I'm cleaning up an old, solar-powered fan that seems to work well, with one intermittent issue that seems related to this component:

20160611_123334 by triangleforge, on Flickr

When I have that in the circuit, the fan cuts off - apparently when the sun is particularly bright and the panel is generating max output. If I delete that from the circuit, it all works just fine.

What is it, and how essential is it to the function of the system? I'm going to wire in a switch so we can turn it on and off, if that makes any difference.

I'd say it's some sort of switch. Can you give me the numbers that are on it?

Looks like it's stamped "K030" and "PN"

It doesn't have any moving parts.

2016-06-11_01-14-56 by triangleforge, on Flickr

I pulled it out and on the bottom, it has "KSD301" in the bakelite. Googled it, and here's my answer:

"KSD301 series Thermostats are widely used for temperature control or overheat protection of various household electric appliances, such as water dispenser, water heater, bread oven, dishwasher, drying machine, disinfection cabinet, microwave oven, electric coffee pot, electric caldron, irons, refrigerator, air conditioner, laminator, office equipment, car seat heater, and so on."

Because it's cutting out so quickly - without the motor showing any apparent strain, or any real overheating in the circuit - I'm guessing it's busted.

...and a further search says it's rated for 30C or 86F.

So maybe it's working fine after all, as it's been a hot June day here in Arizona... Exactly the sort of day & temps when you'd want a fan ON instead of off...

Thanks for the info!

Quote from: triangleforge on June 11, 2016, 06:09:59 PM
So maybe it's working fine after all, as it's been a hot June day here in Arizona... Exactly the sort of day & temps when you'd want a fan ON instead of off...

Thanks for the info!

One would question the purpose of that fan.

Quote from: ducpainter on June 11, 2016, 06:15:09 PM
One would question the purpose of that fan.

Air circulation in a meat locker?

Quote from: howie on June 11, 2016, 09:16:51 PM
Air circulation in a meat locker?

I don't want my meat stored at 86deg F.

Sooo... yet another life lesson in the importance of paying attention. Every time I've messed with trying to troubleshoot this "broken" attic fan, it's been a nice day outside (it's a solar fan, so, duh), breezy, pleasant and, you guessed it, about 85 degrees outside.

All this time, my observation was that the fan cut out when it got too hot because, well, I was standing around in the sun staring at a solar attic fan, getting impatient, and I was getting hotter. Why on earth would you design an attic fan to stop when it gets over 86 degrees? Don't you want it running when it's hot and off when it's cold?

After poking around on HVAC help sites a bit and discovering it's common to have thermostats that kick on at temps ranging from 90 to 120 degrees, I started to question my assumption that I actually knew what was going on - something I should probably be doing most of the time, given my actual track record.

So, yeah. I got out the multi-meter and a heat gun and found out that's exactly what was happening - continuity at hot temperatures (I'm betting somewhere around 86 degrees or so), and an open circuit when it's colder.

You may now return to your regularly scheduled NMC.

Well, not such a bad outcome.

A) You got it sorted.
B) Cost zero dollars.
C)You learned something new.

Win-Win-Win. 

...and you figured it out without butchering the wiring.

I should have realized it was closed at 86^o.

Quote from: howie on June 14, 2016, 01:37:43 PM
I should have realized it was closed at 86^o.

Yeah...me too.

It works just like the fan switch on my pellet stove in the shop.