Author Topic: some experiments  (Read 2447 times)
hannahs lights
Member
*****
Offline

Gender: Female
View Posts
View Gallery

Re: some experiments « Reply #15 on: May 13, 2016, 05:13:08 PM » Author: hannahs lights
I noticed that if I rubbed the tube with my hand it seemed to assist the starting not sure if it was coincidence or not il do more tests to try to decide. I have seen a scope connected to a streetlight ballast show very high voltage spikes more or less at zero cross point I think this is what you mean is happening with a flourescents inductive ballast its a big voltage kick but I can't see it on my own setup but I know my scope is a bit old and not up to the job.
Logged
Medved
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: some experiments « Reply #16 on: May 14, 2016, 02:49:26 AM » Author: Medved
I noticed that if I rubbed the tube with my hand it seemed to assist the starting not sure if it was coincidence or not il do more tests to try to decide.

You have made there an external electrode assisting the start. In fact this is, what exactly is the purpose of "grounded reflector closer than something" requirements on many ballasts - they need such external electrode as well, then the most practical way is to utilize the metal reflector.


I have seen a scope connected to a streetlight ballast show very high voltage spikes more or less at zero cross point I think this is what you mean is happening with a flourescents inductive ballast its a big voltage kick but I can't see it on my own setup but I know my scope is a bit old and not up to the job.

These spikes are not that fast, we are talking about time scale of 10's us or so, so even a prehistoric vacuum tube 1MHz oscilloscope should be capable to capture that.
It is more due to the fact, then the high pressure makes the arc faster to respond (everything is denser, so it takes less time for a ion to meet some free electron) than with the low pressure discharges. Mainly the HPS and MH's are very bad at this (with MV's, it is the probe presence, what makes the arc way easier to reignite - as it is with a short gap, it gets easier ionized, then priming the main discharge path)...
Logged

No more selfballasted c***

hannahs lights
Member
*****
Offline

Gender: Female
View Posts
View Gallery

Re: some experiments « Reply #17 on: May 14, 2016, 01:11:22 PM » Author: hannahs lights
Hey Medved I forgot to mention the current transformer I'm using that mum gave me is actually from a wattmeter designed to encourage consumers to reduce there power usage the meter itself was woefully inaccurate which is why I got the transformer to use with my ancient scope  I will try some more tests with the lamps I got the circular one has no earth connection so assisted starting might help it with a resistive ballast  il let you know
Logged
Print 
© 2005-2022 Lighting-Gallery.net | SMF 2.0.19 | SMF © 2021, Simple Machines | Terms and Policies