"I am trying to determine if the capacitor failed"
Without a doubt.

"Has anyone ever seen one fry this bad? "
Yes,more than one actualy.

OK thanks for the info, klem1.
I am hoping that there isn't something wrong with the compressor that caused the capacitor to fail. In your experience, have you seen the compressor cause this type of failure?

The unit is only 5 years old.

Thanks for the info.

Mike

I wonder if Trane is using the cheaper start/run capacitors made in China. Last time I replaced one of mine, I went to Granger Supply and found that they had two brands, a cheap one made in China and a more expensive one made In Mexico. I chose the latter. By the way, it cost about $7.50. The price quoted by the dealer service rep was over $100 (for the part).

If the capacitor failed, then I would expect to the can to be swollen or even explode. The can in this picture doesn't seem to be deformed. The burnt and melted wire suggest that a lot of current was flowing but not through the capacitor.

It looks like the leads on top were shorted. Maybe an animal crawled inside and caused the short.

Looking at the rust on the cap,I believe the connection coroded causing a high resistane ( very common occurance on electrical exposed to the elements). The resistance literly tuned the metal and wire red. As already stated,caps are very cheap so just go ahead and replace it.
Here's pointers to help you out. Draw a diagram of the wire connectios paying close attention to markings on cap that say (compressor) and ( fan). That is a dual cap. Take it with you. You can ask but there is little chance they have one. Buy 2 caps,one for each value. Don't freak if they want to sell you a 10% higher mfd or 440 volt where yours is 330,it will work fine. While you are there buy some high heat wire terminals ( see the 2 slots in the old terminals?) You will need to build a simple jumper with 2 caps,be sure to us large enough wire. The terminals must be perfectly CLAMPED TIGHT on wires or the same problem will return eventualy. Good luck.

Great thanks for the info everyone.
I was able to get the dual capacitor at US Supply today. It is a lot smaller, but we double checked, and the numbers are all the same. I also bought a metal pipe strap that can mount it.

Another question:

The top of my old capacitor is too rusted to read what's what on top.

Can you tell by the color of the wires which is the Common, fan and herm?

The burned up wire was orange.

Thanks all.

There should be a diagram glued on the panel you removed to get at the cap. Double check on there but it appears Brown= fan Red And Purple= common Orange=herm
You can also follow the wires from cap back to (A)compressor(herm) (B) fan , likly 2 wires (C) contactor (common)
Pop the wire cover on compressor to make sure connections are clean and tight.

Thanks klem1,

I did find a wiring diagram that confirmed everything. It was the same as you posted yesterday.

I hooked up the new cap last night, tightened all the wire terminals so they slid on tight, and put on a new high heat terminal on the compressor wire. It started up and ran perfect.

It was drawing 9.5 amps per leg at the compressor.

I believe it is a 4 ton unit.

I'm pretty sure it drew the same when I checked it out of curiosity a year ago. Does that sound right? Seems low.
The outside air temp was around 68 degrees.

Thanks again.

Mike Angelini

That does sound low for a 4 ton even under light load but if it cools when weather warms up,don't look a gift horse in the mouth,or get your meter checked.LOL

1st , that's a run capacitor....make sure you match the values that your system calls for...an expensive , very well made capacitor is only about $30 - for the largest size.

2nd , Trane does not use 'Made in China' capacitors - they used GE Industrial , which is now Genteq. Grainger (Dayton) are made in China typically and these capacitors are not built or held to any RoHS type compliance or EIA Specification...steer clear of them.