Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 14 replies
  • Subscribers 33 subscribers
  • Views 2127 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

8 ft. Switch start fluorescent batten fitting.

Zoomup

I came across one of these yesterday. It has failed. I suspected the series capacitor had gone open circuit. The choke winding was continuous and the tube looked o.k. The fitting was removed and a new one fitted.

So, having forgotten the theory, how does the circuit work with an 8 ft. tube and a choke and series capacitor? What is the principle of operation?

 

Z.

  • 0

    Yes, but the older types of fluorescent tube that contained argon and were often but not always T12 would strike from line voltage without any high voltage pulse. Lamps up to 5 feet in length sometimes used a transformer start circuit.

    A choke was inserted in series with the supply, and a transformer with three windings was also used, one 220 volt winding and two windings each of 9 or 10 volts.

    The 220 volt winding was connected across the lamp and the two lower voltage windings connected one to each heater.

    Initialy, with a 240 volt supply, about 20 volts was dropped across the choke and about 220 volts applied to the starting transformer. This produced 9 or 10 volts on each heater and the lamp would strike almost instantly. Under running conditions the voltage across the lamp was about 110/120 volts and the starting transformer gave a few volts continually on each heater.

    Simple and reliable with no starter to fail. More expensive and less efficient though. Such a circuit would on a good day strike a lamp with one heater open circuit.

  • 0

    I used to have a 2 foot tube in my shed  ive still got the light but not the shed which would occasionally instant start it only ever did it a few times  i noticed a sort of blueish glow around the filaments when it started like this I found out later this damages the cathodes as there was no preheating  so glad it didn't do it often

  • Former Community Member
    0 Former Community Member

    If a lamp fails to strike, you can always get everybody in the room to wave their hands in the air.

     I still get clients falling for this old proverb Chris!

     Regards BOD

  • 0

    perspicacious: 
     

    If a lamp fails to strike, you can always get everybody in the room to wave their hands in the air.

     I still get clients falling for this old proverb Chris!

     Regards BOD

Community Rules & Guidelines