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> Ac Motor Schizophrenia.
Jimthecopierwrench
Posted: June 15, 2017 06:48 pm
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And so I have this cheap desk fan (that IIRC was pulled out of the trash)

Sometimes I turn it on and have to give the blades a bit of a push before it comes to life (I had originally thought it had dirty/seized bushings - yet unpowered, it spins freely)

Sometimes it won't start at all - the blades show clear resistance to turning, sometimes they spin up slowly and stop again.

But it also changes speed sometimes. It will be spinning away and then slow down by some 20-30 percent, run that way for awhile, and speed up again.

As far as I knew, AC motors couldn't do that .. whatcha think might be going on?


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Sch3mat1c
Posted: June 15, 2017 07:59 pm
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Huh, some kind of induction motor I guess. Frayed connections to the windings?

If it's shaded-pole, maybe the shade corroded open or something?

Tim


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Nothing40
Posted: June 15, 2017 09:45 pm
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Perhaps (intermittent) shorted windings?
Do you have an easy way to monitor current draw,to see if it changes?


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MacFromOK
Posted: June 15, 2017 10:21 pm
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Could be varnish buildup on bushings or whatever provides thrust control. I've had 'em appear ok until the blade puts some thrust on the shaft (sometimes they try to stick there).

If it has steel bushings, the shaft may be galled and require sanding (if so, it won't last long because the impregnated oil in the bushings is gone). If bronze, oiling usually does the trick. I generally use ATF for fans.

Good to hear from ya Jim. smile.gif


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Jimthecopierwrench
Posted: June 15, 2017 11:58 pm
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QUOTE
Good to hear from ya Jim. smile.gif
, thanks .. wish i had some good news to share.

The suggestions posed might explain some of the oddball behavior, but when the unit picks "some" speed - it remains stable.


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MacFromOK
Posted: June 16, 2017 12:32 am
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Multi-speed or just on/off?

If multi, I'd check the switch. Otherwise I agree with the other guys, probably something hinky in the windings (or maybe a flaky cap?). dunno.gif


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AwesomeMatt
Posted: June 17, 2017 06:25 pm
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Crusty bearing that is only occasionally crusty?

Wire that is cracked and corroded part way through, makes occasional contact with the larger part of it through the corrosion, depending on heat and other things?

In other news, one thread's as good as another, what's been on with you?
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Jimthecopierwrench
Posted: June 17, 2017 08:39 pm
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QUOTE
what's been on with you?


Sadly nothing good .. in the heap again, went out to celebrate my 50th and a couple - 3 actually - East Hammer clowns thought robbing me would be a stellar idea. I uh .. "declined" in typically polite Irish manner - up on assaults and threatening death. All lawyered up again. Feck.

No real bail restrictions this time though, and my licence isn't in jeopardy .. so at the worst I'll do a few months late next year, though the mouthpiece doesn't seem too concerned about it and this guy is charging me 1/4 what the last guy did.

I offered to take 30 days on the spot but they want 3-4 months.

So .. yeah.

Still set on having a bus. Really want a Bluebird TC2000FE 78 passenger - all the room I'll ever need. Solar, wood stove, genny - small shop, benches, mill.

A bit concerned a 19K pound 40 foot bus is a bit much for a 5.9 cummins/A5454 Allison, but they seem to hold up. I've heard from the skoolies they'll cruise at 60, and if nothing else parts should be relatively cheap and easy to come by.

As well, the gal and I have been looking at farms 3-4 hours out of town - 50 acre range - where the plan is that for the time being I'd work 4 days and take 3 off, build a nice shop, etc.

Beyond that, got a fourth dag with the gal a few weeks ago - 12 y.o. retired mushing lead dog. He's nice but so out of his environment - akin to an alien abduction really - that he's still wandering around wondering what that thing was the grays just stuck up his arse. Never been in a house, on a bed, etc..

Not too much else .. can't get my truck to run quite right and it's been quite the head scratcher .. might toss a thread in here to see if anyone can figure something I've missed.

since we've derailed the hell out of this thread anyway..

Been meaning to ask Tommy - any chance of sending along a tin of Surströmming? Nutter Jimbo is up for the challenge wink.gif .


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AwesomeMatt
Posted: June 17, 2017 11:26 pm
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Why a bluebird schoolie and not a city bus?

I wouldn't worry about engines, you'll probably converting it to electric soon anyway. I'm starting to hop on the solar/self-driving/battery bandwagon. People are figuring we're 3-5 years away from things rapidly tumbling into place.

https://www.youtube.com/watch?v=2b3ttqYDwF0 <-- I found this pretty interesting.
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Jimthecopierwrench
Posted: June 18, 2017 02:09 pm
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QUOTE
Why a bluebird schoolie and not a city bus?
Skoolies are steel bodies on medium duty (26000 GRVW) conventional chassis - easier and cheaper to service - or even repower, easier to mod, etc. especially chassis. (if I wanted .. and I drool at the thought - a 4x4, it would be a matter of picking up an old Rockwell military truck for bits behind the bellhousing) Cities are typically one off (mfgr) designs - ie, the fishbowls and fliers monococque aluminum, reverse mounted offset 6-71's, oddball suspensions, etc. As well, skoolies are retired on schedule, some with reasonable hours/mileage - cities when there's nothing left of them.

(I used to tow refurb Gm New Flyers from Toronto to Ottawa - lots of opportunity to chat with the mechanics, and gander at the dumpster)

Common skoolie engines are Cummins 5.9, T444e (7.3 Powerstroke), or DT466 - the latter an excellent engine pre maxxforce branding - can be rebuilt in chassis for ~$2K .. The two former now easy to find at the boneyard if I need stuff like sensors, injectors,. HPOP bits, etc. The 5.9 easily serviceable in most chassis .. for that matter lots of future tuning or modern updates. Cities, well i don't know now. A lot run natural gas and the like ..

Many of these reasons true for highway coaches too.

Although not always true, many cities are spec'd with gearing far too tall for the highway.

In short, cheaper and easier to acquire and maintain.


Well, it's possible in coming years I guess, but for now electric isn't piquing my interest.


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AwesomeMatt
Posted: June 18, 2017 11:03 pm
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Hrm. Interesting. I'd love to build something similar as my own personal FuckOffMobile.

https://www.youtube.com/watch?v=Vh_d31rWt2o <-- I liked this one too, surplus military trucks are apparently dirt cheap. Must be hell for parts though.
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dmg
Posted: June 19, 2017 12:01 pm
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tatra 813 quad axle truck was pretty mutch a common sight for those who built adventure trucks.. those are built like tanks. can carry a lot, decent fuel economy and 4 axles mean load distribution is allso verry good. turns well, runs well, offroad is no problem at all.
maintanance free most of the time, but i'm not sure you can find them in canada or the usa.
they are not civil variants of military trucks, they are the military trucks as they are.
you get exactly what the military gets. older ones are naturally aspirated air cooled engines, if you got the time it will take you to the mars and back without any problem regardless of age.
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AwesomeMatt
Posted: July 10, 2017 07:24 pm
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http://imgur.com/a/sJOcN <-- Saw this, thought of you.

Also...

https://www.reddit.com/r/vandwellers/ <-- Bottomless trove of things like this.
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