Hello all!
About eight years ago, the run cap in my outdoor A/C unit failed; replacing it made it work fine for at least a few more years, until I moved out of that house.
I found the dead cap while cleaning some stuff up, so I took some pictures of it before tossing it. Maybe these will help someone recognize a bad cap someday.
Matt Roberds
Matt, most capacitors like that are designed to disconnect when the top bulges like that. It's another safety feature that can prevent a little explosion. ^_^
TDD
With all those disclaimers. You're an attorney?
Funny you mention it. I had one fail exactly like that a couple months ago, same size, brand and everything. Bad batch?
No not a bad batch, just a built-in safety feature.
I often had to replace caps in ferro-resonant industrial battery chargers and back 35 years ago they'd explode...and worse still they were the toxic PCB type!
Cool pictures. Thanks for posting. It's stuff like this that makes usenet worthwhile. Cheers, Eric
Me and my late friend GB did a lot of work for rural customers on their HVAC units and the failure rate for the capacitors dropped to zero when we started installing surge arresters directly on the outdoor condensing units. ^_^
TDD
This old Trane is at end of life. I believe I will take your advice on my new one..
The newer units also have a lot of electronic controls that power surges can damage. I modified a lot of contractor grade AC units with anti short cycle timers and high and low pressure cutouts to protect the compressors. Most electronic thermostats have a compressor time delay designed in which may have to be programmed. I used a lot of the Square-D and Supco surge arresters because they're of a fairly high quality. In extreme circumstances, I would drive a 4' ground rod next to the unit and run a #6 bare copper to the internal ground lug along with the existing ground conductor. Remember, it's not just the outdoor unit that needs a surge arrester. The new furnace/air handler units have a lot of electronics including electronically controlled variable speed blower motors. All of the new whizzbang modern energy saving electronic controls are very expensive to replace when a power surge gets by the tiny little MOV's on the circuit board. ^_^
TDD
I already have an 8' rod next to the machine and surge protection at the service. I to think I will throw a protector in the disconnect tho. It can't hurt. There is a delay timer on the machine too,
Was that cost effective? How much does a surge arrester cost, compared to a run cap?
My cost for a dual capacitor is probably $14.00, the cost of a rural service call is at least $100.00, a compressor $800.00. Figure it out. ^_^
TDD
Just have to decide if I want to use pi R squared H, or E equals MC squared, or E equals IR.
Looking back, I see that you didn't answer my question.
Geez! A hard wired Supco SCM150 Surge Protector is around $40.00. It will prevent multiple service calls and thousands of dollars in damages. Dual start/run capacitor $16.00. What does down time cost? I know an ass who refuses to install surge arresters because he want's gear to be damaged by lightning and power surges. He can't understand that one big storm will knock out a lot of equipment when he's tied up on a job on the other side of the state and can't get to those folks thus losing those customers to someone else. ^_^
TDD
Thanks, that is a lot more clear, now.
Was GB from NC near Ashville?
Naaa, right here in Alabamastan. ^_^
TDD
Mine failed this fall, but it didn't bulge like that. A multi meter helped me diagnose the problem.
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