Hi,

I have a car that used to have a mechanical fan but for milage and other reasons I put in an electric fan from a performance fan mfg.

Well... about 1000 miles after I installed it, it stopped working. I pulled it out and connected it directly to the battery to test and it just arc'd and sparked. Obviously broken.

I replaced with another of the same model and in no less then 100mi it did the exact same thing.

So, I sent both back to the mfg and they called and said the reason they broke was from 'excessive amperage'. Which I cant understand since the fan is only going to PULL want it wants from the battery no ?

I cant drive the car w/ no fan and i'm hessitant to put another fan in since I think I know what will happen. Also, I have never heard anything about this problem before. Niether has the mfg. So I'm guessing its wiring or the way I have it hooked up. Which looks like the pic below.

Also, the mfg says the fan draws ~11amp when on (but a little more right at turn on instance) but the company I got the fans from includes a 30amp fuse (which I used).

I'm confused. Both fans when bad w/o blowing the fuse. What the hell could be going on? Anyone have an ideas ?

Thanks In Advance

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I'm not an automotive expert but I've heard that transients on the +12 line can be fairly bad. Its possible that a spike damaged the fan coils causing the burnout. Fuses work fairly slowly so its possible that a short transient didn't put enough power into the fuse to damage it.

Is the fan rated to work at automotive temps?

 

Maybe this is a long shot...

Is the fan controlled by it's own thermostat so that it only comes on when needed, or did it run all the time? If it ran all the time, maybe it wasn't up to continuos duty? I see the CPU symbol, was this what was turning the fan on and off?
-or-
Maybe it was being force to turn in the opposite direction it wanted to go when the car is in motion, overloading the motor?

 

this is the most stupid basic question, but you did connect it the right way, right?

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The fan spins the right way. Its hooked up right. I'm wondering if maybe the ground has a poor connection... But I also think that would blow the fuse.

The fan is controlled by a pic. It reads in the coolant temp sensor and triggers a NPN transistor to connect the relay coil to ground. This is a proven working system. And since its on the control side of the relay, and the relay is only triggering when its supposed to.

I was curious so I talked to the mfg and they confirmed that spinning it the wrong way will not hurt the fan. Its just a motor.

This is a performance automotive fan. Rated to 300+ degress. They're expensive and I'm worried about adding another if it will just suffer the same fate.

 

I think zevon8 is on the right track ..Does the fan have a directional arrow showing which way the air will flow? If installed backwards, the fan will be forced to run backwards by the air flowing while the car is moving and when the thermostat kicks in it will have to fight the air current to run ,causing the fan motor to overheat..All this assuming the fan blades aren't binding or rubbing on anything..

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gerty

 

The fan spins the right way.

This is a puller setup. Ie: The fan pulls air through the radiator.

I could have gone with a pusher, but they dont work as well and are better suited for hotrods.

Also not binding, stopping or interfering with anthing. The likelyhood of two bad fans from this company is VERY poor.

I'm stummped.

 

Your diagram shows no protection for the fan at all. Now, if the fan is known to be rated for such nasty electrical environments, then it may be ok but if you are not sure, you really need some protection. Over stressing can drastically reduce its life. Also, it may have actually failed for an undiscovered reason and the excessive amperage is a result of the original failure. So because it experienced excessive amps doesnt mean that is the root cause failure.

Have you verified that it has adequate room for proper airflow through the fan? When the airflow is impeded, the fan becomes excessively loaded.

 

Its an engine not a computer chasis... There is ~ a foot of room behind the fan.

EDIT: What do you mean protection ? It has a FUSE... What kind of protection are you looking for? Some sort of Overvoltage-proof-submerible-analog-to-digital-driven-microprocessor-running-at-3Ghz-and-a-ups-constantly-monitoring-ameter-with-built-in-temperature-alitiude-ultra-protecto-circuit ? Go look at your car, chances are it has an electric fan with a relay and a fuse. Thats it.

The conditions of the fan are not out of the ordinary and I'm certain the fan can handle being run for a long period of time with no damage (they are warranteed for 3 years)

What I'm wondering is if the fan siezed up why didn't it blow a fuse... Why after two dead fans has the fuse not poped (I checked the fuse with another and that didn't blow either.

I'm not sure what will happen with a lower rated fuse... If it doesn't pop just as this current one isn't popping then I have no idea where the problem could be.... Connecting the battery terminals with a 30amp fuse in between (ie: a shorted fan) should pop a 50amp fuse with no problem... If I put a lower amp fuse in and it DOES pop... well, then I guess I must have a crappy connection somewhere (no ?)

Ideas ?

 

perhaps something peeling off something inside there and it got jammed into the fan motor or something like that. or your radiator is leaking and little by little its doing something to the fan. im not sure what effect water and coolant has on an electric fan. its the best i got :roll:

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Have you done some basic electrical tests on your car? eg, measuring the system voltage (if the regulator is blown, voltage will be too high). Or when you connected the fan to the battery, did you measure how much current it was drawing?

No, that wouldn't normally blow a fuse - a poor connection would cause a lower current draw.

 

Can u see the motor?

pull the original one apart and have a look to see if there is any damage inside...

 

Exactly!, I suspect they are conning you - assuming you have quoted them correctly?. No one with even the slightest electrical knowledge would use the phrase 'excessive amperage', the correct term would be 'excessive current'.

I suggest you get back in touch with the manufacturer and ask for 'proper' details, not a load of made up rubbish!. If they claim it's caused by 'excessive current' then ask them why, electrical conditions on the car won't cause it, although excessive mechanical load on the motor would cause it to take excessive current - causing the motor to overheat and burn out.

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next time put a smaller fuse in line with the fan... and be prepared to replace it often.

a car battery's voltage can spike pretty badly, sending a high voltage across the fan and in turn sending way to many amps through.

this is exspecially true for older cars that lack modern electrical systems.

if it burns out after that... then i'd say you're stressing the fan to much as suggested.

maybe try a different brand of fan?

 

Is it possible that the controller is starting and stopping the fan a LOT - causing it to draw the start-up current, stop again, draw the start-up current, with no rest (cool-down) time ?

I don't like the "too much current" idea - too much current must have been caused by :-
- too much voltage (Phasor's idea)
- too frequent starting causing overheating of the motor coils
- faulty manufacture (as you said - unlikely - but not totally impossibe, are they from the same batch?)
- stalling (fairly obvious - dead dog wedged through radiator ?!)

Could the fan be happier without the PIC controller (just wired to ignition switch - a bit crappy but it could (dis)prove an idea)?

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