[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: ? Comment about use of electronic ballasts ?



Matt wrote:

I spoke with a lighting distributor of Magnetek ballasts, and the guy told
me that using an electronic ballast on the T-12, T-10, and non-energy saving
type T-8's bulbs will overdrive the bulbs and cause them to burn out
quicker.  Before then when I spoke with an engineer at Magnetek he never
mentioned this problem.  Has anyone else ever heard about this before?

I reply:

This would not suprise me at all.  It is importatnt to match the right
ballast with the right lamp or unintended side effects can occur. I don't
know of any ballast that is intended to run 25 watt 36" T8s and 30 watt 36"
T12s.

Matt wrote:

But as more aquarium light companies convert all the sizes to the real T-8's
I want to be able to
switch to those bulbs w/o needing new ballasts.  That is why I originally
thought that I should get electronic type ballasts.  Also the ballasts I'm
looking at are rapid start; should they be instant start instead?

I reply:

There is no reason to ever switch to 25 watt T8 lamps unless you buy an
appropriate ballast that has a high ballast factor. If the B.F. is not
significantly over 1.0 then you are going to get less light than you would
with the 30 watt lamps. As far as I know Magnatech doesn't make that type of
ballast. Whether you are running 25 watt lamps or 30 watt lamps an
electronic ballast is a good investment. Very quiet, very energy efficient
and very reliable.

If I were you I would consider a 36" PC from AH Supply. DIY systems make
more sense on a 48" long tank. 48" lamps and the ballasts and fixtures for
them are very common, cheap and available compared to the 36" lamps.

Matt wrote:

On another topic, I'm building a canopy and reflectors for the lights
mentioned above and need help on the profile shape of the reflectors.  If
anyone has dimensions and angles for some of the elaborate, expensive
reflectors I'd greatly appreciate it.  I've searched the archives here and
on the Krib, as well as the web and have not found anything of help.  I'm
going to use aluminum flashing to make the shape, and then adhere 'Clear
Mirror' to the aluminum.  (Clear Mirror is a product made by 3M that has
over 99.9% reflectivity).

I reply:

I use a similar material but I have not had really good success with glueing
the stuff onto the reflector. The glue reacts with the aluminum coating. I
have had better success with bending it around the inside of the reflector
and attaching it at the edges only. If you have access to a metal break I
would just roughly bend a shape that is no more than 8" wide for a 2 lamp
relector and maybe 4" deep. If you bend the edges of the reflector over like
this:

              _____________
              /        O    O       \
            /                             \
            |/                            \|

The mylar can be contained within the reflector without any fasteners. This
allows the mylar to form a smooth parabolic surface. The width of the mylar
controls the depth of the parabola.

The reflector should as much as possible direct the light downward so that
light striking the water surface will not be reflected. Also, the reflector
should not direct light back toward the lamp. Since light comes off of the
surface of the lamp at all angles this is all easier said than done. The
smaller the lamp diameter the easier it is to do. I would try and copy an AH
Supply reflector or a Triton reflector.

Wayne