Two speed/ single speed domestic extractor fan ?

At the moment it's running at a single high speed and is quite noisy. How do they work? I note that there are three leads coming from the fan motor, two of which are connected i.e red & blue. The third is white and isn't connected to anything, I assume it's a tapping on to the field coils to reduce the magnetic field, and cause slippage to slow it down. would this cause the motor to run at a higher temperature? or am I barking up the wrong tree here. I'm loathe to try connecting the white lead without some guidance.

Don

Reply to
Donwill
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You're really not giving enough info here. If you want to quieten it down, a series dropper is effective. There are also several other ways:

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Reply to
meow2222

motor, since it's got 3 leads going to it, a red, blue and a white, and as I said before the white lead is terminated with an insulated crimp connector which is not connected to anything. I suspect the manufacturers (Silavent SVC6) use an universal 2 speed motor which can be used in one speed or 2 speed mode. I'm guessing that if I connect the white and blue across the mains and disconnect the red it will run at a lower speed but I 'm loath to try it.

On the back of the installation leaflet it has the following info :-

230V- AC. 50Hz High speed /Single speed 35W Low Speed 25W

Don

Reply to
Donwill

why not check it with a multimeter, and if it fits what you suspect, try running it in series with a lightbulb. At your own risk.

NT

Reply to
meow2222

Good idea, I'll try that when I'm a bit more awake. Cheers Don

Reply to
Donwill

Ok I've measured the resistance of the windings and they are as follows :-

Starting at the top draw two resistances in series vertically one above the other. Now you have 3 wires connected to the network, a red one at the top, a blue one as a centre tap, and the white one at the bottom.

DC Resistance, red to blue = 278ohms. , blue to white = 80 ohms , red to white = 358 ohms The red and blue wires disappear into a printed circuit, the white is floating and insulated. My thought is to connect a changeover single pole switch (break before make ?) as follows :- common connect to pc where the blue went. c/o1 blue, c/o2 white.

Any comments appreciated.

Don

Reply to
Donwill

Looks like it all fits what you suspect. Switch sounds right, but test the fan first of course.

NT

Reply to
meow2222

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