IEEE - The Institute of Electrical and Electronics Engineers@ Inc.
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IEEE 66-1969
Scope
This Guide presents geneal recommendations for determining@ by approximate methods from name plate data@ the short-circuit characteristics of direct-current motors and generators. The method is applicable to general-purpose general industrial mill motors and special-purpose direct-current machines. This includes constant-speed and adjustable-speed motors and machines with and without compound windings@ and with and without compensating windings. This Guide is intended to help those concerned with the transient characteristics of direct-current machines and direct-current systems and the effects of these transients on their operation. The calculated values of rate of rise and peak armature current will facilitate the proper selection of system components which will safety withstand the mechanical and thermal stresses during fault. When using nameplate data@ the approximate methods presented will yield results sufficiently accuate for estimates. Values computed by this method will be high@ in general@ thus on the safe side. Where no flashover exists@ a range of accuracy of -20 to +30 present can be attained. An exact and rigorous analysis is made difficult@ if not impossible@ by the variability and nonlinearity of the parameters involved in short-circuit calculations@ and is beyond the scope of this Guide. However@ those wishing to pursue a more exact approach are referred to [6]@ [9]@ [20]@ and [21] for methods of computation utilizing design and test data. A range of accuracy of -5 to +10 percent can be attained where no flashover exists. PURPOSE The purpose of this Guide is (a) to review the factors that affect the short-circuit characteristics of direct-current machinery. (b) to recommend methods for approximating the ate of rise and peak value of armature current from name plate data. (c) to discuss the causes of flashover and its effect on short-circuit current and effective armature circuit resistance.
IEEE 66-1969 history
1969IEEE 66-1969 Guide for Determination of SHORT-CIRCUIT CHARACTERISTICS OF DIRECT-CURRENT MACHINERY
1957IEEE 66-1957 Proposed Guide for Determination of SHORT-CIRCUIT CHARACTERISTICS OF DIRECT-CURRENT MACHINERY