IEC 60644:2009 pdf free download

IEC 60644:2009 pdf free download Specification for high-voltage fuse-links for motor circuit applications
Scope
This standard applies primarily to fuse-links used with motors started direct-on-line onalternating current systems of 5o Hz and 60 Hz.
NOTE When motors are used with assisted starting this specification can also be applied but particular attentionshould be paid to the selection of the rated current of the fuse-link (see 8.1) and the manufacturer of the fuse-linkshould preferably be consulted.
Fuse-links according to this specification are intended to withstand normal service conditionsand motor starting pulses.They should comply with the requirements of lEC 60282-1.
The purpose of this standard is to standardize time-current characteristics, to formulate pulsewithstand requirements regarding testing and to give guidance regarding the selection of fuse-links intended to be used with motors.
2Normative 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 editionof the referenced document (including any amendments) applies.
IEC 60282-1:2005,High-voltage fuses – Part 1: Current-limiting fuses
3Fuse-link time-current characteristics
Compared to fuses typically used for distribution system protection，fuses for motor circuitprotection should have:
relatively high melting current (slow operation) in the 10 s region of the pre-arcing time-current characteristic to give maximum withstand against motor starting current;
relatively low melting current (fast operation) in the region below 0,1 s to give maximumshort-circuit protection to associated switching devices,cables and motors and theirterminal boxes.
Therefore pre-arcing time-current characteristics of fuse-links for motor circuit applicationsshall be within the following limits:
where
I n is the numerical value of the current rating, expressed in amperes, of the fuse-link;
4 K factor
Factor which defines an overload characteristic to which the fuse-link may be repeatedly subjected under specified motor starting conditions, and other specified motor-operating overloads, without deterioration.
For the purpose of this specification, the value of K is chosen at 1 0 s. Unless otherwise stated by the fuse-link manufacturer, it is valid from 5 s to 60 s, for a frequency of starts up to six per hour and for not more than two consecutive starts.
For conditions different from those specified above, for example where service conditions involve inching, plugging or more frequent starts, the manufacturer should be consulted. The overload characteristic is obtained by multiplying the current on the pre-arcing characteristic by K (less than unity).
5 Withstand requirements
The performance of a fuse-link for motor circuit applications is in general determined by the following criteria:
– to withstand without deterioration starting pulses in rapid succession due for example to abnormal conditions, such as those occurring during commissioning of the equipment;
– to withstand without deterioration a large number of motor starts in normal service conditions.
This standard therefore specifies two sequences of tests representative of these conditions: 1 00 cycles corresponding to abnormal service conditions; 2 000 cycles corresponding to normal service conditions. It is expected that a fuse-link which passes these tests will have a good behaviour during a satisfactory life duration.