Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > General Electronics Technical Discussion
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 06-05-2019, 01:04 PM   #1
Dannyx
CertifiedAxhole
 
Dannyx's Avatar
 
Join Date: Aug 2016
City & State: Constanta
My Country: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hardcore Geek
Posts: 2,850
Question Dead hand drier autopsy - motor discussion

Good day folks. A few days ago I had the misfortune to be assigned a hand drier, the vertical type with a slot at the top where you insert your hands and a jet of air on either side blasts away the water. This thing was a nightmare to work on and it's stuff like this that makes me hate my job: very dirty, disgusting ! They didn't even have the courtesy to let it dry before plopping it on my desk....dirty water dripping out of it, mixed with bits of dust, hairs and dirt, limescale everywhere, a pungent moisture smell....horrible experience ! The type of thing you would only give to a greenhorn to work on when you don't feel like doing dirty work...most annoying ! Adding to the frustration was that many of the screws were rusty and stuck in place, so just opening up the thing was not enjoyable in the slightest...

Getting past the ugly nature of the job, the actual problem came down to the motor itself which is far past f***ed (see the picture): moisture got sucked up through the bottom, into the whole machine, causing many of the metal parts to rust, including the impeller blades and part of the motor housing as you can see. The expansion of the rust actually caused the impeller to weld itself to the inside lip of the cover there ! I have no idea how it could've possibly ended up SO bad inside - you wouldn't think leftover water on hands can do this sort of damage, especially since it's (SHOULD BE !) designed to be immune to moisture...it's like they left it out in the rain on purpose just to screw with me...

It's also one of the most overkill and over engineered things I've ever seen...just look at that control board ! Was this really necessary ? It's a hand drier - you just run a motor ! Why do you need a computer in there ?! Amazingly, the board works and was perplexingly the driest part in the whole machine, despite that box just having a POS metal lid with no gasket and no screws whatsoever that was all bent and not fitting properly, because the thing was kicked or knocked somewhere in a bottom corner and a lot of things no longer fit or close properly...*ARRRGHH !! * Stuff like this just made it more and more annoying the more I dug into it and I would love to beat the crap out of that thing with a sledgehammer just because it's such a humongous piece of garbage stinking up my shop and soiling my hands and desk and wasting my time ! !

*RANT OVER*

When I turned it on, I could hear the rising frequency sweep vibrating the motor windings in the audible range, but it quickly shut back down and returned an error code (yeah, it's got a display at the top - did I mention "overkill" ?). I got the motor out and found THAT....game over, since there's no way you're restoring that, not with the rock bottom equipment we have here. Still, the motor's pretty interesting: it's got 8 wires going into it ! 3 fat ones and 5 thinner ones. In the picture of the control box, the first three are the black, white and red in the bottom-left corner and just above that terminal block there's the other 5...what is this motor ? Is it a three phase VFD-driven motor ? Why all the wires then ? There's a bridge rectifier, two large caps, 6 IRFP460 FETs and a handful of other small components, so it must be a VFD....STILL overkill IMO. Would it be possible to find a replacement for such a seemingly dedicated motor ? Swapping it would be a nightmare, since those wires pass through a moulded plug in the housing so I'd have to cut each one then individually solder them back onto the new motor, plus just the idea of working any further on this thing makes me sick...cheers guys
Attached Images
File Type: jpg 20190604_145004.jpg (827.9 KB, 35 views)
File Type: jpg 20190603_144509.jpg (690.0 KB, 34 views)
__________________
Wattevah...
Dannyx is offline   Reply With Quote
Old 06-05-2019, 02:16 PM   #2
Retro-Hipster
Tinkerer
 
Retro-Hipster's Avatar
 
Join Date: Apr 2019
City & State: Salt Lake City
My Country: United States
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 125
Default Re: Dead hand drier autopsy - motor discussion

Nice. LOL

Does the motor have any identifying marks or labels? Also, I might suspect that it is a standard AC motor, but with something like a rotory encoder/an array of hall effect sensors inside. If my guess is correct, you should most likely find all three of the large ones can be ohmed out and have some continuity to each other, but that the other smaller wires would have no connectivity to the big three.. Well, that is my guess anyways.

