Film-Tech Forum ARCHIVE: Cinemecanica Zenith3000 ignitor problems

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Posted by Gordon McLeod (Member # 33) on 08-02-2005, 12:10 PM:

i have been plagued with some issues with 5 zenith3000 ignitors that are not striking reliably
The auto strike relay pulls in
The highvoltage transformer generates output but there is no spark in the sparkgap (at various gap settings s well)
But put in a brand new lamp and the sparkgap fires (I can't figure out how that happens since the spark gap is on the input side of the teslacoil
Some of the sparkgaps have rounded points others have the sharp points some are 3 electrode some are 2 electrode and it makes no difference (the output of the HV transformer is in excess o 10KV as well o I have ruled out the HV transformer)
The only intereting note is that the spark gaps are coated with a white powder which i gather is acting like an insulator or if you clean it out it will work again for a week but the issue with the lamp influencing the spark gap I cant igure out
Anyone else ever encounter this

Posted by Rick Long Jr (Member # 541) on 08-03-2005, 08:56 PM:

I assume these are DX-5 igniters? Ive seen this before as well. Ive wondered that the white powder might be conductive rather than insulating,(kinda like creosote created by a fire is flammable) and when the bulb is new, the tungsten conducts well enough to fire a spark even if the tesla coil isnt getting zapped with all the available voltage. I could be way off base, but perhaps there's enough leakage through the powder to fire a new bulb?

I do know that Cinemeccanica had a kit that put two of the 1000pf 20Kv capacitors in parallel. I have had success adapting this to DX-5's before. It definitely helps.

As to the points in the spark gap, someone whose experience way surpasses mine once said that spark gaps with rounded points will fire more consistently, as there is a wider flame front. (The tesla coils at the Ontario Science centre have round electrodes. Poor analogy I know.)

I've found it interesting how different manufacturers use different spark gap designs. Cinemeccanica with the 3 pin pointed type; Xebex with the old stacked discs; Strong (39000) with a wider gap and small flat points. New Kinoton igniters have a similar spark gap to Cinemeccanica's except they wind the middle electrode in so it's completely between the outer two's points.