HPS & MH igniter question.

[dacflyer]

i have been working with street lights a long time, i do know there is a difference between
HPS & MH igniters, but what differences i do not know..
whats inside of these things that makes them tick ?
and is there a way to test them without having to wire them into a fixture?
google did not help much here today

[dacflyer]

no ideas from anyone yet...

[ltx71cm]

From a very quick Google skim the ballasts are compatible with one exception. The exception is the igniter used in HPS fixtures. I also read that ballasts exist that can be used with both light types.

[dacflyer]

yes that i know.. but i need to know what the difference is in the 2 different types of ignitors.
there are 2 different types, and a MH ignitor will not work with a HPS ballast

[ltx71cm]

From what I read the MH bulbs don't use an igniter, just the ballast. The combo ballasts switch the igniter out of circuit when using a MH lamp.

[haklesup]

In general the way I understand ballast is that they provide one higher voltage at open load (as when the lamp is not lit) which gets the plasma lit, then it falls to a lower loaded voltage as current begins to flow through the plasma or arc. An ignitor is a secondary tap or winding which applies another even higher voltage at no or very low current to a key spot in the lamp assembly to jump start the plasma or arc. This voltage also collapses when current begins to flow through the lamp.

To ferret out your question, I would look for the specs of the bulb and what it needs to glow and start. a ballast would simply satisfy those requirements.

[dacflyer]

the reason why i was asking is,, i had to work on some lights, and a 400HPS unit was out,, i determined that it needed an ignitor, well i just happen to have a MH ignitor rated for
50-400 watts. thinking it would work, it didn't , it wired up the same way as a HPS ignitor.
so i had to go get the right HPS ignitor, it too was rated for 50-400 watts, but it said for HPS use.
i put it in, and everything worked. so thats why i was trying to find out what the difference was electrically inside the ignitor. i do know a 400 watt ballast will work with HPS or MH.
thats not my delima..