Gunner wrote in
:

Ive got a shop 14' wide by 55' long

For years Ive had a series of 4' double tube florescent fixtures
hanging and have had no issues with them.

The shop is unheated (California) but the winter temps do go down to
the high 30s at night in the winter time on occasion. Ive had some
lights 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 on
277vts. Some 10 of them or more, with nice speckle covers that Id
like to put up and replace the single 4' fixtures.

So these fittings are intended for 277V (star) operation off a 480V
(delta) three phase supply.


Ive been using a couple 3 tube, 4' fixures that are already 277 volts
in odd areas and running them off a 240/120 single phase
transformer..hooked up backwards, with no issues, for a number of
years.

Many ballasts are dual rated 208/277V, so correct operation off 240V is
not surprising.


My "HV" (mains) standard power runs between 240 and 250 volts out in
the shop off the breaker panel, but Ive been concerned about isolating
the lamps so Ive used old machine tool transformers hooked up
backwards.

As the fittings are rated for use with a 480V three phase supply, your
concerns are almost certainly unjustified.

Ive been checking the "new" 4 tube fixtures out and they all seem to
fire up well and Ive got several new cases of 4' T12 bulbs in the
racks along with a partial case of T8 4' tubes. Ive stuck in T8s in
the older fixtures over the years and they work fine even missmatched
with 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 phase
breaker?

Yes - but only if they are dual rated.

2. Is it better to use a transformer and isolate them from the "mains
power"?
Two questions, but lets leave isolation aside.
You need a boost transformer to 277V (nominal) if the ballsts are not
dual rated.

3 If I should install a transformer...where do I find a 240-277 step
UP transformer cheaply? Or several of them (welding shop needs one as
well
Any transformer with a 240V primary and a 30-40V secondary can be wired
as a boost autotransformer. However this DOES NOT PROVIDE ISOLATION
Asuming a 35V secondary, the primary only carries 15% of the lamp curent.
If the secondary current rating is sufficient, its good, Dont worry about
the VA rating. An autotransformer will be much smaller/cheaper than any
other solution.

N.B. it would be preferable to use a pair of 18V transformers to boost
each side of the supply equally to keep the 277V output centered on
neutral. This is quite possibly not to code, so wire a suitable wall
mount male connector to the lights and build the transformer in a
'portable' housing with flex leads.


4. How many watts does each 4' pair actually draw? 90 watts? Each of
the 8' fixtures has 2 ballasts, one for each 4' pair.
Data should be on the ballast. Add them up. If in doubt, MEASURE!

I tend to work out there at night..and with Pacific Greed and
Extortion charging me far more than the national average...my power
bills at HOME have been around $400 a month this summer. This with a
1hp swamp cooler motor running 24/7. (which really hurts!!!)

Id like to have lighting in the shop that will work for me..but doesnt
break the bank. Work has slowed down tremendously (not had a service
call in a week and a half) and its not going to get much better Im
afraid...California and the US manufacturing has just declined..yet
again.


Id like to find some pull chain lighting switches that I can mount on
each 8" fixture to either kill the entire fixture..or just half of it
(double ballests) and help keep the lighting costs down as well. Ebay
has "pull chain" switches for $4 each..but that will add up fairly
quickly if I install 10 lights.


Any suggestions/recommendations on setting up my lighting that will
not break the bank?


Thanks

Gunner

HTH
Ian.


--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
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