Id'ing a 150 uF 450V cap

I don't see any info on the ESR rating so is it safe to assume it's not a low ESR?

https://www.electro-tech-online.com/custompdfs/2013/05/pi20134-135.pdf

I don't see anything about the ripple current as well.

The ripple current is in the cart on the right. Don't see any ESR, but many high voltage caps don't have any ESR specs.

Based on the ripple current it looks like a good one.

The ESR can be calculated from the capacitive reactance and the dissipation factor (DF or tan(sigma) ): https://en.wikipedia.org/wiki/Dissipation_factor
The Ripple current rating is on the right hand side of the page you linked to. If you are using a frequency other than 120Hz, then you'll need to use the multipliers listed at the bottom right of the page you referenced.

So in my case can I replace it with something like this? I'm not sure what the frequency is it supplies DC voltage to a ballast so maybe 120 Hz?

https://www.mouser.com/ProductDetai...RGrQpy7VAEtf0nMRAXMFIgEXEg/c1hx/NOpJ1fk0ahA==

I think that one is only 400 volts. How about this one?

https://www.electro-tech-online.com/custompdfs/2013/05/269265314d9b14437542b-219948.pdf

Dougy, I like the calculation but I can't get it to match up with the spec sheet values. There must be some other "stuff" to consider like bond resistance?

Here is an example: calculates 3.9 ohms for a 100 Ufd. @6.3 volts but the spec quotes 5 ohms.

https://www.electro-tech-online.com/custompdfs/2013/05/RVS-5289.pdf

Yes, the calc's don't match the specified ESR values; for the ones I checked, the specified ESR is around 25% higher than the calculated (100uF/22u/6.3V, .22u/1u/10u/50V). I notice the impedance is highly variable with temperature (see impedance ratio); perhaps the DF and ESR are measured at different temperatures, or maybe they just add a fudge factor to allow for worst-case ESR.