Author Topic: Little single "U" fluorescent night light  (Read 1362 times)
Powell
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Little single "U" fluorescent night light « on: August 04, 2011, 10:00:57 AM » Author: Powell
Fred's Super Dollar has them and they don't have very good life. The last one failed last night and it was installed on May 12.  I tore one apart and each end has 3 wires going into it. 

I think John (Dieselnut) has seen this type before.


Powell
Logged

NNNN!

Ash
Member
*****
Offline

View Posts
View Gallery


Re: Little single "U" fluorescent night light « Reply #1 on: August 04, 2011, 10:38:02 AM » Author: Ash
Is it wih stqarting probe electrode and connected with starting resistors like MV arc tube ? If so then it's basically instant start, and probably kills the electrodes quickly
Logged
Powell
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: Little single "U" fluorescent night light « Reply #2 on: August 04, 2011, 12:48:06 PM » Author: Powell
Maybe so, but it was only turned on ONCE and had been on 24/7. It had not appeared to age (much) like the others, but it was black on one end and much dimmer this morning. The others I have HAD lasted a BIT longer, but not by much. They aren't very expensive so running tests for life might be fun.  I tore the last one apart and it is VERY     V E R Y     bright in the microwave...... ;D :o
Logged

NNNN!

DieselNut
Member
*****
Offline

Gender: Male
View Posts
View Gallery

John


jonathon.graves johng917 GeorgiaJohn
Re: Little single "U" fluorescent night light « Reply #3 on: August 04, 2011, 01:38:30 PM » Author: DieselNut
Powell, you are correct! My little 1.5 watt fluorescent nightlight is this type. A member here said it is indeed "probe start". Seems reliable. Thee thing seems to run longer @ EOL than at full power! It ran nearly 2 years 24/7 and has probably been close to that at about half power. It gets flickery sometimes and you can hear it "pinging" a little as it attempts to go to full brightness. My mother had one run over three years at about half brightness, with about 2/3 of the tube blackened!
Logged

Preheat Fluorescents forever!
I love diesel engines, rural/farm life and vintage lighting!

Medved
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: Little single "U" fluorescent night light « Reply #4 on: August 04, 2011, 01:43:01 PM » Author: Medved
They are, indeed, instant start, but with only few starts per life  this would not be of any significant wear.
More important is their ballast: Mostly only series capacitor power them with huge current crest factor (large spikes on reignition after current zero cross), what lead to quite fast electrode wear during operation.
Or one of the starting probe circuit is faulty (interrupted connection on the PCB,...), so it have higher reignition voltage in one direction, yielding lower current (and so even higher crest factor; the probes are used to reduce the reignition voltage as well) from the ballasting cap in one direction

And it may well be the capacitor itself to fail: If it is the "self-recovery" type and it goes frequently into breakdown, it may consumed all of it's cells (the self-recovery consist of many cells, each separated by a kind of fuse. When the cell break, the fuse disconnect it, so the rest may continue to work. All this structure is done in the form of thin metal layer structure deposited on the dielectric foil, creating one electrode in this way; the second is either done in the same way, or it is regular metal foil)
« Last Edit: August 04, 2011, 01:45:37 PM by Medved » Logged

No more selfballasted c***

Powell
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: Little single "U" fluorescent night light « Reply #5 on: October 24, 2011, 05:38:20 PM » Author: Powell
My last one made 1500 hours. It had  no marks on the tube, and when I woke up one morning it was black on one end, dim and rectifying.

Now I am on the ones that I got from the distributor because I whined. I got 4 packages.... 2 units to the package. The first one didn't work, but the other one in the package did.


Powell
Logged

NNNN!

Print 
© 2005-2022 Lighting-Gallery.net | SMF 2.0.19 | SMF © 2021, Simple Machines | Terms and Policies