Do all energy efficient electric ballasts upconvert the source
frequency of 60Hz to 20-50kHz?
I have a history of symptoms with normal fluorescent lighting
(60Hz/120 blinks per second). I usually put up with it, but feel
better in sun or incandescent lighting.
Assuming you mean the compact fluorescent lights, the answer is yes! They
have to operate at this high frequency to keep the internal transformer
hum-free (at least for our human hearing), small and inexpensive.
P.S. BTW in this kind of lights there is no "ballast".
| Do all energy efficient electric ballasts upconvert the source
| frequency of 60Hz to 20-50kHz?
| I have a history of symptoms with normal fluorescent lighting
| (60Hz/120 blinks per second). I usually put up with it, but feel
| better in sun or incandescent lighting.
You will still see 120 blinks per second. Even though the electronic
ballast is chopping the power up in thousands of fine slice per second,
it still has periods of time in which there is less voltage and the
light will still have 120 Hz modulation to it.
If the power were DC, an electronic ballast could make it flicker free.
DC would not work on an inductive ballast (the light would be seen as a
short circuit and could result in an explosion), and electronic ballasts
may also require AC anyway. If one can work on DC, it might be indicated
as such. But is it worth building a DC power system just to remove the
I'm wondering if a 3-phase electronic ballast could be devised which would
selectively switch power among phases (there'a always power in at least 2
of them at any instant). That could eliminate the flicker, or at least
bump it up to 180 or 360 Hz. But it would play hell on the neutral wire
if a lot of lights were done this way (it would be distributing the load
on 3 phase hot wires, but the neutral would have to be carrying it all).
Sorry never seen a 3 phase ballast. On 3 phase 480 volt circiuts for
lights they are still single phase lights, either 277v from hot to a
netural or 480 between hots, and use a contactor for switching.
besides lighting circuits in most applications do not draw much power,
not enough to be 3 phase. even 1800 watt vapor lamps are single phase.
Also your second question about the netual, in a 3 phase circuit even
wye connected if the load is balance thereis no netual current. if
unblanced at the worst the maximum load on the neutral is the load on
just one of the hot legs, as the phases add up to zero current.
Not always that simple. If the load is non-linear, such as a three,
separate phase-neutral full-wave rectifiers, the neutral current can be
*more* than any single phase current. If the magical 3 phase circuit that
phil postulated shifts the load from phase to phase as each phase voltage
changes, that would be a non-linear type of load and the rms current of the
neutral could be higher than rms current through any single phase. Even if
all three phase currents are exactly equal. They only cancel out to provide
zero neutral current if they are sinusoids.
in article firstname.lastname@example.org, Tim923 at
email@example.com wrote on 9/20/04 1:42 PM:
The problem is the ballast. Inductors offer a cheap and low-loss way to
stabilize current flow through the tube. To do so on dc will require
electronics or an inductor in the primary circuit of the rectifier.
in article AII3d.4935$Ii2.148@trnddc09, bushbadee at firstname.lastname@example.org
wrote on 9/20/04 3:20 PM:
You got a patent for that? When? What is the patent number? Did it ever earn
a royalty? I know how a bridge circuit can be connected to an ac circuit in
many ways, but what do you mean by "inserted in series"?
Sure did get a patent.
Got one in the US, Japan and Germany on it.
If I gave you the patent no you would know my name.
Well the power came in, went through a capacitor to the lamp, from the lamp
to the bridge and from the bridge to the return.
Only about 14 parts total and it regulated from about a couple of micro amps
of lamp current to a full 60 ma which was the lamp max.
There was no styrating of the lamp at any brightness.