today i did an experiment involving a 175 Watt Mercury vapor Lamp...a 70 Watt HPS Ballast and Two Capaciators....

i connected the lamp to the HPS Ballast and naturally it wouldnt start....so i wired the lamp parallel to Two Caps...one 275 volt and the other 400....and then the lamp Struck....and i ran it for about ten minutes...upon removing the capaciators from the Circuit..the lamp immediately shut off....so i concluded the boost in voltage by the capaciators was what was allowing the lamp to opperate on the High Pressure Balast which is mearly a 120 Volt Choke.

You connected the lamp IN PARALLEL with the capacitors? Did it flicker? Never do this again as it stresses the lamp's electrodes a lot and may cause quick blackening and death.

Anyway, that lamp struck because of resonant voltage rise on the caps.

You connected the lamp IN PARALLEL with the capacitors? Did it flicker? Never do this again as it stresses the lamp's electrodes a lot and may cause quick blackening and death.

Anyway, that lamp struck because of resonant voltage rise on the caps.

it didnt Flicker anymore than it does when Fired up on the Specified Ballast....the lamp showed no Signs of Stress.

it didnt Flicker anymore than it does when Fired up on the Specified Ballast....the lamp showed no Signs of Stress.

If the lamp could stand capacitive ballasting, we would already be using just a single capacitor for ballast (at least in Europe) but its not the case.

I'm not sure about the flicker, but what I'm sure about is that the cap causes a huge current crest factor (reactance ballast ~1.5, capacitor >5 ??) which is basically the peak-to-average current ratio, so the lamp will see large peak currents and this might decrease its useful life to a fraction of its original rating. Most mercury lamps are rated to a current crest factor maximum of 2 (the same as "constant wattage" ballast).

keep in mind this is Simply a Temporary Experiment....this is no Permenant Setup....the Lamp is already damaged prior to this experiment as a hole was Punctured in the lamps Outter Bulb.

keep in mind this is Simply a Temporary Experiment....this is no Permenant Setup....the Lamp is already damaged prior to this experiment as a hole was Punctured in the lamps Outter Bulb.

All right, I was just saying that this setup is not acceptable to run the lamp for any longer periods of time 

today i did an experiment involving a 175 Watt Mercury vapor Lamp...a 70 Watt HPS Ballast and Two Capaciators....

i connected the lamp to the HPS Ballast and naturally it wouldnt start....so i wired the lamp parallel to Two Caps...one 275 volt and the other 400....and then the lamp Struck....and i ran it for about ten minutes...upon removing the capaciators from the Circuit..the lamp immediately shut off....so i concluded the boost in voltage by the capaciators was what was allowing the lamp to opperate on the High Pressure Balast which is mearly a 120 Volt Choke.

This is exactly the way, how HF do ballasts work: It act as series resonant LC circuit, what generate HV for ignition and then the capacitor is nearly eliminated by low resistance of an arc. Only differences (all related to high frequency) are component values (much smaller L and C) and the fact, the voltage/current waveform are much faster then the ionisation level might follow, so the ionisation stay nearly constant, yielding nearly linear resistive behavior of the arc, so no restrikes, so no current spikes. There the lamp circuity is supplied from e.g. ~150V (in Europe, without PFC), but the arc voltage might still be ~180V (e.g. F70T5HO fluorescent)...

I've never tried this experiment...but I would guess that if 120v choke supplies enough current, the MV lamp would cycle; but with cap in parallel, the lamp would flicker as it reaches the threshhold of cycling because the cap voltage would rise as lamp tries to extinguish and cap would still keep lamp lit...hence back and forth rapidly. A (120v) 70w choke ballast on 175w MV might not be enough current to cause this though. Also, yeah it seems this would be h*ll on the lamp in short time. Only my untried theory...

today i did an experiment involving a 175 Watt Mercury vapor Lamp...a 70 Watt HPS Ballast and Two Capaciators....

i connected the lamp to the HPS Ballast and naturally it wouldnt start....so i wired the lamp parallel to Two Caps...one 275 volt and the other 400....and then the lamp Struck....and i ran it for about ten minutes...upon removing the capaciators from the Circuit..the lamp immediately shut off....so i concluded the boost in voltage by the capaciators was what was allowing the lamp to opperate on the High Pressure Balast which is mearly a 120 Volt Choke.

after Burning a While with the Cap the 175 Watt MV has Stabalized on the 70 Watt HPS Ballast without Cycling or Flickering....and it seems to Reach Full Regimine....now it can be stably opperated without the Cap.