As the title suggests. 4.4uf 650v capacitor wanted for used with Philips BSX180H96 180w SOX gear.

 hace u thought of getting caps from microwave ovens
U may jave to put  a few in parallel  to add up the uF value

That's something to think about.

I'd get just a couple of good quality film capacitors from electronics supply house like RS. 2x2.2uF will give you 4.4uF needed. 650V rating is a bit vague - if it means AC, 630VAC/1000VDC or more capacitors will be OK.


 

Be careful here. The voltage rating is important. If you do what you are suggesting and wire the caps in parallel you will indeed double the capacitance but will half the maximum operating voltage. Far better to find two 8.8uf caps and wire them in series. That way you will get the 4.4uf and the voltage will be doubled. I had the same problem for a 131W sox e lamp. Two 6.8uf caps at 450vac gives 3.4uf at 900vac, more than the 650vac required and much safer to use.

half the maximum operating voltage

As far as I am aware this is completely false. Insulation thickness does not depend on any external factor including parallel capacitance.

Indeed, voltage rating stays the same for one and for few of them in parallel

Series is a problem, especially in DC circuits or circuits with significant DC offsets. Any tiny leakage in the capacitors or in the external assembly (like contamination on the PCB) will lead to the DC voltage (or DC component of thevoltage) being divided between the capacitors according to the leakage, and not to the main (and well controlled) parameters. This essentially means that any tiny leakage in one capacitor will charge the other one into overvoltage

(This can be overcome with equalizing resistors or Zener diodes, but is only effective as long as the current draw of the resistors is higher than the expected worst case leakage, which might be a noticable waste of power)

I would take two motor run capacitors in parallel. One 3uF + 1.5uF. mine ones have both 475V ratings. We also recently ordered a couple proper capacitors at an online lamp supply store in the Netherlands. They still listed them for sale. I need to ask a colleague which site it was exactly…