I'm repairing my MPP Solar 3kW inverter and charge controller. One of the small caps from the power supply burst and took a diode with it. No problem, all through hole parts. But having a poke around to see if any other components suffered damage I found that the plastic top of one of the big 1200uF 300V capacitors was 'flexible', so I though while I'm here I'll change it to be on the safe side. But this capacitor has three pins, which I've never seen before.
The capacitor is a Jianghai brand CD293, here's the datasheet.
https://jianghai-europe.com/wp-content/uploads/JE25_CD_293_BZ.pdf
So my question is, why 3 pins, when both negative pins are internally joined and the two negative pins are both soldered to the ground plane?
I can't find a direct replacement with Mouser so can I just replace it with the more readily available two pin electrolytic?

 

Extra pins are there for physical support on the PCB.
Yes, you can use the 2-pin capacitor.

 

And also to stop you connecting it back-to-front!

 

Thanks all.