cabinet or cutout box placed in or against a wall or partition and accessible only from the front.