Now THIS is a bad cap!

[Hemingray]

Pulled from a Holmes "Blizzard" fan (Model HAPF622R). Fan would not power on whatsoever. Replaced this one cap and it's runnin nicely now.

Never seen a cap of this type fail in THIS way before

[Toasty]

Re: Now THIS is a bad cap!

See those type of failures in wall light dimmers when "standard" CFL's are used instead of incandescent. Or when used for any inductive load such as a fan. Probably caused by poor circuit design with that models "Breeze Modes". Install a 600 volt cap if you can.

[Hemingray]

Re: Now THIS is a bad cap!

Will do, have a similar cap in there for now, ordered some 630V caps though.

[Toasty]

Re: Now THIS is a bad cap!

[b700029]

Re: Now THIS is a bad cap!

What's the glob of stuff coming out? Melted aluminium?

[Toasty]

Re: Now THIS is a bad cap!

Yes. Metallized polyester/polypropylene film capacitor. Difficult to tell but polypropylene is generally suggested for high current AC work.

Metallized polystyrene is not seen too much anymore and was usually a high-stability capacitor. Used a lot in instrumentation and radio where drift needed to be minimized. Could be had down to 1% tolerance. Recognizable (usually) as a clear axial or radial plastic cap that you can see the foil through.

"Plastic film capacitors are insulated with polyester, polypropylene, polystyrene or other dielectric materials.
Polyester film capacitors offer a high dielectric constant and high dielectric strength.
Metallized polyester film capacitors provide excellent self-healing properties, allowing capacitors to withstand high-pulsed voltages without breaking the dielectric.
Polypropylene film capacitors provide very low loss, low dielectric absorption, and high dielectric strength. They also offer very high insulation resistance and negative temperature coefficient.
Polystyrene film capacitors provide extremely low losses, low dielectric absorption, good long-term stability, very high insulation resistance and a small negative temperature coefficient."

Source: http://www.jbcapacitors.com/

That's as good an explanation as I've ever heard.

.

[TheLaw]

Re: Now THIS is a bad cap!

Polyester seems to be good for lower voltages. Polyproplene is usually regarded as better "quality" and is more stable and can withstand more abuse.

[watchmaker]

Re: Now THIS is a bad cap!

I've replaced three such caps in Maxus lamps...

[Hemingray]

Re: Now THIS is a bad cap!

new 630V caps arrived today (5 of them), one installed into the fan, all's well now, even runs off my inverters nicely, so I can use this little fella in my van when needed

[Toasty]

Re: Now THIS is a bad cap!

Excellent!

In your van?? Is this running off an inverter?

[Hemingray]

Re: Now THIS is a bad cap!

Yeah. Does well from it too.

[Toasty]

Re: Now THIS is a bad cap!

Ahhh! Probably what blew the first one. Inverters are notorious for "dirty" power.

[Hemingray]

Re: Now THIS is a bad cap!

Not all too sure, it was given to me for free, bad cap and all.

[Toasty]

Re: Now THIS is a bad cap!

Ok. Thought it blew out on you. Mind the spikes from inverters. Does the same damage as I spoke of re: CFL on standard dimmer.

[Hemingray]

Re: Now THIS is a bad cap!

Ran it for an hour or so off of a Harbor Freight 750W inverter today at a parade, no ill effects. Kept me cool on a warm day while watchin.

[Toasty]

Re: Now THIS is a bad cap!

That's good to hear. Best of luck with it!