Discussion:
Question about FC8T9RS Wiring
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Joe Gandalf
2015-03-25 20:32:07 UTC
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Hi all,

It's been a while since I've been here (used to be one of my favorite NGs).

I just picked up an old cantilevered magnifying work lamp - large
magnifier in the center, with the FL lamp surrounding it. The fixture
had nothing on the tail end of the cord (no plug, etc). While cleaning
it up I found that there was no ballast, nor any room for a ballast, in
the lamp housing. It has an old Leviton pre-heat type switch (push &
hold to turn on, then release; push again to turn off, like the 388
model) on the housing.

The confusing thing for me is that it appears as though this fixture
still has the original zip cord from the base up to the lamp housing,
where it is wired into the switch & thence to the lamp socket. One AC
lead direct to the W socket wire, the other to one black lead of the
switch - the two blue switch wires go to the red leads of the socket &
the other black switch wire goes to the black lead of the socket.

Is it possible that this ran off of 120 VAC without any ballast? I have
seen nowhere that one could be mounted, except at the end of the zip
cord farthest from the lamp. I also can find no wiring diagram for the
old simple choke (simply 2-wire) type ballasts; all of the "2-wire"
ballasts I have seen advertised have 2 wires going in and 4 coming out.

I want to get this thing going, but I am reluctant to just stick a plug
on it and try it out.

What say you?

PS - please respond to this newsgroup, as my email address is just a
spam-catcher. Thanks.
m***@att.net
2015-03-25 21:32:07 UTC
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While cleaning it up I found that there was no ballast, nor any room
for a ballast, in the lamp housing.
Most of the fixtures like this that I have seen had the ballast in a box
at the base of the fixture, right above the clamp or swivel that holds
the fixture to the desk. On some fixtures, it would be mechanically
possible to remove the box and attach the clamp or swivel directly to
the arm - maybe somebody did that.

I vaguely remember seeing a different type of fluorescent fixture a long
time ago that had the ballast as a lump in the power cord.
Is it possible that this ran off of 120 VAC without any ballast?
I don't think so.
I also can find no wiring diagram for the old simple choke (simply
2-wire) type ballasts; all of the "2-wire" ballasts I have seen
advertised have 2 wires going in and 4 coming out.
Try
http://nemesis.lonestar.org/reference/electricity/fluorescent/preheat.html
and scroll down to "Typical Manual Pre-Heat Fixture Wiring Diagram".
The only difference for you is that the "off switch - normally closed" is
probably on the other side of the ballast - between the ballast and the
tube, rather than between the line and the ballast. Otherwise, that
diagram is consistent with the wiring as you described it.

I have seen small 2-wire ballasts on the shelf at Home Depot. They look
just like a small power transformer (10 to 20 watts or so), but only
have two wires. They are with all of the other fluorescent ballasts.
Maybe try one of those, and if the lamp comes to life, use something
like a 2-gang electrical box with blank cover plate to mount the ballast
in.

Matt Roberds
Joe Gandalf
2015-03-25 22:20:37 UTC
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Thanks for the quick reply, Matt! I wasn't sure if anyone even checked
this list with any frequency; the good old days of Usenet are long gone,
sadly. I partly blame Google for "democratizing" the posts so that all
the creeps & spammers could weasel in.


Yeah, about the ballast box - I seem to remember that my previous
version of this lamp (now MIA - probably somewhere in my barn) had such
a block at the base; this one must have had a wall-wart type plug with
the ballast enclosed. I'll look into HD, or maybe even our local
electrical supply house for the old style ballast. Do you know what
specs should be acceptable, if they don't have an exact replacement for
the circline lamps?


As an aside, do you know of a comparable Yahoo (or other) group that
reliably discusses lighting with the energy that sci.eng.lighting used
to have 10 years ago? I really enjoyed the discussions back then, and I
learned a lot. I see that Victor & Andrew are still around, how about
Sam & Don? Ionnis? The names of the rest of the usual suspects escapes
me for now...

