Dave wrote:
> "Don Klipstein" <don@[EMAIL PROTECTED]
> wrote in message
> news:slrngc0sav.mpp.don@[EMAIL PROTECTED]
>> In <PLKdnQXKYtWlWSLVnZ2dnUVZ_jCdnZ2d@[EMAIL PROTECTED]
>, Dave
wrote:
>>
>>> It seems to me that a flourescent ballast is probably just a
transformer
>>> and
>>> a high-voltage electrolytic cap. And when it "goes out" it's probably
>>> because the cap failed. If these are true, could I just replace the
cap
>>> and
>>> make it work again? Assuming (hate that word) of course that I could
get
>>> the ballast open. What thinks the group? Please offer whatever
laughing
>>> criticism or encouragement you feel is appropriate. I do not need a
fire
>>> hazard in the kitchen...
>> There are several different kinds of fluorescent ballasts.
>>
>> 1. Simple choke - has 2 leads, usually used with a starter
(occaisionally
>> a "push-to-start" switch). There is normally no capacitor.
>>
>> When they fail, there is generally no repair other than rewinding
>> (extremely unlikely to be worth the time and effort), and sometimes the
>> core is welded together.
>>
>> 2. High leakage reactance autotransformer - has 3 leads, and is
>> effexctively a choke combined with a step-up transformer. Same story
as
>> 1.
>>
>> A variant is the 1-lamp trigger start ballast, which has filament
>> widnings added. It is still essentially non-user-serviceable.
>>
>> 3. The USA-usual "traditional" dual-4-footer - high leakage
>> autotransformer with a capacitor in series with the secondary. Also
has
>> filament windings and a small capacitor (in the ballast case along with
>> all other parts) to leak a small amount of current around one lamp to
help
>> start the other when both are not conducting but voltage is applied.
The
>> 2 lamps are in series with each other.
>>
>> If the lamp-series capacitor (which is not electrolytic) shorts, lamp
>> current will be somewhat high and ballast input current will be very
high.
>>
>> There are similar "trigger start" ballasts for 2 2-footers.
>>
>> The case is usually packed with tar. This one is also essentially
>> non-user-serviceable.
>>
>> 4. Electronic ballasts - more repairable than the others, but only by
>> those who know how to troubleshoot and repair them *safely*.
Capacitors
>> may store charge, and improper repairs may add a fire risk.
>> It may be difficult to verify that replacement parts are of
>> suitable grades (temperature rating, life expectancy at given
temperature,
>> voltage and frequency, also failing less catastrophically, any flame
>> retardance/resistance) and with suitable characteristics (such as
losses
>> sufficiently low to prevent overheating - and capacitors have 2 main
>> losses).
>> Also, one is unlikely to repair a ballast for less (including value of
>> time) than to replace it.
>>
>> Bottom line: Fluorescent lamp ballasts are generally unrepairable.
>>
>> - Don Klipstein (don@[EMAIL PROTECTED]
)
>
> Thank you, Don. This backs up the conclusion I had basically come to,
> making me feel better about replacing the offending ballast. Much
> appreciated.
>
> Dave
>
>
And also all the smoke leaks out!!
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