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Heater blower fan polarity


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I’m rebuilding a heater box, mining parts from several boxes. The only good fan I have is a Bosch-made in Spain so it spins the wrong way. The rotor is in great condition and so are the brushes. It looks new, possibly could be, just a few decades of dust in/on it. I could just flip the wire connections BUT that means the rotor rotates into the brushes rather that the brushes dragging on the rotor. Is there a way to change the brush/ terminal mounting to change the rotation of the rotor? The previous owner mounted a fan with a set screw and ground a concave dish on the shaft for the screw.

Thanks,

Dan

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Figures that the SpaniardFan is backwards...

 

You have to re- clock the brushplate- easy on big motors that are designed for it,

super hard on little ones like this.

 

Honestly, I'd find another fan blade.  3d printing jokes aside, this is something that could 

be printed (with support) in ABS.

Or scrounged out of various inexpensive air handlers.

 

t

no, before you ask, don't use a transmission to reverse it, either!

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Flipping the fan doesn't change the blade angle.

 

Duh... I recall the HO car racing set I still have. To make the cars go the other way, I flipped the permanent magnets. BTW the Jaguar XKE was the fastest one of the bunch. Not sure if the fan motor permanent magnet can be removed and flipped.

Dan

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I figured it out. There’s no need to take off the red plastic terminal holder. Disconnect the brush units and springs from the metal housing /frame. Reconnect on the same side but flip them over so they are now dragging on the rotor. A dentist pick works great for un-hooking and re-hooking the springs. Carefully re-bend the wire leads from the push terminals to the brush holders 
You will need to reverse the wire connections so what was positive is now negative, etc. Caution, the uninsulated negative lead is now positive. You don’t want that grounding on the frame. I might un-solder it and sleeve it or shrink wrap it.

Dan

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I had forgotten that the brush carrier was reversible.

(it might not be on all motors)

That does make it pretty straightforward.

 

It's brush 'clocking'- apparently there's a science to it

when you get into the kiloamps.

Like, plasma science.

 

Thanks for the update!

t

 

 

 

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Just to clarify, the red plastic terminal piece stays in the original place. The black brush carrier is un-clipped and put on the opposing metal frame; spring too. Enjoy the breeze!

always enjoy your posts Toby!

Dan

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