OLD FLUORESCENT FIXTURES

Status
Not open for further replies.

domnic

Senior Member
Occupation
Electrical Contractor
In old fluorescent fixtures that used a starter how did they work ( the starter) ?
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
In old fluorescent fixtures that used a starter how did they work ( the starter) ?
Short over-simplified version, the "starter" was a capacitor (condenser) that provided a voltage boost to start the excitation of the plasma in the lamps. Once started, it was easier to keep it excited with the ballast output, so the cap was switched out. Modern fixtures use an SMPS power supply so it just changes the PWM output to be at a higher level in the beginning and then backs off.
 

Electric-Light

Senior Member
Short over-simplified version, the "starter" was a capacitor (condenser) that provided a voltage boost to start the excitation of the plasma in the lamps. Once started, it was easier to keep it excited with the ballast output, so the cap was switched out. Modern fixtures use an SMPS power supply so it just changes the PWM output to be at a higher level in the beginning and then backs off.

No, the starter is a gas bulb. A reactive ballast is wired in line with the lamp and the glow starter straddled across the lamp through the other two pins on the lamp. The arc heats up the electrodes and causing one the probes to mechanically short out and current flow through the lamp filaments.

As the probes cool off and release, it causes the ballast to produce an inductive kick back which strikes the arc in the lamp.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The one detail not explained in the video is why the glow lamp does light again after the contacts open. The gas in the glow bulb and its pressure causes its strike voltage to be lower than the line voltage (ballast output voltage) but higher than the tube arc voltage once it has warmed up and struck.
 
Status
Not open for further replies.
Top