Short-time current

Rated short-time current rating or fault level of a system (breaking current for an interrupting device) Duration of fault... 

Rated short-time current rating or fault level of a system... 

The short-time current, (I or 3 seconds), of the system to which this machine would be feeding is defined by /, ... 

Prospective short-circuit or short-time current Asc kA(r.m.s.) (symmetrical breaking current) Factor of asymmetry to obtain the peak short circuit or making current Co s (p... 

Both ratings, thermal and short-time, will define the cross-sectional area of the current-carrying components. The more severe of the two will then prevail. In the following text we explain the procedure to assign the short-time current rating to equipment, a device or a component. 

Figure 14.5 Determining the average r.m.s. value of the short-time current 4c from the oscillogram obtained during a short-circuit test...

Rated short-time current Rated primary current... 

Similarly, for a protection CT from Table 15.11 choose an accuracy class of I OPS with a VA burden of 5 for a second short-time current. If this does not meet the need, the protection CT may also have to be selected with a higher-rated primary current. 

Rated short-time current rating this is the same as for the system to which it is connected, and as assigned to the associated switchgear (Section 13.4.1(5)). The effects of a short-circuit on an electrical system are discussed below. 

In an isolated phase bus (IPB) system, the ground bus must be capable of carrying the same short-time current as for the main conductors for 2 seconds, for both disccrntinuous and continuous grounding systems. 

The cable must be selected on the basis of full-load current rating, voltage drop on both running and start-up, and short-time current rating. 

Fig. 4.28. The use of an electronic pulse generator to send an extremely short time current pulse through an electrochemical system so that there is dissolution at one electrode during the pulse.

Thus, the most suitable route for obtaining information on the adsorption/desorption kinetics is from the short-time transient behavior. Under these conditions, surface diffusion effects are negligible and the short-time current response depends only on Ka, Kd, and A for a given tip/substrate separation. Provided that an independent measurement of A can be made, an absolute assignment of the interfacial kinetics is possible. Furthermore, analysis of the long-time current allows the importance, and magnitude, of surface diffusion to be determined. 

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