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Participant

Join Date: Mar 2010
Location: Greenville, SC
Posts: 2

Fluorescent Lighting Problem

03/04/2010 11:06 PM

I have an issue with my Florescent lighting in which one bank of 2 36" Florescent tubes go out after 30 minutes of use. They then come back on for about 30 minutes and then go back off. The other bank of 2 36" Florescent tubes right next to it never does this.

What could be the problem???

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Associate

Join Date: Mar 2010
Posts: 26
Good Answers: 2
#1

Re: Florescent light issue

03/05/2010 12:25 AM

BAD BALLAST OR BAD NEUTRAL CONNECTION.

IF YOU ARE NOT A TRAINED ELECTRICIAN, BUY A NEW LIGHT!

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Anonymous Poster
#2

Re: Fluorescent Lighting Problem

03/05/2010 10:49 PM

replace both tubes or the ballast.

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2
Participant

Join Date: Oct 2009
Posts: 3
Good Answers: 2
#3

Re: Fluorescent Lighting Problem

03/06/2010 12:56 AM

Properly installed, fluorescent fixtures last decades. Make sure the ballast is bonded cleanly to the fixture, that the fixtures are bonded to ground via their supply cabling.

Properly done, even with new fixtures, means scraping paint off the ballasts' bond

attachment points. This done when new, the fixtures will operate for decades,

generate little or no RFI, with long tube life.

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Active Contributor

Join Date: Oct 2009
Posts: 14
#7
In reply to #3

Re: Fluorescent Lighting Problem

03/07/2010 8:05 AM

I'm not trying to put you on the spot, but rather I'm interested in this technology. Why must the ballast be bonded to the metal enclosure which is tied to earth ground? Why wouldn't the bulbs fire and remain lit if the bulbs and their connectors were removed from the metal enclosure?

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Participant

Join Date: Oct 2009
Posts: 3
Good Answers: 2
#9
In reply to #7

Re: Fluorescent Lighting Problem

03/07/2010 1:57 PM

There is a 0.005 microfarad rf bypass capacitor built into the ballast that shunts rf

generated to ground, if the can of the ballast is grounded, for one good reason. Two, these ballasts are painted with a non-conductive paint, so scraping the paint off

the mounting flange is indicated. Three, as taken from the Westinghouse Lighting

Handbook, page 3-35: "To ensure dependable starting under all circumstances any lamp operated on a rapid-start ballast must be mounted within one inch of a grounded metal strip that is one inch wide and runs the full length of the lamp."

We, in Canada, have a common-sense rule in our electrical codebook regarding that:

<Bonding Methods> 10-600 Clean Surfaces When a non-conductive protective covering such as paint or enamel is used on the equipment, conduit, or fittings, such coating shall be removed from threads and other contact surfaces in order to ensure

a good electrical connection. Removing the paint under the attachment point on the

ballast works even on ballasts that have been running hot for some time. When the

fixture has been running in the starting mode for some time the connection points

of the tombstone connectors deteriorate from thermal breakdown and then they

have to be replaced as well. Lastly wirenut connections to the supply conductors

are a concern where they make and break, blackening and worsening their grip...

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Active Contributor

Join Date: Oct 2009
Posts: 14
#11
In reply to #9

Re: Fluorescent Lighting Problem

03/07/2010 11:58 PM

Westinghouse Lighting

Handbook, page 3-35: "To ensure dependable starting under all circumstances any lamp operated on a rapid-start ballast must be mounted within one inch of a grounded metal strip that is one inch wide and runs the full length of the lamp."

This is the kind of answer I was looking for. I didn't know these lamps needed to be in proximity to a grounded plate. This answers some questions and symptoms I've run into over the years.

Thanks

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Anonymous Poster
#4

Re: Fluorescent Lighting Problem

03/06/2010 4:09 AM

Dear friend,

there are many reasons for the same problem,so to clarfy it you just interchange the main supply connection with each other(other bank)it will help U

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Power-User

Join Date: Nov 2008
Location: US - TEXAS
Posts: 196
Good Answers: 18
#5

Re: Fluorescent Lighting Problem

03/06/2010 7:10 AM

It's a bad ballast. All ballasts have a built in thermal protector, over the use they will get weak and then begin doing exactly what you describe.

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Power-User

Join Date: Jun 2008
Location: Olive Branch, Ms. USA
Posts: 124
#8
In reply to #5

Re: Fluorescent Lighting Problem

03/07/2010 11:33 AM

I concur with this post. In the past I was able to check T-8 and T-12 tubes by keying up a 2-way radio and passing the antenna along the tube.The RF would excite the gas and the tube would glow for a couple of inches on either side of the antenna. Just an additional FYI

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Anonymous Poster
#6

Re: Fluorescent Lighting Problem

03/06/2010 7:53 AM

Rgards.

What conditions you notice on this On/OFF cycle.

Any Flickering? If yes can you explain in simple.

Have you notice any Overheating of Ballast?

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Power-User
Engineering Fields - Power Engineering - New Member

Join Date: Nov 2009
Location: Abuja, Nigeria.
Posts: 126
#10

Re: Fluorescent Lighting Problem

03/07/2010 2:03 PM

Flickering is not peculiar to the florescent lamp circuit alone. It is very common in all blast related lamp systems. The Mercury vapour lamps, sodium lamps etc. Flickering is caused by th following,

1) Bad blast or choke

2) Bad starter

3) Low voltage

4) Bad tube.

Check the above for Ur problem.

Fluorescent systems affect radio systems. Radio systems is never used as a repair for fluorescent problems.

Dickson.

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Users who posted comments:

Anonymous Poster (3); brentgrimsrud (2); DABRAIN (1); Dickson (1); GRAY HAIRED OLD GOAT (1); noshorts (1); twomoons (2)

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