Jem
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Post by Jem on Aug 11, 2020 13:19:13 GMT
Not bike related - I have looked all over Google for an answer but nothing coming up, so asking here is my final port of call.
My cooker extraction fan gave up a while back. The light still works ,so I know power is going in, as fan and light draw from same AC source.
My questions are- 1) does the motor for the fan have brushes? (If so, I can't see them - I thought maybe they had worn down.)
Could the fan switch have gone ? Although it doesn't seem to have any parts that might break, it's just a piece of hard plastic with some connectors on the back
Or any other suggestions to try?
I've cleaned it and checked all connections.
I hate being beaten by something that might be fixable
ps I would just bench test the fan , but it has 4 wires coming out, a white, a grey a blue and a black....I'm not sure which ones to wire up to test.
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Post by cusqueno on Aug 11, 2020 15:30:28 GMT
I've not had this problem (touching wood) but a quick google suggested that grease build-up might bring the fan to a halt. This seems likely - the solution suggested was to clean it up using *WD40*. That would be worth a try and couldn't hurt - apart from giving the kitchen that smell. Another YouTube video showed a faulty soldered joint on the circuit board behind the switches.
I don't think that the motor will have brushes - it's more likely to be an induction motor. The four wires might be to do with the different speeds you can set the fan at. If it is an induction motor it might have a capacitor associated with it - metal or plastic cylinder probably about 30mm x 16mm dia, with two wires coming out of it / soldered to it. These are easy and cheap to replace if you can work out what value it is.
I've just had a look at the extractor fan over our cooker, but the motor &c is well hidden away and the filter is greasy as hell.
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Jem
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Post by Jem on Aug 11, 2020 19:15:21 GMT
Many thanks for tips. I can't find any capacitor though. It is greasy in there!
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rodh
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Post by rodh on Aug 11, 2020 23:35:47 GMT
4 wires usually means multi-speed ... are you saying that no switch positions work?
These motors are usually induction motors so have almost no starting torque (and no brushes) ...
does the fan spin easily when not powered? If not, try to free it up and try again.
Usually a stalled motor hums slightly when powered ... is yours complerely silent?
This suggests no power or an open coil; do you have a DVM to check resistances, and voltages?
I have seen wiring diagrams hidden inside the housing near the model/serial plate. You might be lucky,
or you might even find the wiring diagram or user/service manual on the web if you know the model.
Hope this helps,
Rod
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Jem
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Post by Jem on Aug 12, 2020 7:39:04 GMT
4 wires usually means multi-speed ... are you saying that no switch positions work? These motors are usually induction motors so have almost no starting torque (and no brushes) ... does the fan spin easily when not powered? If not, try to free it up and try again. Usually a stalled motor hums slightly when powered ... is yours complerely silent? This suggests no power or an open coil; do you have a DVM to check resistances, and voltages? I have seen wiring diagrams hidden inside the housing near the model/serial plate. You might be lucky, or you might even find the wiring diagram or user/service manual on the web if you know the model. Hope this helps, Rod Hi Rod - no sound/movement at all. I've got a multi-meter and have a reading across some combinations of the wires. I will hunt for the wiring diagram, but if I found it, I might need help de-coding it as I am pretty ignorant in most electrical matters. Thanks for ideas Rod Jem |
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Post by oldroadietehachapi on Aug 12, 2020 7:50:32 GMT
What I know about electricity, I learned from Jiminy Cricket.
Cheers Jim
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Post by cusqueno on Aug 12, 2020 8:09:32 GMT
Perhaps post some photos? Maybe that would stimulate the forum’s hive brain.
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Jem
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Post by Jem on Aug 12, 2020 8:21:34 GMT
Perhaps post some photos? Maybe that would stimulate the forum’s hive brain. Good idea, I will - I have the switch arriving tomorrow, which didn't cost much - if that doesn't work then I am open to ideas. Just done some research and the motor costs the same as a whole new hood. So, I know which direction I will go in next. |
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Jem
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Post by Jem on Aug 15, 2020 15:07:57 GMT
Ok, update on this - switch arrived and fitted. Still no movement from fan.
Took fan off and cleaned spindle. Then took fan to the table to test it by wiring it up to mains power. I tried various combinations of the grey, white, black and blue wires and found that the black and white were the live and neutral. Fan started up.....I moved the cable when I went to turn off the power, and my temporary cable crimps came loose and it shorted, sparked and blew the trip switch in the box.
Wired everything back up, but firmer, and the fan is now dead. I have no way of knowing if the cleaning of the fan freed it up or if there is an issue somewhere else in the hood , so I went-on line and found the cheapest complete integrated hood, filter and fittings. It's cheaper than a new motor. (I can also return switch now) £62 free delivery
Thanks for your suggestions and help! Frustrated that I got somewhere, but then messed it up with some sloppy crimping - lesson learned.
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Post by wheelson on Aug 15, 2020 19:05:37 GMT
Likely you did not damage the motor during the shorting episode. Sometimes there is a small thermal fuse that is supposed to reset (but doesn't always) buried in there somewhere. I replaced two of those in our clothes dryer before I found that the main heating element coils were partially shorted, causing the system to overheat and kill the thermal fuses.
Don't feel bad, I have degrees in both electrical and electronics engineering and, without a good schematic diagram, appliance repair is almost always a hopeless cause. I've found that doing an online search will sometimes yield a schematic, tips, even a video. You usually need detailed ID, like the model number of the appliance.
Best,
John "wheelson"
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Jem
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Post by Jem on Aug 16, 2020 8:00:23 GMT
Likely you did not damage the motor during the shorting episode. Sometimes there is a small thermal fuse that is supposed to reset (but doesn't always) buried in there somewhere. I replaced two of those in our clothes dryer before I found that the main heating element coils were partially shorted, causing the system to overheat and kill the thermal fuses. Don't feel bad, I have degrees in both electrical and electronics engineering and, without a good schematic diagram, appliance repair is almost always a hopeless cause. I've found that doing an online search will sometimes yield a schematic, tips, even a video. You usually need detailed ID, like the model number of the appliance. Best, John "wheelson" Thanks John. I might pop the cover off the fan and have a look for a fuse. Is a thermal fuse replaceable in the same way as a 'regular' fuse ? I have now found a simple schematic on a sticker in there , but unfortunately is has been rubbing on the hood and is unreadable. But it does give me a code and I can check it on line I had the notion to have a go at a fix on this because I did my washing machine about 2 years ago, saving myself some money. It was a relatively low cost fix and although it took all morning to grapple with it, it was a good feeling to bring it back to life (it was worn brushes, hence my thought in the original post that it could be the same - not knowing it was a different kind of motor to the fan) |
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Jem
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Post by Jem on Aug 16, 2020 10:43:42 GMT
Took the motor apart and no sign of anything like a fuse. But I did use my zoom on the iPhone to find this , which I dare say burnt through when I shorted it. I think I will throw the towel in at this point and accept defeat. The new integrated hood comes with the new carbon filter and lights etc , so perhaps it's time to 'upgrade'  IMG_4130 by |
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Post by wheelson on Aug 16, 2020 16:32:10 GMT
Sometimes replacement is best or at least less painful. It took me three tries on the clothes dryer to get it operational. The main reason for the repeated attempts there was that the dryer is in our basement, and our old house steps require an extreme effort to get large appliances down there. The kitchen oven was a bit easier to replace the broiler element, success the first try, but I'm sure you've noticed that most appliances have very sharp metal bits internally just waiting to rip human flesh. I guess that's "economy of design".
Best,
J. wheelson
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