Lighting Capacitors ?

[mowhoong]

There are wide value of lighting capacitor, range from 4 uf to 50 uf.
but I am not sure which value to pick for my 40 W fluorescent light
run in 230 volts ac. Can any person help me in this .
Thanks and Regards

 

[Stephen J. Rush]

On Tue, 08 Apr 2008 00:51:36 -0700, mowhoong wrote:

There are wide value of lighting capacitor, range from 4 uf to 50 uf.
but I am not sure which value to pick for my 40 W fluorescent light run
in 230 volts ac. Can any person help me in this . Thanks and Regards

Lighting _capacitor?_ None of my line-operated fluorescent lamps has a
capacitor. I suppose one could use a capacitor instead of the usual
inductive ballast, but I've never seen it.

 

[terryS]

On Apr 8, 9:00 pm, d...@manx.misty.com (Don Klipstein) wrote:

In <Dtmdnf-_Wvr3s2banZ2dnUVZ_rXin...@comcast.com>, Stephen J. Rush wrote:

On Tue, 08 Apr 2008 00:51:36 -0700, mowhoong wrote:

There are wide value of lighting capacitor, range from 4 uf to 50 uf.
but I am not sure which value to pick for my 40 W fluorescent light run
in 230 volts ac. Can any person help me in this . Thanks and Regards

Lighting _capacitor?_  None of my line-operated fluorescent lamps has a
capacitor.  I suppose one could use a capacitor instead of the usual
inductive ballast, but I've never seen it.

  I have seen capacitive fluorescent lamp ballasts.

  Sometime in the late 1970's, I saw in the trash an already-antique
fixture with a "lead/lag" ballast - with one lamp leading and one lamp
lagging.

  Sometime in the early 1990's, I got a 3-4-or-so-watt plug-in fluorescent
"nightlight" with a capacitive ballast.

  Sometime in the mid 1990's, I got a 20 watt super-slim fluorescent
fixture of the Lights of America brand.

  In all of these cases, some inductance was added in series with the
capacitor.  Otherwise, the current waveform would be a spiky one with high
peak current, resulting in reduced efficiency (the low pressure mercury
arc is nonlinear in producing shortwave UV) and extra wear on the
electrodes.

  That lower wattage plug-in light now buzzes like mad - the inductor must
have become a little unglued.  I never did use it much - that's why it
still works at all after a good 15 years.

 - Don Klipstein (d...@misty.com)

Don haven't done any homework on this yet but your post gets me
thinking/questioning. About capacitive versus inductive reactance
fluorescent light fixtures.
Fixed plenty of two tube (115 volt 60 Hz.) fluorescents; not sure
what's inside the ballasts and with an ample supply of used spares we
just replace bits as necessary using same colour codes of wiring!
But also have several older 3 tube fixtures that seem to have been
modified/botched up, haven't analysed their circuitry yet. They need
quite a bit of TLC/repainting etc. if ever worth getting around to it!
Also cooking stove fluorescent lamps seem to employ a single winding
inductor about the same physical size as a tube radio output
transformer, in series with the single (typically 24 inch) tube.
Inductive reactance?
Best scrounge though has been a 40 foot plus row of electronic ballast
fixtures that are now on ceiling of basement workshop!All we had to do
to install and get them working was $25 of T10 tubes IIRC. Only
problem was getting permission to take the fixtures, mostly in good
condition the job foreman wanted us to take the whole lot; which would
have required a dump truck. We settled for 7 four tube, 8 foot
fixtures in back of our pickup! So that gives us a couple of spare
fixtures.
Any comments appreciated. Always willing to learn something. terry