need to determine the strike voltage of a fluoro tube

[ade_p]

Hello everyone I am Ade i know you guys get asked for help a lot so hopefull you can help me

My company have given me a small project basically to find out what voltage a 58W 110v fluorescent fitting will strike at. So how can i go about this and what can i make to do this.

My initial thoughts were to get either 2 variable resistors (or one duel variable resitor if they exist) one for L1 and one for L2 connecting in a voltage indicator on the 110v steady side so i can visably see that i have 110v constant and on the other side of the resistors another voltage indicaticator so that as i reduce the voltage then i can see a change and see what voltage i go down to before the fitting fails.

I am not sure what variable resitors i need or even if this is the correct way of doing this. Any advice or suggestions would be greatly received

Thank you
Ade

 

[Bluejets]

Better to work it out in theory.
Do a search on google re-inductance.
Any tests would at the very least require a scope.
Many dangers associated with what you are proposing.

 

[Colin Mitchell]

It ranges from something over 300v to about 750v, depending on if you are heating the ends. And it depends on how much "kick" you have in the voltage and how fast you want the tune to "fire."
It also depends on the pressure of the gas as there is a difference between fluoro and CFL.

 

[Harald Kapp]

Welcome to our forum.

58W at 110V are approx. 0.5A. You will not find easily resistors (even less variable ones) that can handle this current while dropping sufficient voltage as this means that in the worst case they may have to dissipate as much as 58W of power (assuming the lamp is replaced by a short circuit).

I suggest using a variable transformer, e.g. an autotransformer that is designed to deliver at least 60W to a load. You can then adjust the voltage to the lamp by setting the transformer accordingly.
To test the fluorescent lamp, you will also need a switch in series with the lamp. You will have to turn the lamp on and off for each setting of the transformer, as the lamp may not turn on at a certain voltage (lower than 110V of course), but may happily stay lit once it has been turned on at a higher voltage. Therefore reducing the voltage while the lamp is lit will probably not give you the expected results.

As always when dealing with mains voltages every possibly safety measure has to be observed as this

 

[Colin Mitchell]

"I suggest using a variable transformer, e.g. an autotransformer that is designed to deliver at least 60W to a load. You can then adjust the voltage to the lamp by setting the transformer accordingly."

This not what I considered the request to be.

 

[ade_p]

Thank you all for your comments.

How about a rheostat as this has been suggested to me but I'm not sure where to get one or if I can make one

Ade

 

[Colin Mitchell]

You must make yourself clear.
Are you talking about lowest line voltage or lowest strike voltage???????

 

[ade_p]

Lowest line voltage

Thank you all