Another era
- Thread starter wyreman
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gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Electrical Engineer - Photovoltaic Systems
Are those tubes threaded? Why?
In belief, man can do anything
Probably to increase surface area thus lamp output.
GE did and may still make from power groove VHOs that were similar.
Only source I found for the PowerGroove was Amazon ... they are very fond of them
http://www.amazon.com/GE-8pcs-F96PG17-White-Groove/dp/B005WZPUKS
GE did and may still make from power groove VHOs that were similar.
Only source I found for the PowerGroove was Amazon ... they are very fond of them
http://www.amazon.com/GE-8pcs-F96PG17-White-Groove/dp/B005WZPUKS
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- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I doubt that the extra surface area is an issue, since all of the UV hits the phosphors on the tube walls either way.
What I have seen is that the asymmetry causes the effective arc length inside the tube to be longer, changing the efficiency of the lamp while keeping the ballast requirement unchanged. That sounds a little odd too, but it is what I remember seeing in an ad.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Google to the rescue. This reference, (at the bottom of page two, since it is a non-searchable image) describes Power Groove.
It is actually both effects, plus a third.
1. The groove puts more of the phosphor close to the center of the arc (similar to the effect of using a smaller diameter tube, but with better cooling.) This increases the efficiency of the arc to phosphor energy transfer.
2. The arc length is 1 foot longer in an 8 foot nominal tube than a simple cylinder. That longer arc length increases the efficiency by allowing more optimal gas mixtures.
3. Part of one groove is designed to operate cooler than the rest of the tube. For a fluorescent tube the mercury vapor pressure is determined by the coldest spot in the tube and lower pressures increase efficiency. The T5 tube gets a similar performance boost from a cool area behind the filament at each end of the tube.
The tube requires a special ballast and so the contact arrangement at the tube ends is unique to the Power Groove.
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