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Discussion Starter · #1 ·
Sorry if there have been posts about this before, but cannot find any recently. The cabin Sensor Fan on my 94 CSE is very noisy. Have given it a healthy squirt of compressed air, thinking that would blow the muck out, but fan still noisy. Any suggestions ? The fan on my 1990 16v is so quiet I didn't realise that it stayed on for 2 minutes after switch off until I got the CSE.
 

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Discussion Starter · #3 ·
Thanks Mutungi - didn't know if the WD would attact more dust to stick to it, but will give it a burst tonight - won't be taking unit out though, it has to go out thru' the back doesn't it, having removed the ACC panel first ?
 

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Yes, just pull out the ACC panel and access the fan unit from behind...I used WD-40 because it was the only lubricant spray I had....there may be more refined electrical lubricant sprays around which would perform equally if not better. Also, it is very easy to pull out the ACC panel with the traditional 'feeler gauges' made with various thickness steel fingers! Do not try screw drivers, etc as they will damage the walnut!
 

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Revisiting an old post as similar problem...

The fan on my sensor is reluctant to start rotating - I tried stripping down & lubricating, but on ignition the fan dithers as if trying to start, but doesn't quite manage it. If I give it a slight spin to start, it runs fine.

It seems as if the fan rotor is magnetised & can't break free of the driver 'poles' underneath. (It is not a motor with commutator, but seems to use an alternating magnetic field to provide the rotation. I can't work out how it starts, though)

Any sparkies out there with experience?
 

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The sensor does indeed pull out of the back of the dash, and it's quite easy. However, if you don't want to do that, remember that the grille over the front of the sensor pulls out into the car, and should give you better access from the front.
 

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I have the sensor completely exposed - what seems to be happening is that when ignition on, the fan (in effect the motor rotor)'shakes' as if trying to break the magnetic field. Looking at the movement, there would not seen to be any mechanical friction to restrict movement. If I give it a flick, it will spin freely. Sometimes it manages to start by itself.

Is it possible the rotor need demagnetising?
 

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A non-commutator fan that has a DC supply is known as a brushless DC motor.
The motor converts the DC into AC (Using a circuit built into the motor) which alternates the voltages to the outside?
The permanent magnets are part of the commutator, not the casing.


I found this which will hopefully explain it better!
But basically, there is probably a fault in the integral circuit, which means you may have to replace the motor complete unless you can find someone who can replace the components in the circuit!

Hope it helps

Skiddins

http://www.bodine-electric.com/pdf/bldc.pdf
 

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I think you'll find that brushless DC motors don't use a commutator at all.
The circuit that creates the alternating electromagnetic fields powers the 'outer' electromagnets (attached around the inside of the motor 'can')

The armature just consists of magnets which are pulled etc by the outer elctromagnets.

I'm afraid i haven't covered the different types of windings, because i haven't a clue! Skiddins
 
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