GB/T 12668.6-2011 Adjustable speed electrical power drive systems—Part 6:Guide for determination of types of load duty and corresponding current ratings
1.1 Scope and Object
This part provides alternative methods for specifying ratings for adjustable speed electrical power drive systems (PDS) and in particular their basic drive modules (BDM).
It is not intended to cover adjustable speed drives for traction purposes.
General rules for rating specification for low voltage adjustable speed d.c. power drive systems are contained in IEC 61800-1, and for low voltage adjustable frequency a.c. power drive systems in IEC 61800-2.
1.2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60146-1-1 Semiconductor Convertors - General Requirements and Line Commutated Convertors - Part 1-1: Specifications of Basic Requirements
IEC 61800-1 Adjustable Speed Electrical Power Dive Systems - Part 1: General Requirements - Rating Specifications for Low Voltage Adjustable Speed D.C. Power Drive Systems
IEC 61800-2 Adjustable Speed Electrical Power Dive Systems - Part 2: General Requirements - Rating Specifications for Low Voltage Adjustable Frequency A.C. Power Drive Systems
2 Terms, Definitions and Symbols
2.1 Terms and Definitions
For the purpose of this part the definitions given in IEC 61800-1, IEC 61800-2 and IEC 60146-1-1 as well as the following apply.
2.1.1
equilibrium temperature
steady-state temperature reached by a component of a converter under specified conditions of load and cooling
Note: Steady-state temperatures are in general different for different components. The times necessary to establish the steady state are also different and proportional to thermal time constants.
2.1.2
current-time load chart
record of load current with respect to time
2.1.3
uniform load duty
duty for which a converter equipment carries a current of fixed value for an interval sufficiently long for the components of the converter to reach equilibrium temperatures corresponding to the said value of current. Figure 1 illustrates this type of load duty (see Table 1 for symbols)
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