Flouresent lighting questions for the wizards

Gunner · 2012-09-09T13:55:34+00:00

Ive got a shop 14' wide by 55' longFor years Ive had a series of 4' double tube florescent fixtureshanging and have had no issues with them. The shop is unheated (California) but the winter temps do go down tothe high 30s at night in the winter time on occasion. Ive had somelights have issues coming on at those temps in the past.I scored a bunch of 8' (2 sets of (2) 4' tubes) fixtures that run on277vts. Some 10 of them or more, with nice speckle covers that Idlike to put up and replace the single 4' fixtures.Ive been using a couple 3 tube, 4' fixures that are already 277 voltsin odd areas and running them off a 240/120 single phasetransformer..hooked up backwards, with no issues, for a number ofyears.My "HV" (mains) standard power runs between 240 and 250 volts out inthe shop off the breaker panel, but Ive been concerned about isolatingthe lamps so Ive used old machine tool transformers hooked upbackwards.Ive been checking the "new" 4 tube fixtures out and they all seem tofire up well and Ive got several new cases of 4' T12 bulbs in theracks along with a partial case of T8 4' tubes. Ive stuck in T8s inthe older fixtures over the years and they work fine even missmatchedwith a T12..but I generally replace both.So at this point in time...Im getting ready to put up the 8'fixtures..but Im concerned about how to power them up.1. Is it "kosher" to simply hook them to an unused 240 single phasebreaker?2. Is it better to use a transformer and isolate them from the "mainspower"?3 If I should install a transformer...where do I find a 240-277 stepUP transformer cheaply? Or several of them (welding shop needs one aswell4. How many watts does each 4' pair actually draw? 90 watts? Each ofthe 8' fixtures has 2 ballasts, one for each 4' pair.I tend to work out there at night..and with Pacific Greed andExtortion charging me far more than the national average...my powerbills at HOME have been around $400 a month this summer. This with a1hp swamp cooler motor running 24/7....

Sep 09, 2012 27 Replies

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Gunner 14 years ago

Arnt they so rated? I assumed (ass you and me..yah I know) that they would be rated for at least that much. No true?

And thanks!!

Gunner

-- "Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

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Gunner 14 years ago

Indeed. While my shop has VFDs, and other Stuff..I like to keep it as "clean" as possible. Ive had to hunt down too many issues in the machine shops I service to jumble it all up

Gunner

-- "Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

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Bruce L. Bergman (munged human readable) 14 years ago

5W+ VHF or UHF two-way handheld radio, preferably on an unused frequency. Stick the antenna between the bulbs, and sweep back and forth while keyed, saying "AAAAAuudio!" - Bing! External Starter.

Still means you've got a lamp with a bad filament, or a weak ballast that isn't putting out start pulses, or it's way cold below the rated Start temperature. The first two need fixing.

-->--

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Gunner 14 years ago

Excellent suggestion!! I have a coffee can filled with new fuse holders . Much obliged!!

Gunner

-- "Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

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Michael A. Terrell 14 years ago

Or the fixture isn't grounded. I ran into a new fixture that was installed on old knob & tube wiring that was erratic. Touch the fixture and it would light. I put a .01µF 2KV ceramic disk capacitor between neutral & the floating fixture to cure it.

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David Lesher 14 years ago

If the lamps fire on 240, I can't see any problem just using

240V. If they don't ignite, then boost may be necessary. GE seems to say their magnetic 277V ones are rated "Line Voltage Regulation (+/-) 5 %" but not sure what that means... less light output at lower voltage? Won't work at all?

Test a unit for 24H and see what temp the ballast is...

[There are no 240V one listed but the newest electronic ones are often "120-277"...]

While the 277V ballasts were manufactured to run from a 480 wye to neutral; I can not believe that they have one leg of the input grounded. But measure with an ohmmeter, and be sure. And do a bench test with a unit safely fused.

Measure. Best way would be a test setup with a 120V -> 240/277 transformer, and then put a Kill-A-Watt

in the 120 supply. This will tell you the true watts of a fixture, and the current & power factor. {Watts * time is what you pay PGE for; but the transformers are limited by current....

Read what DoN said about relays. Control the fixtures with relays to gain the flexibility you want. Note the tradeoffs in lamp life with cycling.

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