Cheers,
Joe
Post by m***@att.net
While cleaning it up I found that there was no ballast, nor any room
for a ballast, in the lamp housing.
Most of the fixtures like this that I have seen had the ballast in a box
at the base of the fixture, right above the clamp or swivel that holds
the fixture to the desk. On some fixtures, it would be mechanically
possible to remove the box and attach the clamp or swivel directly to
the arm - maybe somebody did that.
I vaguely remember seeing a different type of fluorescent fixture a long
time ago that had the ballast as a lump in the power cord.
Is it possible that this ran off of 120 VAC without any ballast?
I don't think so.
I also can find no wiring diagram for the old simple choke (simply
2-wire) type ballasts; all of the "2-wire" ballasts I have seen
advertised have 2 wires going in and 4 coming out.
Try
http://nemesis.lonestar.org/reference/electricity/fluorescent/preheat.html
and scroll down to "Typical Manual Pre-Heat Fixture Wiring Diagram".
The only difference for you is that the "off switch - normally closed" is
probably on the other side of the ballast - between the ballast and the
tube, rather than between the line and the ballast. Otherwise, that
diagram is consistent with the wiring as you described it.
I have seen small 2-wire ballasts on the shelf at Home Depot. They look
just like a small power transformer (10 to 20 watts or so), but only
have two wires. They are with all of the other fluorescent ballasts.
Maybe try one of those, and if the lamp comes to life, use something
like a 2-gang electrical box with blank cover plate to mount the ballast
in.
Matt Roberds
m***@att.net
2015-03-25 23:41:44 UTC
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I partly blame Google for "democratizing" the posts so that all the
creeps & spammers could weasel in.
This problem predates Google. I read the Green Card Lawyers spam over
a dialup modem. Web forums are easier for many people to use, and more
importantly these days, easier to run ads on.
I'll look into HD, or maybe even our local electrical supply house for
the old style ballast.
I checked Home Depot's web site and the ballast I remember seeing there
sells for about $7.
http://www.homedepot.com/p/GE-Magnetic-Metal-Pre-Heat-Fluorescent-Ballast-GEM120PH120DIY/203959172
However, it says it is for F14T8 up to F20T12 lamps; it doesn't say
anything about Circline lamps. Official specs here:
http://www.gelighting.com/LightingWeb/na/smartcatalogs/Lighting_and_Ballasts_Section_15_Ballasts_Magnetic.pdf

The "official" Circline ballast that they sell for $19 is the kind with
two line wires on one end and four lamp wires on the other end. It
includes the lamp connector on a short cable, so it probably won't fit
in your fixture.
http://www.homedepot.com/p/GE-Magnetic-Ballast-for-1-Lamp-Circline-22-or-20-Watt-GEM1FC8T9RS120DI/204005261
Do you know what specs should be acceptable, if they don't have an
exact replacement for the circline lamps?
Philips says one of their FC8T9 lamps is 0.37 A lamp current:
http://www.lighting.philips.com/main/prof/lamps/fluorescent-lamps/tl/circline/928028403335_NA/product
So, if you can find a ballast that puts out about that much current, you
should be OK. I tried to look up the specs on some of the lamps that
the $7 GE ballast supports, but I wasn't able to find anything useful
from either GE or Philips. I *suspect* that the HD ballast will run
your lamp slightly underpowered, since the most it lists is a 20 watt
lamp, and yours is 22 watt.
As an aside, do you know of a comparable Yahoo (or other) group that
reliably discusses lighting with the energy that sci.eng.lighting used
to have 10 years ago?
Not that I know of.
I see that Victor & Andrew are still around, how about Sam & Don?
Don Klipstein is still updating his Web site.
Ionnis?
For a while, his Web site was still up, but he took down his nifty set
of spectrum and spectroscope pages. Now it looks like the whole site is
down.

Matt Roberds

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