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Cheap, SPAL look-alike Rad fans 80W type testing.


spitfire6

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Hi.
a picture of two fans. Blades are reversed.
Electrically they can rotate opposite.

I believe the top one will work better as a Pusher & the bottom as a puller.
Does anybody disagree with the above? I would like to hear why not.

The 80W does not mean 80Watts. @ 12VDC. Feeding the power from the alternator will get very close though.
 

SPAL are the best but my pair are pullers. 9" 80W type were the next day and cheap.
Cheers,
Iain. 
 

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I would expect the top fan to rotate anticlockwise and move air towards the viewer, and the bottom fan to rotate clockwise and move air away from the viewer.

Axial fan blades tend to be installed so the blades are backwards curved and I'll wager that's how these are designed and will work best.  I'd flip the blades to match whatever purpose you intend to use them for.

As to pushers or pullers?  There's a can of worms people argue about all day, but it's likely gains so marginal only an F1 team would notice!

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Hi,
I ran some tests and came up with the below:

           
Direction Electrical Connection Fan Blades Voltage Amperage Watts
pull Correct Reversed 00.70 0.30 00.2
pull Correct Reversed 12.00 3.59 42.9
pull Correct Reversed 13.50 4.25 57.3
pull Correct Reversed 14.25 4.57 65.0
Pusher Reversed Reversed 00.70 0.33 00.2
Pusher Reversed Reversed 12.00 4.38 52.4
Pusher Reversed Reversed 13.50 5.10 69.0
Pusher Reversed Reversed 14.25 5.49 78.3
Direction Electrical Connection Fan Blades Voltage Amperage Watts
Pull Correct Supplied 00.70 0.30 00.2
Pull Correct Supplied 12.00 4.13 49.0
Pull Correct Supplied 13.50 4.80 65.9
Pull Correct Supplied 14.25 5.20 74.3
Pusher Reversed Supplied 00.70 0.34 00.2
Pusher Reversed Supplied 12.00 3.50 42.0
Pusher Reversed Supplied 13.50 4.20 57.0
Pusher Reversed Supplied 14.25 4.57 65.0

To me, it's clear as said.
A supplier of these fans is adamant that these fans are designed to run in the opposite direction. They will run but not as efficiently if you follow their instructions.
Cheers,
Iain.

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Drawing more power just means more load on the motor, not necessarily more air being moved.  Which is what you're actually after.  That extra energy could be going towards heat and turbulence.

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Hi,
Added SPAL to the bottom:

Type Direction Electrical Connection Fan Blades Voltage Amperage Watts
80W Pull Correct As Sold 0.70 0.30 0.2
80W Pull Correct As Sold 12.00 4.13 49.0
80W Pull Correct As Sold 13.50 4.80 65.9
80W Pull Correct As Sold 14.25 5.20 74.3
80W Pusher Reversed As Sold 0.70 0.34 0.2
80W Pusher Reversed As Sold 12.00 3.50 42.0
80W Pusher Reversed As Sold 13.50 4.20 57.0
80W Pusher Reversed As Sold 14.25 4.57 65.0
             
Type Direction Electrical Connection Fan Blades Voltage Amperage Watts
80W pull Correct Reversed 0.70 0.30 0.2
80W pull Correct Reversed 12.00 3.59 42.9
80W pull Correct Reversed 13.50 4.25 57.3
80W pull Correct Reversed 14.25 4.57 65.0
80W Pusher Reversed Reversed 0.70 0.33 0.2
80W Pusher Reversed Reversed 12.00 4.38 52.4
80W Pusher Reversed Reversed 13.50 5.10 69.0
80W Pusher Reversed Reversed 14.25 5.49 78.3
             
Type Direction Electrical Connection Fan Blades Voltage Amperage Watts
SPAL No rotate Correct As Sold 0.70 0.70 0.5
SPAL Pull Correct As Sold 12.00 5.30 64.0
SPAL Pull Correct As Sold 13.50 6.10 83.0
SPAL Pull Correct As Sold 14.25 6.50 93.0
SPAL No rotate Reversed As Sold 0.70 0.70 0.5
SPAL Pusher Reversed As Sold 12.00 4.50 54.0
SPAL Pusher Reversed As Sold 13.50 5.20 72.0
SPAL Pusher Reversed As Sold 14.25 5.80 83.0

The SPAL is made Blow or Pull. Mine has code "A" so it's a Puller. an "A" is Italian for Pull.
Certainly, the current and energy drop when running in the wrong direction.
All the fans consume more energy when the convex edge is leading.
I was going to buy an airometer as I already have a manometer. I am saving my money.
The SPAL has been in use for a couple of years. It was stalled at 700mV and started to pull more current slowly.
Cheers,
Iain.

spal.thumb.JPG.3bac411211ae8f6755643f1ea3bbf414.JPG

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