Radium metal halide bulbs will not be produced anymore!

[Reefering1]

Well they put the specs in to be followed.
20 mfd 280v 10000AFC CAP.

Why its 300 not the listed 280?
Considering the probable age of these well who knows.
280v listed caps don't seem to be common.
Or 300v for that matter.
Yea general consensus is higher is better than lower.
In this case though you know 120v is max unless you switch the wires on the AC side to 277v. Now a 250v cap def shouldn't be put in.
Don't think this cap is that important anyways, being on the AC side. Think it's just for power factor correction..

And spec is arbitrary, the m80 was not originally designed for these bulbs. It was found to the best fit. Iirc, the imported bulb doesn't use America's ansi standard

 

[oreo54]

I hear you man.. Hamilton assembled the ballasts and went with the york 300v, on every one ive seen, that's all i know. I can open up a pfo and see whats in there tomorrow. and agree 300v doesn't seem to be available. As far as power factor, his ballast works but draws too much power- this is what led me to my recommendation of capacitor

.
I'd be surprised if it was the capacitor since it's sort of optional in that type of ballast.
Thus is similar but a smaller wattage.

 

[oreo54]

And spec is arbitrary, the m80 was not originally designed for these bulbs. It was found to the best fit. Iirc, the imported bulb doesn't use America's ansi standard

It's the design...
HX-HPF
Not too complicated
I sort of implied the cap on the AC side isn't as crucial as if it was on the dc side.

Also why, for fun I' d check where your ac black ( hot) wire is. Therd are 2 choices.

But these are out of my pay grade it's only a guess. Problem is odd

 

[Reefering1]

.
I'd be surprised if it was the capacitor since it's sort of optional in that type of ballast.
Thus is similar but a smaller wattage.

So how does it effect the power factor? And it doesn't say optional on the schematic on the m80's transformer..

 

[PaulErik]

The capacitor for that ballast circuit is only used for power factor correction. That’s what has failed. If the bulb is operating normally but has a higher amperage draw.

The capacitor has to have a minimum rating of 280V. The capacitor is connected to the 277V tap in the ballast. This exposes the cap to that voltage.

 

[oreo54]

The capacitor for that ballast circuit is only used for power factor correction. That’s what has failed. If the bulb is operating normally but has a higher amperage draw.

The capacitor has to have a minimum rating of 280V. The capacitor is connected to the 277V tap in the ballast. This exposes the cap to that voltage.

Even though I stand corrected.. Thanks..
Now how does this cap effect the wattage (Kill a watt ) ?

 

[PaulErik]

On higher wattage HX ballast circuits the capacitor is only correcting the power factor but is required to keep the amp draw lower on the transformer side of the coils.

 

[oreo54]

On higher wattage HX ballast circuits the capacitor is only correcting the power factor but is required to keep the amp draw lower on the transformer side of the coils.

Thanks how does the cap voltage play into this?

 

[PaulErik]

A failed capacitor will cause the autotransformer side to work harder on that ballast.

 

[Reefering1]

The capacitor for that ballast circuit is only used for power factor correction. That’s what has failed. If the bulb is operating normally but has a higher amperage draw.

The capacitor has to have a minimum rating of 280V. The capacitor is connected to the 277V tap in the ballast. This exposes the cap to that voltage.

Your the man!! Thanks for chiming in

 

[PaulErik]

The capacitor voltage rating is just the maximum rated voltage. Using a higher voltage cap won’t change the operation.

 

[oreo54]

A failed capacitor will cause the autotransformer side to work harder on that ballast.

Last one, I promise.. so that makes the cap "optional" i.e with or without it output isn't effected in a meaning-full way.(GENERALLY) .. except to save on your bill.. and in bigger ones not so optional because of heat?

And this is all correct? Oh Advance # just thrown in for scavengers.

 

[Reefering1]

Last one, I promise.. so that makes the cap "optional" i.e with or without it output isn't effected in a meaning-full way.(GENERALLY) .. except to save on your bill.. and in bigger ones not so optional because of heat?

And this is all correct? Oh Advance # just thrown in for scavengers.

He measured 730w and the others @ 330w. If the transformer is working harder I would imagine this will impact lifespan and make it loud. But apparently is still fires the bulb

 

[jackson6745]

He measured 730w and the others @ 330w. If the transformer is working harder I would imagine this will impact lifespan and make it loud. But apparently is still fires the bulb

Yea bulb fired fine for 6 months, light output and spectrum was normal. Looked identical to the ballasts running at 330w. Will be nice to save a few bucks on the electric bill

 

[PaulErik]

That looks correct expect it’s designed for European 100V 3.0A lamps. The actual bulb it was designed for was the original OSRAM HQI-TS and OSRAM HQI-T.

The capacitor is generally optional on certain HX (high reactance autotransformer) ballasts. Mostly on lower wattage and single voltage input ballasts. On the M80 ballast it should always be operational. The autotransformer could potentially burn out permanently from excess heat.

 

[djf91]

I had to replace the capacitors on my 400 watt PFO ballasts. One day I came home to find the one of the bulbs not firing at all. Replaced the capacitor and it worked like new again. I ended replacing the capacitors on the other units and noticed an increase in light output from each bulb. Visibly much brighter.

 

[Reefering1]

I had to replace the capacitors on my 400 watt PFO ballasts. One day I came home to find the one of the bulbs not firing at all. Replaced the capacitor and it worked like new again. I ended replacing the capacitors on the other units and noticed an increase in light output from each bulb. Visibly much brighter.

What ballast is that? I wonder if the cap is on the output side on that one..(?)

 

[PaulErik]

The PFO 400 watt ballasts use a different ballast circuit type (CWA - constant wattage autotransformer). The capacitor is used for both ballasting the bulb and power factor correction. A failing capacitor in that circuit will change the lamp operation. With these types of ballasts it’s a good idea to periodically check the capacitor. Can simply be done with a Kill A Watt meter and checking the power factor or even just by monitoring the line in amps or wattage. The amps and wattage will drop overtime.

 

[PaulErik]

I should add that certain PFO 400 watt HQI ballasts were actually CWI (constant wattage isolated) but they still operate similarly to a CWA.

 

[Reefering1]

The PFO 400 watt ballasts use a different ballast circuit type (CWA - constant wattage autotransformer). The capacitor is used for both ballasting the bulb and power factor correction. A failing capacitor in that circuit will change the lamp operation. With these types of ballasts it’s a good idea to periodically check the capacitor. Can simply be done with a Kill A Watt meter and checking the power factor or even just by monitoring the line in amps or wattage. The amps and wattage will drop overtime.

Is there any advantage to preemptively change the cap on a hx ballast? Or Would I just measure the wattage to calculate the answer?