China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

Fluorescent Tube ends being black, for two reasons:
(1) Tube of poor quality, which often appear on the market are often inferior lamps phenomenon - some even have time to start or not start;
(2) The fluorescent ballast starting current is too small, too long to start impact;
(3) Core ballast starting current is too large impact on the filament, easy to make lamp black and burnt lamps.core Ballasts are produced according to the standard, if used shortly tube ends that blackening, the lamp should be of questionable quality, and ballast irrelevant.
Burn
Magnetic Ballast is due to appear between the coils burn out due to short circuit or due to excessive temperature rise caused by short circuit caused by the coil. It is mainly due to: (a) have a lot of enameled pinhole (national standard is allowed per m ≤ 25 pcs pinhole) If you happen to be enameled pinhole pinhole between turns on, the voltage will be too high inter-turn short circuit occurs; (2) using the voltage is too high or long-term use in exceptional circumstances, because the voltage on the use of magnetic ballast extremely strict, each additional voltage 10V 35mA operating current will increase about; increased operating current voltage 20V will increase 70mA, 220V voltage if current is 400mA, at 240V voltage current is 470mA, in this case generally does not appear burned, but in exceptional circumstances (ie starter short circuit) lamp long period start conditions, which led to excessive temperature rise occurs burn. (So we usually find that the lamp is not lit or starter for a long time are in a closed state for a long time, you should immediately check whether the aging of the lamp burned out or the starter has been short, you should replace it immediately, otherwise it will cause high pressure sodium ballast high temperature accelerated the aging, seriously affecting their life can appear even burn.)