As I mentioned, the ballasts are made by Motorola and distributed by both
Motorola and GE. The Motorola packet was better, with some general info
(a portion of which even the electronically disabled could follow) and a
neat spin toy to show "flicker" that goes forever with a single twist. The
GE catalog was full of flashy graphics, with little context & harder to
make sense of, at least for this non-professional.
To summarise, the ballasts are made mostly for 3 and 4 foot bulbs of the
T-8 diameter (only one is at present available for the T-12, in 4 foot
length). They are, the book says, easy to retrofit ("poke in"), can take
an ordinary dimmer, don't generate the heat, radio static or flicker of
magnetic ballasts, and save some current without loss of light. They say.
Another benefit, for those who do precision printing, is that the magnetic
ballasts take 90 minutes to reach constant output level, reached instantly
by the electronic. (I know someone who "warms up" his lights for an hour,
apparently not enough.) As the article suggests, therefore, testing light
output before 90 minutes with magnetic ballasts would include some fumpher
factor: "When the [magnetic ballast] light output stabilizes, the light
output decreases." The "ballast factor" is the difference between .875
constant output with the electronic, and .925 initial output on the
magnetic, lowering in 90 minutes to the same .875. Whether this is a
miniscule or a significant difference, IHNI. ("I have no idea."!)
The cost seems comparable to magnetic or not much more, so if they have
your size, there seems to be no downside. (Nothing, it seems, for my 6 and
8-foot ceiling fluorescents or my 2-foot UV light table.)
Call either the GE or Motorola 800 number in your area. Or your area
distributor for either company.
Motorola is 1/800-MLI-0089 in the States.
I don't have an 800 number for GE & there's none in the catalog.The GE
lighting office in NYC is 212/243-0051.
Judy