Fluorescent Tubes - Instant On Off Control

[Steve Adam]

I'm keen on the idea of using fluorescent tubes as part of a portable rig that I can use when I'm out gigging. The important thing is that they can come off and on instantly so that I can programme some fast moving dynamic effects.

 

This thread from a while back came tantalisingly close to what I was looking for. The thing that interests me the most is using transformers to preheat the tubes as I am hoping to use something like this to control them.

 

I only need the tubes to go off and on (not worried about dimming) and wondered if anyone is able to dig out or point me in the right direction of circuit details for this type of set-up?

[niclights]

Anytronics were showing some very nice ballasts for fluorescent control at Plasa this year. Instant on/off that was fast enough for strobing and incredibly smooth dimming (even if you don't want it!) It was not possible to do this from completely off however - they need to sit at approx 1%. There is a slight flicker when striking from zero. This is the best control I have seen for fluorescents. IIRC controller gave multiple outs, each of which could handle 15 tubes of any type.

[dbuckley]

Decades ago I did an installation which used ordinary dimmable ballasts and a Zero88 Micro 4 contoller, and the tubes came on and went off instantly. By "ordinary dimmable ballast" I mean the type that has two live terminals, one permanently on, the other goes to the dimmer source. The permanetly on live keeps the tube filaments permanenely on, so the tube strikes instantly. One warning; the dimmer has to be capable of operating into inductive loads.

 

I think fluoros used this way as an effect really look great, but you dont see it done much.

[BlueShift]

I second the anytronics stuff, they seem to have fluoro ballasts down!

[Steve Adam]

The only dimmable ballasts I have come across are the type where the dimming control is a 1-10V or DALI signal which isn't something I can control from MIDI without a chain of assorted converters which very quickly pushes the cost above what I can afford (this is more of a hobby than anything else at present). But do I gather from your post that it is possilbe to get ballasts with two sets of 220v inputs, one for preheating the tubes and the other to control the dimming? That's exactly what I am looking for but struggling to find.

 

The alternative is to adapt the electronics of a standard fitting and use low voltage transformers to keep the tubes warm - I know it's possible to do it this way (and I daresay cheaper) but I don't want to attempt this without some detailed guidance as to how to do it properly and safely (I'm not an electrician by trade).

 

The Anytronics stuff looks great and I will contact them - but I suspect gear that good will come at a price.

[musht]

Don Klipstein`s fluro guide:

 

http://members.misty.com/don/f-dim.html

[Tomo]

It sounds like you are after "two-wire dimmable ballasts".

 

You provide these with a switched mains voltage supply, and a forward-phase dimmed supply - from a standard SCR dimmer.

 

To turn it completely off you kill the switched supply, and to dim you turn on the switched supply, then dim the standard dimmed supply.

 

Clever stuff within the ballast uses the firing point of the dimmed supply to properly dim the florry.

 

This is the cheapest way to do reasonably well-dimmed florries - you generally don't get anything below around 20-40% though, depending on tubes etc.

[dbuckley]

I wonder if the traditional dimmable ballast has gone the way of the dinosaur.

 

A dig in the filing cabinet produced the data sheet for the ballasts I used, made by Transtar, model ASCR. However, a quick dig on the Transtar website shows they no longer have anything similar. Maybe you could call them and ask?

[Steve Adam]

I did speak to Transtar before posting here, as I saw their name mentioned elsewhere in relation to this type of thing, and you're right, they don't do that sort of stuff anymore. You do still get ballasts with 'preheating' but not in the sense that there is a permenant AC connection thus facilitating truly instant off/on. This doesn't seem to be something that manufacturers aim for these days, although I can understand that since I imagine the vast majority of fluorescent users aren't bothered about a 0.5 - 1 second delay.

 

Based on what seems to be available these days I'm thinking my options are going to be limited to:

 

a) Using modern HF dimmable ballasts and accepting that I'm going to have to get involved with converting to DALI protocols or similar

 

b) trying out the type of circuit shown in Don Klipstein's guide but as someone mentioned earlier, there is still the issue of whether or not the MIDI controlled dimming pack I have in mind would even be suitable for controlling this in the first place and it looks like tube life is a problem as well if you don't know exactly what you're doing.

[back_ache]

Just simply get readily available 1-10v dimmable ballasts and feed it from a DMX demux, this will take the tube from 100% to as dim as it can go (but not dark or off), if you want it off you will need to feed it mains from a DMX relay or make some kind of opto-isolated relay that runs off the same 0-10v line so that at 0% the juice gets cut.

[raar]

Have a look at http://www.se-ag.ch search for VIP90 till now the best solution I know off, only downside the website is in german.

[dbuckley]

Raar, which exact model of ballast enhancers (cos you need a normal mag ballast as well) did you use with which tubes, and where did you order these things from?

 

These do seem to be well regarded, RJ uses them for it's fluoro fittings, amongst others...

[tonythetechie]

I only need the tubes to go off and on (not worried about dimming) and wondered if anyone is able to dig out or point me in the right direction of circuit details for this type of set-up?

 

Hi Steve

 

Hope this is helpful, I created some light boxes earlier this year and didn't want the boxes to dim but come on and off on demand.

 

After searching the internet and investigating I found these High Frequency Ballasts to be the way to go.

 

Hope this is of some help to you

 

Tony

[dbuckley]

I suppose I should have added a THREAD NECROMANCY ALERT!!!

[Jivemaster]

Current d0m3stic compact fluorescents are close to instant but rise to about 50% brightness then warm up to 100% over a minute if struck from cold (sub 10C) Once struck they restrike to full brightness.