Could be some sort of starter windings I suppose, but yes. Are those 6 fets on the board in two parallel sets? If so, are two of the 3 wires on that motor connected to the source or drain on the fets? Right now I'm kind of suspecting that the motor is a two pole ac motor. You would have one winding connected to one of the legs of the mains (probably through that relay) and then the other two would be connected to the 2 sets of mosfets. This would create the two phases for the ac motor. Then the 5 other windings would be something like a rotary encoder to give the mcu information on where the motor is so it can sync the phases. An advantage to this would be that you can control the speed/make the device work the same in both 240v 50hz and 120 60hz AC countries I suppose..

And I suppose the last thing I could say is that you may be able to save the blower assembly/motor. You might try grabbing something like a thing of Tupperware and then just submerge the rusted to shit part with some vinegar. (You could also use hydrochloric acid or something commercial like Evaporust. ) You'd be amazed what about 24 hours of white vinegar will do to the rust. haha

That motor kind of looks like the ones you'd find in vacuum cleaners actually...
__________________


“Men always seem to think about their
past before they die, as though they were
frantically searching for proof that they
truly lived.”
– Jet (Cowboy Bebop) -

Last edited by Retro-Hipster; 06-05-2019 at 02:29 PM..
Retro-Hipster is offline   Reply With Quote
Old 06-05-2019, 02:26 PM   #3
Dannyx
CertifiedAxhole
 
Dannyx's Avatar
 
Join Date: Aug 2016
City & State: Constanta
My Country: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hardcore Geek
Posts: 2,850
Thumbs up Re: Dead hand drier autopsy - motor discussion

Quote:
Originally Posted by Retro-Hipster View Post
Does the motor have any identifying marks or labels?
Sadly no, at least not ones that I could use - just an assembly date or something irrelevant.

Quote:
Originally Posted by Retro-Hipster View Post
Also, I might suspect that it is a standard AC motor, but with something like a rotory encoder/an array of hall effect sensors inside.
WHY would it have encoders and the likes ? I too thought of that, but it wouldn't quite make sense...

Quote:
Originally Posted by Retro-Hipster View Post
Are those 6 fets on the board in two parrelel sets?
Don't know - haven't measured them TBH.

Quote:
Originally Posted by Retro-Hipster View Post
And I suppose the last thing I could say is that you may be able to save the blower assembly/motor.
Probably. If it were mine or got it for free for the purpose of installing it at home or something, I would probably put in some elbow grease and would eventually get it going again since it IS pretty expensive indeed when new...this would require a lot of scrubbing, heavy duty detergent, wire brushes, hot running water, clothes I don't mind ruining and an outdoors space to work in...that should just about cut it

Quote:
Originally Posted by Retro-Hipster View Post
That motor kind of looks like the ones you'd find in vacuum cleaners actually...
Correct - I too had hoped it would be a vac motor, just in an extra plastic jacket to make it more water resistant, but what put me off was the multitude of wires. An "universal" async motor like that would only require 2 wires going to it.
Dannyx is offline   Reply With Quote
Old 06-05-2019, 02:52 PM   #4
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,191
Default Re: Dead hand drier autopsy - motor discussion

This might be the motor? http://www.czowo.com/sale-10257912-d...and-dryer.html
It might not be the exact motor but the wiring might be the same
Attached Images
File Type: jpg 8wireMotor.JPG (55.8 KB, 12 views)

Last edited by R_J; 06-05-2019 at 03:37 PM..
R_J is offline   Reply With Quote
Old 06-05-2019, 03:13 PM   #5
Retro-Hipster
Tinkerer
 
Retro-Hipster's Avatar
 
Join Date: Apr 2019
City & State: Salt Lake City
My Country: United States
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 125
Default Re: Dead hand drier autopsy - motor discussion

Every time you post R_J, I am impressed. lol That sure looks like the motor to me. hahaha
Retro-Hipster is offline   Reply With Quote
Old 06-05-2019, 03:27 PM   #6
Retro-Hipster
Tinkerer
 
Retro-Hipster's Avatar
 
Join Date: Apr 2019
City & State: Salt Lake City
My Country: United States
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 125
Default Re: Dead hand drier autopsy - motor discussion

Oh, I noticed that the opening on the blower cage seems a bit different/more narrow on the opening.. Also, I feel silly not thinking it was a brushless dc motor.. ^^;; That just makes more sense. That definitely looks practically identical to me though.
Retro-Hipster is offline   Reply With Quote
Old 06-05-2019, 05:21 PM   #7
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,760
Default Re: Dead hand drier autopsy - motor discussion

AK2006H AIKE hand dryer, from the PCB number.

