HVAC capacitor questions

Not sure which quality is better. But ... methinks ... this time you should buy _two_ sets so that when it goes kablouie on a hot Friday night the missus ain't gonna be unhappy. Then you could walk out there, fix it in minutes, and be the family hero :-)

Note to self: Got to buy spare float valve for evap cooler. Same reason.

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Regards, Joerg

http://www.analogconsultants.com/

Yeah, always buy two of anything that breaks.

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John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

That is the plan. Being the perpetual cheapo I fond something that will satisfy the cheapo in me and get the redundancy I need for next time.

I going the easy route and getting the dual Genteq tomorrow for ~$35 then trying this guy as a backup

I tool a look at QE Quality capacitors website and it look pretty decent. Assuming its all true.

Not bad for a backup to allow me to get through a weekend before I get a new replacement.

Obvious answer.. don't be the cheapo, buy a real film cap that'll last ten years. It won't even cost ten times more!

Tim

-- Deep Friar: a very philosophical monk. Website:

Suggestions? What is a real film cap? Are you talking about the black plastic bricks with the cap potted inside

I have wondered about the internal construction of metal packaged A/C caps vs the potted film run capacitors. The metal can ones are sometimes referred to as film as well.

I wondered if it wise to use these with an outside A/C unit.

My understanding is that the traditional metal can A/C caps are built that way so when they fail the tops bulge out and break the electrical connections inside thereby isolating the fault.

Would those black plastic ones just catch on fire when hooked to a 40A circuit?

Those run caps seem to fail when it's the hottest outside. That makes sense.

It's a scorcher here right now. Full sunlight, no fog, 67 F. We don't have AC.

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John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

Can't you remodel it to use an inverter? When I had to replace our central ventilation unit I choose a model with an inverter. I replaced the capacitors on the previous one several times.

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
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'Dayton' is Grainger's house brand. Seperate caps are OK< if you have room for thmem. I would just buy the OEM part and a spare.

AFAIK, film caps (the film-in-oil, metal can type) last essentially forever. I don't know about 40A, but I'd be surprised if a film cap operated at 140F ambient didn't last more than 20 years.

The small physical size suggests to me that, at least the start section, is a bipolar electrolytic, which is typically used for motor-start applications, and short lived (not only at the >40A surge, but even just being at 140F ambient for a few years).

The 30uF 370V can I've got sitting in my junk box is about 1-1/4" thick,

2-1/2" wide (oval shape) and 4" tall. Unless they've really changed the game with film thickness these days, I don't see 60uF 440V fitting in a much smaller package unless it's electrolytic. (The run part might still be film though.)

Obviously, you'd need the space to fit such a capacitor...

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

It was damn cold on Saturday even deep inland in the bay area. I was in Livermore freezing in the sub-70 deg F weather. Brrrr!

When I see those tubby nudists in the fog on Baker Beach, I have to say WTF.

I never heard of an inverter in an air conditioner, but the wiki seems to make sense:

I suspect the air conditioning itself is better since it is a continuous flow versus duty cycle modulation. [There are some high end refrigerators that run continuously with what I guess is a similar scheme.]

Those AC caps fail a lot. I know quiet a few Ca to Nv transplants, and they are routinely replacing the AC cap. Since an air conditioner really only lasts about 15 years, it would be wise to go inverter for the replacement. I assume heat pumps have similar schemes.

Something like these? Price isn't too bad.

Yes, and many others; I believe mine are old (not PCBs-old) GE parts (which I guess are Genteq or something now).

Tim

-- Deep Friar: a very philosophical monk. Website:

Just realized I got snookered by Grainger. They labeled the cap Genteq when actually they are Proline. Both made by the same manufacturer that makes GE but the lifetime spec on the Genteq is 60K hours while the lifetime spec on the Proline is 10K hours. :(

Let see, 8700 hours in a year... Houston tx,..figure 5000 hours a year run time... 2 years before I can expect this guy to pop IF it meets its specifications. Genteqs sell for the same price ~$35 on other places besides Grainger.

Oh well. I have my $11 china cheapo (Qe Quality) will be arriving Friday as a backup. Next purchase will be something like the CDE caps. At least a known name in the capacitor business.

No, it's not that bad. This is a STARTING capacitor, not a run capacitor; it gets ten seconds of use four times a day.

In unrelated news, the pressure life of an artillery barrel is about four seconds...

gets

Nope.. That's a run cap. A start cap would be the type used with a hard start kit. The caps they make these days are cheap and don't last. Even the better brands are pretty much junk these days. One thing I would do is use 440v rated caps vs 370v. I think they tend to last a bit longer before going kaput.

it gets

He stated: Dual 60uF/5uF 440VAC in the original post. The 60uF is the starting cap, the 5uF is the run cap.

Nope... The 60 mf is the run cap for the compressor. The 5 mf is the run cap for the fan motor.

Did he say that?