Fusehead series firing

The curves of Fig. 10.7 apply only to fuseheads made to the same specification. If fuseheads are made with different bridgewires or different flashing dips, the corresponding curves could be completely different and there may be no point at which the minimum lag time of one type of detonator exceeds the maximum excitation time of the other. Under these conditions series firing would not be practicable and it follows that it is not feasible to use different types of detonators in a single series firing circuit. 

It was found that for the charcoal based squib, the transfer time was almost double the initiation dme. This large transfer time obviously takes care of the variations in the excitation timings due to different factors in the manufacture of squibs. This ensures continuous flow of current thru all the squibs connected in series until, the time the most sensitive squib breaks the circuit. In the case of LMNR and LDNOC fuseheads the transfer time was found to be quite low and the total time of some of the fuseheads was less than or equal to the excitation times of some others in the same group. Such squibs when connected in series caused failures in r.eries firing. As a confirmation to this theory, a retardant was introduced in the LMNR fuse-heads to increase the transfer lime, and no misfires were noted... 

SERIES RING A method of firing fireworks electrically by connecting wirebridge fusehead igniters in series, i.e. one after the other, so that the current flows through each in turn. 

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