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Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Series 'C' Magneto
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<blockquote data-quote="Magnetoman" data-source="post: 156669" data-attributes="member: 2806"><p>Although just about anything would be possible, basically the answer is 'no'. Also, this is a case where 'more' wouldn't necessarily be 'better'.</p><p></p><p>SmFeCo magnets have greater field strength so would induce greater current in the armature than with the internal Alnico magnet. But, without experiments to test the result, it's not clear the fine wire in the armature would survive the higher current. Even if it did, and even with a proper condenser, the points would erode faster. Further, a Lucas manual says the 300 rpm is the lower limit of kickstarting speed, and a properly remagnetized magneto will provide sufficient spark even lower than that. If your knee can't handle supplying 300 rpm, would you be willing to see if it survived the, say, 250 rpm a higher strength magnet might provide?</p><p></p><p>If I were to design a magneto from scratch I would do so using a SmFeCo magnet. But, I wouldn't retrofit a Lucas KVF with one. It would be easy to attach SmFeCo magnets to the outside of a KVF body, but it would be a mistake to do so for the reasons given in the previous paragraph. As a note for anyone tempted to try, a SmFeCo magnet has enough strength to significantly demagnetize a KVF when attached to the "wrong" magnetic pole, but it doesn't have enough strength to sufficiently remagnetize it afterwards when attached to the "right" one. You've been warned.</p><p></p><p>p.s. somewhere in one of the Appendices to the magneto thread on Britbike I have photographs of a magneto housing that I cut open, which lets you see where the Alnico magnet is located.</p></blockquote><p></p>
[QUOTE="Magnetoman, post: 156669, member: 2806"] Although just about anything would be possible, basically the answer is 'no'. Also, this is a case where 'more' wouldn't necessarily be 'better'. SmFeCo magnets have greater field strength so would induce greater current in the armature than with the internal Alnico magnet. But, without experiments to test the result, it's not clear the fine wire in the armature would survive the higher current. Even if it did, and even with a proper condenser, the points would erode faster. Further, a Lucas manual says the 300 rpm is the lower limit of kickstarting speed, and a properly remagnetized magneto will provide sufficient spark even lower than that. If your knee can't handle supplying 300 rpm, would you be willing to see if it survived the, say, 250 rpm a higher strength magnet might provide? If I were to design a magneto from scratch I would do so using a SmFeCo magnet. But, I wouldn't retrofit a Lucas KVF with one. It would be easy to attach SmFeCo magnets to the outside of a KVF body, but it would be a mistake to do so for the reasons given in the previous paragraph. As a note for anyone tempted to try, a SmFeCo magnet has enough strength to significantly demagnetize a KVF when attached to the "wrong" magnetic pole, but it doesn't have enough strength to sufficiently remagnetize it afterwards when attached to the "right" one. You've been warned. p.s. somewhere in one of the Appendices to the magneto thread on Britbike I have photographs of a magneto housing that I cut open, which lets you see where the Alnico magnet is located. [/QUOTE]
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Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Series 'C' Magneto
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