I don't see an SMPS transformer, so the H-bridge must be using rectified mains voltage.

I wouldn't warranty the repair because of the water and corrosion. It's supposed to have a intake air filter, lol.
redwire is online now   Reply With Quote
Old 06-05-2019, 10:51 PM   #8
Dannyx
CertifiedAxhole
 
Dannyx's Avatar
 
Join Date: Aug 2016
City & State: Constanta
My Country: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hardcore Geek
Posts: 2,850
Talking Re: Dead hand drier autopsy - motor discussion

Quote:
Originally Posted by redwire View Post
AK2006H AIKE hand dryer, from the PCB number.
It's actually a "Jofel" but no doubt could be rebranded under many other names whilst still using the same chassis and parts.

Quote:
Originally Posted by redwire View Post
I don't see an SMPS transformer, so the H-bridge must be using rectified mains voltage.
Correct. There IS a small SMPS there for various signals and stuff, but it's driven from a separate small transformer, tucked under that bundle of wires coming into the control box. You can just about see the yellow top there.

Quote:
Originally Posted by redwire View Post
It's supposed to have a intake air filter, lol.
It does - all clogged and dirty and sopping wet

The motor, although similar in concept, is unlikely to be an exact match.
Dannyx is offline   Reply With Quote
Old 06-06-2019, 03:40 AM   #9
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 22,902
Default Re: Dead hand drier autopsy - motor discussion

is it a Dyson Air-Blade???

you could strip the motor, shotblast the rust off and replace the bearings - if you worked somewhere else!
stj is offline   Reply With Quote
Old 06-06-2019, 07:53 AM   #10
Dannyx
CertifiedAxhole
 
Dannyx's Avatar
 
Join Date: Aug 2016
City & State: Constanta
My Country: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hardcore Geek
Posts: 2,850
Unhappy Re: Dead hand drier autopsy - motor discussion

Quote:
Originally Posted by stj View Post
is it a Dyson Air-Blade???
Nope - a "Jofel" like I said, though yes - the concept is the same as that one. We have those Dysons in one of our malls here

Quote:
Originally Posted by stj View Post
you could strip the motor, shotblast the rust off and replace the bearings - if you worked somewhere else!
True - a job is made a thousand times less appealing when you realise you have insufficient tools and work for a place that doesn't give a damn. If I had proper tools and work conditions, I would be able to tackle even the dirtiest of jobs with enjoyment....*SIGH*
Dannyx is offline   Reply With Quote
Old 06-06-2019, 09:22 AM   #11
diif
Badcaps Veteran
 
Join Date: Feb 2014
City & State: Midlands
My Country: England
I'm a: Professional Tech
Posts: 4,838
Default Re: Dead hand drier autopsy - motor discussion

redwire got it, Aike are OEM/ODM manafacturers and according to their website make 40% of the worlds hand dryers. I would think their motors are fairly universal.
diif is online now   Reply With Quote
Old 06-06-2019, 12:28 PM   #12
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,760
Default Re: Dead hand drier autopsy - motor discussion

Rusty brushless motors, I find the magnets and hall sensors can get covered in iron dust and not work. The hall sensor does not get good flux signal.
Use sticky masking tape to clean that up.

spelling is "dryer" not "drier" so searches might be giving bad results.
I wonder what the hand dryer seller would charge for the same repair, a new motor seems hard to find.
redwire is online now   Reply With Quote
Old 06-06-2019, 01:32 PM   #13
Dannyx
CertifiedAxhole
 
Dannyx's Avatar
 
Join Date: Aug 2016
City & State: Constanta
My Country: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hardcore Geek
Posts: 2,850
Red face Re: Dead hand drier autopsy - motor discussion

Quote:
Originally Posted by redwire View Post
spelling is "dryer" not "drier"
Pfft....yeah, epic fail for someone who has a degree in this sort of stuff >_> Hey, I'm only human - I'm allowed a "your vs. you're" every now and then
Dannyx is offline   Reply With Quote
Old 06-06-2019, 08:18 PM   #14
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,760
Default Re: Dead hand drier autopsy - motor discussion

