Gunner wrote:
Michael A. Terrell wrote:
What's the big deal? A single 24 V transformer in boost
configuration will drive all the lights. 277V is 115% of 240, and 264 V
(240+24) is within 5%. Standard light switches are rated for 277 volts.
80 watt lamp at 277 draws 0.2888 amps. Round that up to .3A per tube
for easy calculations. 40 Watt would be about .15A. 55 feet only has
room for a little over six eight foot fixtures in a single row, so the
maximum load would be .6A * 6 or 3.6A if all six fixtures are on. If he
used the other four fixtures over machines, that would be another 2.4A
for a total of 6A at 277 Volts. You don't need, or even want isolation
on the fixtures. The housings should be grounded, so a fault will blow a
fuse, or trip a breaker. They used to put a fuse in some brands of
eight foot fixtures, so a failure wouldn't take out all of the light
fixtures. Not a bad idea, but the fuses need to be rated for 600V
circuits to prevent a plasma arc inside the fuse.
You can even wire the fixtures to turn on pairs of tubes instead of
all four, with some ballasts.
So let me get this straight..Im very weak here...
input side is 240 volts. Output side is 24 or 32vts..simple step down
transformer, right?
Yes. Like a control or rectifer transformer used to provide 24 volts
vopr a machine.
Hook one side of the 240 volts to one 240 term..and wire a jumper
around to the low voltage side and connect to (1) 24 volt term
The othe 240 hot goes to the other 240 input term..
The remaining 24 volt OUTPUT terminal then becomes 264 volts output
along with the jumpered 240+24 volt term?
Do I have that correct?
Yes. She the photo in the link to help you visualize it. You can
think of it as a Variac set in boost mode, if that helps.
And if so...where do you recommend I put the fuse(s), on both sides
of the transformer..single input and single output terminals?
http://acmefaq.files.wordpress.com/2...buckboost3.jpg sows how to
connect a transformer in boost configuration. The 'H' windings are the
240 side. The 'X' windings are the low voltage secondary. If they are
connected in phase, they raise the output voltage. If you reverse the
phase, it will subtract from the line voltage. Both sides show split
windings, so just ignore the H2 to H3 and the X2 to X3 connections if
your transformer has single windings. I would put a 10 to 15 Amp fuse
or breaker after the transformer, and use a 15A circuit breaker in the
panel.
Feel free to email me if you have any other questions.
I'm VERY weak on transformer work. Shrug. The stroke took a lot of
what I did know..away, from the looks of it.
I may..may have (3) decent sized "buckboost" transformers on a board
out on top of one of the racks. Used for bucking UP machine tool
voltages as I recall. Ill have to climb up and check. They were as I
recall..used on a 3 phase machine..hence 3 of them.
I would mount one in a box, if the terminals are exposed. If they
have a wiring compartment, just mount it next to the breaker box & wire
it in. This is like that repair I did last year to that Ineco pipe
bender that was reporting low voltage. BTW, they lost a second computer
in that thing. Luckily, I was able to repair the oldest one so they
didn't have to wait for a replacement from Italy. I'll try to post
photos of the second controller before & after I repair it. They will
be posted on my Fliker account, until I start a repair blog.
http://www.flickr.com/photos/materrell/