Body
Hi Mick,
The ballast of a HID (High Intensity Discharge) lamp would have to be an inductor. https://wiki2.org/en/High-intensity_discharge_lamp. https://wiki2.org/en/High-intensity_discharge_lamp
The capacitor could be for a start discharge to get the arc ignited. This would be just a short pulse and thus wouldn't require a continuous high current through the capacitor.
Here is a page with a schematic for an electronic ballast for HID lamps: https://www.repairfaq.org/sam/jshidbal.htm https://www.repairfaq.org/sam/jshidbal.htm This circuit outputs DC current even though the Wikipedia article tells that DC isn't good for this kind of lamps. The C7 capacitor is the output capacitor that has the total voltage across it. This capacitor won't have big current through it as the current is limited by the series capacitance of the voltage multiplier and the output series resistor R3. A motor run capacitor will have the full run current of the help winding through it and thus must be able to handle that current through extended periods of time. Choose the capacitor for not heating above what the manufacturer recommends. The good capacitors are normally expensive as compared to the bad ones. Check the datasheets to see if fit for the purpose.
The schematic from the above link.
Regards
Ole
---In [email protected], <mkjekyll@...> wrote :
Hector,
If you can respond what is the difference between a HID lighting ballast
cap and a run capacitor?
The lighting caps are much less expensive, both are oil filled and both
can handle a good amount of wattage.
Is the internal build of say a run cap different offering higher Q or
are they somewhat interchangeable?