[DeTomaso] Blower mystery demystified

[David D Fisher]

Ok,  after staring at it again last night and getting lots of good pointers from you gents, I think I have finally go to the bottom of all my confusion.  Here's what I found:
 
1) My motor was installed backwards when I got the car.   This is one of those cases where taking a picture before dis-assembly and then following the picture upon assembly will screw you up.
2) The arrows on my fans are "backwards" for the expected operation of pushing a high pressure air stream through the heater box.   Thus trying to follow the arrows is probably what had the first person put the motor in backwards.   In all fairness to centrifugal fan designers (and thanks to Tomas),  wikipedia shows that you can have a centrifugal fan with the vanes going straight or in either direction (forward or backwards) with different effects  (I learned something!)
http://en.wikipedia.org/wiki/Centrifugal_fan
3) There is also an error on SOBill's wiring diagrams (page 8 Pantera Place Wiring Diagrams).  The red blower wire is the low setting (current runs through the resistor) and the black wire is the high setting.  At least that is how it is on my car and also on the DeTomaso wiring diagram.  This led to some of my confusion about before and after airflow tests. 
 
 
So, all said and done, I am running with the blades pushing the air in the right direction (same as the animation on the top right of the wiki page) and in harmony with the shrouds, although opposite to what the arrows on the fans show.   Lots of air flow and quieter operation than what I had yesterday.
http://www.poca.com/index.php/gallery/?g2_itemId=36973
 
 
Ignore what I said yesterday about one side shroud being optimal and the other side wrong.   I was trying to visualize the blades spinning in my head and clearly screwed it up.
 
Thanks for all the pointers!
 
David
 
 
 

  

________________________________
 From: Mike Dailey <panteraplace at hotmail.com>
To: detomaso at realbig.com 
Sent: Monday, August 13, 2012 5:15 PM
Subject: [DeTomaso] Blower mystery
  
The fan cages on my 71 are metal but in general have the same shape of the
blades in your pic and face the same direction.  Looking from the driver
side of the car the fan turns counter clockwise as you would expect for the
blade to pull in air from the inlet and force it into the heater/evaporator
box.  With the fan on there is only suction at the fan inlet and pretty
decent air blowing out of the front side of the heater/evaporator.  If you
motor is tuning clockwise that would be reverse from what I have.  Is your
motor flipped with the blades on the wrong side because you want it to be
turning counter clockwise with the blade as in your picture?    



Mike

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