I mention it only to help search for a motor. Once you have the keyword, it's easy to find things but man, spell it wrong and no hits.
redwire is online now   Reply With Quote
Old 06-06-2019, 08:49 PM   #15
kaboom
"Oh, Grouchy!"
 
kaboom's Avatar
 
Join Date: Jan 2011
City & State: PA
My Country: USA
I'm a: Professional Tech
Posts: 2,254
Default Re: Dead hand drier autopsy - motor discussion

Quote:
Originally Posted by redwire View Post
Rusty brushless motors, I find the magnets and hall sensors can get covered in iron dust and not work. The hall sensor does not get good flux signal.
Use sticky masking tape to clean that up.
Just like pickup coils for automotive ABS "speed sensors."




Quote:
Originally Posted by redwire View Post
spelling is "dryer" not "drier" so searches might be giving bad results.
I wonder what the hand dryer seller would charge for the same repair, a new motor seems hard to find.
White vinegar, heated near boiling, does a great job on limescale and is not like handling hydrochloric acid.

Dannyx, put some in a glass container (pickle jar?) & heat in a microwave oven. Try to soak/pour it over the nut holding the impeller.
If there's enough slack in the wires, immerse the entire volute/impeller assembly in hot vinegar.
The round volute/cone thing enclosing the impeller should eventually pry off the baseplate/static vanes, if it's anything like a vacuum motor.

My temptation would be to EOL it. Good luck.
__________________
"pokemon go... to hell!"

EOL it...

Quote:
Originally Posted by smashstuff30
guilty,guilty,guilty,guilty!
guilty of being cheap-made!
kaboom is offline   Reply With Quote
Old 06-16-2019, 06:25 AM   #16
Dannyx
CertifiedAxhole
 
Dannyx's Avatar
 
Join Date: Aug 2016
City & State: Constanta
My Country: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hardcore Geek
Posts: 2,850
Default Re: Dead hand drier autopsy - motor discussion

Update: my dear ol' colleague apparently wanted to give it a shot, since I saw it strewn all over his bench the other day...as if there wasn't enough stuff on there already Knowing the ol' fart, he will scrub that rust with his fingernails, he will use his own toothbrush on it, he will even sleep with the thing at night....anything to show off, rub it in my face and prove that he's better than me. I often do this sort of stuff on purpose: leave stuff I don't want to bother with for him to struggle with
Dannyx is offline   Reply With Quote
Old 06-16-2019, 12:24 PM   #17
seanc
Badcaps Veteran
 
Join Date: Nov 2008
City & State: Cambridge, UK
Line Voltage: 220V 50hz
I'm a: Hobbyist Tech
Posts: 1,283
Default Re: Dead hand drier autopsy - motor discussion

http://aikehanddryer.sell.everychina...and-dryer.html
seanc is offline   Reply With Quote
Old 06-16-2019, 12:26 PM   #18
Dannyx
CertifiedAxhole
 
Dannyx's Avatar
 
Join Date: Aug 2016
City & State: Constanta
My Country: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hardcore Geek
Posts: 2,850
Default Re: Dead hand drier autopsy - motor discussion

Yeah, that's the one.
Dannyx is offline   Reply With Quote
Old 06-16-2019, 01:48 PM   #19
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,760
Default Re: Dead hand drier autopsy - motor discussion

It needs a new blower motor and all that labour to try fix it- it won't make any warranty period and end up being back in the shop soon.
I liked it when other techs took over on a repair job. I would play dumb, like I don't know what's wrong or how to fix it.
Supertech would take the work, blame me for all the things that were wrong, every missing screw. But it's his baby now
redwire is online now   Reply With Quote
Old 06-16-2019, 01:50 PM   #20
Dannyx
CertifiedAxhole
 
Dannyx's Avatar
 
Join Date: Aug 2016
City & State: Constanta
My Country: Romania
Line Voltage: 230VAC 50Hz
I'm a: Hardcore Geek
Posts: 2,850
Default Re: Dead hand drier autopsy - motor discussion

Right, right and right some more !
Dannyx is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums © 2003 - 2020
Powered by vBulletin ®
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 01:51 PM.
Did you find this forum helpful?