Air Conditioning - Lennox capacitor

Hi, I wonder if one of you experts could help me out with a capacitor. I have a Lennox hs21-048-1p a/c unit outside. Turned on a/c first time today, I heard air handler in attic running but not getting any cooler, so I looked outside and didn't see fan on outside unit running. Took side panel off and saw the red wire going to capacitor burnt off at capacitor wire terminal. I look in my book and online and I see that this is a dual run capacitor not the big black capacitor that sits next to it which that one is the start capacitor according to my research.
Anyway, all the a/c store are closed for the weekend so I could either buy one online or call around monday but I have two questions. This capacitor looks pretty scraped up and small dent at bottom with a black majic marker written on it saying "3 Ton". It has a sticker on it with TGM 50+5 MFD, now I assume that is the part number I also see 440 VAC 50/60HZ. So if I have my terminology right this unit is a 4ton unit, why is there a 3 ton capacitor in it? Doesn't look original, do I replace this capacitor with the same part number? If not, how am I suppose to guess at what part number was original or to put in here?
My last thing is, I'm not an a/c guy, but I know what a capacitor is or generally does, would it be safe to say, this capacitor blew and fried the terminal end and about an inch of wire off, or would something else of caused it down the line. I don't see anything else fried. I started it up by going to test mode and the low mode kicked on then high mode so, then I shut it off.
Thanks for any help folks.
Russ

By the way, as I'm sitting here reading some capacitor posts from folks in the past, I don't know if the experts allready know this but this capacitor is not the black one it's a shiny round silver one with 3 terminals. Fan, Herm, and either C or O, and it's the C or O termnal wire that fried, the other two terminals are fine besides a little bit of corrosion on them. It's 25 miles from the texas gulf, so bound to be some on there. If some kind of numbers are needed off of motor I could try to find those if you need them. Thanks.

put a new end on the burned off wire and hook it back up. The capacitor may be ok and it was just a loose connection that heated up and burned off Check allthe other electrical connections for tightness while you are at it.

I can certainly do that, is it safe to assume the capacitor is okay for this unit. Just has me a little concerned that it says 3 ton in handwriting on it when it's a 4 ton unit. I had the coil assy replaced last year because they sprung a leak and I think they put this capacitor in it then. Just want to make sure that I am not or haven't damaged the unit by having the wrong capacitor in it. Thanks for any info, I appreciate it much.
Russ

capacitor sizes vary not by tonnage but by the compressor but a 50 is typically larger than a 3 ton you will most of the time see a 35 on a 3 ton so I think you are OK.