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Current chopping

The magnitude of the TRV, which is the product of 2s X lc( c being the current chopped), can be determined with the help of curves shown in Figure 17.8. These... [Pg.563]

In the first case, it is easy to interrupt the circuit, which poses no problem of current chopping (premature tripping) before a current zero or a prolonged arc after a current zero for the following reasons ... [Pg.569]

I No current chopping An induction motor or a transformer should be operating at near full load, to possess a high p.f. and carrying a near full load current... [Pg.569]

By selecting the rating of the interrupting device as close to the full-load current of the system or machine as possible. An excessive rating than necessary may have tendency towards current chopping. [Pg.579]

Influence of frequency on the system 19/647 Viitual current chopping 19/648... [Pg.627]

The circuit lends to interrupt at a normal current zero and causes no current chopping. A BOCB is generally designed with two breaks per pole that help in restoring the dielectric strength promptly during an arc interruption. [Pg.633]

They may inherit current chopping tendencies at very low currents of 3-5 A, varying from one manufacturer to another and depending upon the contact material used. This is due to their extremely fast operation as a result of a high vacuum pressure of the order of 10 Torr (1.333 x 10 N/nr) or more (one Torr being the pressure equivalent to hold a column of mercury... [Pg.644]

High resistance-low kA alloy (low melting point) copper-chromium (CLR) w hich also has a good resistance to cold welding and a lower probability of current chopping, similar to in OCBs. Refer to curve 2 of Figure 17.8. [Pg.645]

Figure 19.27 Approximate representation of assumed voltage and current waveforms illustrating a current-chopping effect and its attenuation while interrupting a circuit having 0,3 p.f. Figure 19.27 Approximate representation of assumed voltage and current waveforms illustrating a current-chopping effect and its attenuation while interrupting a circuit having 0,3 p.f.
Time for 0.02 part of one-half of a cycle of a normal frequency wave of 50 Hz, during which current chopping occurs ... [Pg.648]

By the immediate first current zero it is assumed that the contacts have travelled sufficiently apart to achieve the required deionization and have built up adequate dielectric strength to withstand at least 0.95 V, . If the circuit does not interrupt at the immediate current zero at a which is so near to the point of chopping Vt , the interruption will take place only by the next current zero at point h and result in another 260 strikes by then. To study more accurate behaviour of an intenupter, with the number of restrikes and the formation of the actual transient voltage waveforms on current chopping, oscillograms similar to those during a short-circuit test may be obtained (Section 14.3.6). [Pg.648]

Ii is seen ihai ihe surge frequency during current chopping may rarely exceed 20 kHz and which, in the context of switching. surges, may be considered as low-frequency oscillations, easy to handle and interrupt. [Pg.648]

From the above we can deduce that at the instant of current chopping the arc extinguishes for a moment and... [Pg.648]

Figure 19.29 An approximate illustration of a virtual current chopping in Phase B as a consequence of restrike of arc in Phase / ... Figure 19.29 An approximate illustration of a virtual current chopping in Phase B as a consequence of restrike of arc in Phase / ...
No, because of force of air blast even at small currents which may develop the tendency to current chopping. On the other hand, il is possible that the breaker may fail to interrupt the sleep fronted TRVs... [Pg.652]

Generally not, because of extremely fast deionization. Il has the tendency to current chopping. However, in view of continuous development in thi.s field, il has now been possible to achieve a chopping current as low (Con/Jj... [Pg.652]

Current chopping phenomena of MV circuit breakers , IEEE Transactions, PAS -96, No. I (1977). [Pg.656]

The production of metal vapor upon arc interruption necessary to control current chopping and permit voltage recovery and... [Pg.213]

Fig, 11. Photoacoustic X-ray absorption spectrum and X-ray absorption spectrum for copper foil (5 pm thick). Photoacoustic signal is normalized by ion chamber current. Chopping frequency 10 Hz. Ring current 145-142 mA... [Pg.152]

Current chopping Sudden cessation of arc current at the time of arc extinction. [Pg.356]

See other pages where Current chopping is mentioned: [Pg.558]    [Pg.564]    [Pg.569]    [Pg.571]    [Pg.577]    [Pg.577]    [Pg.594]    [Pg.627]    [Pg.630]    [Pg.633]    [Pg.636]    [Pg.639]    [Pg.644]    [Pg.645]    [Pg.646]    [Pg.646]    [Pg.648]    [Pg.648]    [Pg.648]    [Pg.648]    [Pg.649]    [Pg.649]    [Pg.652]    [Pg.655]    [Pg.990]    [Pg.997]    [Pg.31]    [Pg.363]    [Pg.365]   


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