10 replies to this topic

[Deathrow]

Here's one for any of you who have rebuilt a heater in the past. I took mine completely apart and didn't take enough pictures.

 

So I have a few questions, all related to the same topic, rotation:

1. Which colour fan goes on which side?
2. Which direction does the motor rotate?
3. Which way round do the green and black wires go where they attach to the motor?

Admittedly, with an answer to question two I can work out the answer to question three.

 

Thanks in advance.

[J808]

On mine which I refurbed the motor a few months ago, the black fan was on the side of spade terminals. The black cable was on the terminal closest to the top of the fan casing when installed.

[Ethel]

Radial fans will spin so the blades travel from the narrow end of the housing towards the fatter end. The thick end of the blades will be the leading edge - pretty sure that'll be the outer side of the fan. 

[KTS]

from this view, the motor would spin the fan clockwise i believe

 

[DeadSquare]

Why would you spin it clockwise ?

 

It is not trying to scoop up air and collect in in the centre of the fan.

[KTS]

Why would you spin it clockwise ?

 

It is not trying to scoop up air and collect in in the centre of the fan.

 

are we to divine from that comment that it definitively spins counter-clockwise ?

[Chris1275gt]

Can’t you just touch the wires to a battery.

[DeadSquare]

 

Why would you spin it clockwise ?

 

It is not trying to scoop up air and collect in in the centre of the fan.

 

are we to divine from that comment that it definitively spins counter-clockwise ?

 

Well, it is logical to me.

 

The inside of the blade catches the air, and if the air inside the fan is spinning centrifugal force is going to throw it out through the blades, which is why the outer part of the blade is angled to let the air slip away.

[Ethel]

It works mostly on centrifugal force (twizzle something on a string, e.g. Swingball,  and the string points in the direction of centrifugal force because it provides the reaction force to stop it flying off). Think of the gaps between the blades as ducts or jets. They curve to eject the air in the direction you want it to go - around the scroll of the housing.

 

You can have the inside edge "slicing" in to the air, more like a  wing. It's actually more efficient, but also noisier and harder to make in to cheap plaggy mouldings because the blades need to be longer.

[KTS]

For reference; having checked my heater unit which blows in the usual asthmatic manner (..so i guess does suck in some sense..), and the fan does rotate as I thought

[Deathrow]

Thanks for your responses everyone. I didn't realise this would open such a debate which in itself is quite interesting.

 

What I have discovered is that I can't actually wire my motor the wrong way (at least not without a great deal of effort) because one wire has a male spade and the other a female. I will let you know which way the motor actually spins when I've got it back together.

I did also notice that both the fan blades have a direction arrow on them which would indicate that they turn with the outermost part of the blade leading. So referencing the picture KTS shows, that white fan will turn clockwise.

 

Had a quick search around and found some interesting information here on Wikipedia about the applications of the various blade orientations. Seems like the arrow on the fans indicating rotation is correct.

 

Again, thanks everyone for the comments.