Instead of those Expensive Fans, Why don't you go toi the Auto Wreckers and pick up some old fans. Up Here I can buy GOOD Used Fans for about $10.00. Other than looks, I doubt those Performance fans are much better.

Before going any Farther, Check the Battery Voltage, With the car Running at a reasonable RPM. It should Not Exceed 14.5 Volts. If it does you have a regulator problem and a definate cause for failure of the fan.

Also, Instead of using a Relay, why not use a Mosfet to Sink the negative lead of the fan to ground. Less Chance of Relay Chatter, or Contact Resistance Problems which may Cause Excessive Current.

As to Amperage or Current, Both are Totally correct and I can easly understand a Manufacturer using Either Term.

I do Agree that Excessive Current Usually Requires Higher Voltage. But Also by Too Much Drag on the motor, caused by the Fan, or possibly a Problem with the Relay as above.

Hope this Helps.......Gary

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Is it drawing enough air through the radiator?

It may need a lot of air to cool itself off and your radiator may have insufficient airflow through it. Is there room around the sides of the fan for extra air to be drawn in or is it pretty well sealed to the radiator?

It may pull enough air to keep the car cool enough, just not itself.

Sounds to me like the fans are faulty though.

 

Are you sure you've connected the fan the right way round? This can be a common problem when using fans

 

Is it a North American term then?, it's certainly not a European one, and not something I've ever seen in any American texts.

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I Believe Its is an Older Term for Older guys like me. *SMILE*
Well at least I have heard it used a lot, here in Canada.

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LOL.... :shock: But you still dont know why your fan dies..

"a shorted fan should pop a 50amp fuse" well, yes if it failed with a nice solid short.. I think it is an important clue, that the mfg said "over amperage" yet your fuse didnt pop. Well, not everything in the world fails short or open. It could, I suppose have failed with a couple ohms short.. enough to fry it but not enough to pop a presumably SLOW blow fuse.

..and added protection is assuming you may have something else wrong in the system that you have not ruled out... There is always the chance of more than ONE problem going on.. if your issue was a simple no-brainer, you'de have solved it by now eh?

Isnt it amazing how sometimes the simplest of things turn in to real head scratchers..

 

I'm not going to split hairs about what term they used. This is company I deal with now and then and do not think they're 'conning' me.

If the fan were to stop... say because it was being jammed up by somthing (really really unlikely) would that also not blow a fuse ? Also: WHY AM I NOT BLOWING FUSES WITH A DEAD FAN !? (frustrating :evil: )

Part of the deal was that I can not open the motor w/o kissing my fan replacment goodbye. I have no idea what it looked like inside but was on the phone w/ the tech when he cracked it open. He said it was completely trashed. That the solder on the brushes had completely melted away.

This is a very modern car and I have measured no spikes higher then 40V when starting. This is not some old unreliable pos. If I were pulling too much current why isn't my fuse popping? I mean, how can the fan be getting to much but the fuse is within operating range. Its not like the fuse is a regulator, it doesn't care if there is 0 and 29amps on the line. I really really doubt the fan is getting stuck or blocked up, so what could cause it to "pull" too much current w/o any damage to the fuse or relay ?

The controller has a 2 second timed delay per operation. Where it can not turn the fan on or off more then once every 2 seconds. Even then I have a deadband in there to make sure the fan doesnt just keep turning on or off every cycle. At idle the fan will turn on, the radiator will cool then engine down and about a minute later the fan will shut off, then when it gets hot again, fan on. (This is how YOUR car works too.)

Normal voltage at idle is ~12V. Like I said this is a very new system and not really prone to the same quirks as an older car.

I'm using a relay since I already have one for the fan. NPNs are cheap. And I have found mosfets a little too 'sensitive" for my tastes. (I had this system on a mosfet that would trigger whenever it wanted to unless I touched the fet with my finger... the problem was it was not biased to ground... like I said, too sensitive. I just couldn't see that thing lasting forever). This fan has a reputation for being the best in the wold and I have not found another that could possibly fit this application. Besides I think the problem is with somthing else in the car.

I really appreciate all tje help! This is frustrating for me and I've tried everything short of ripping it all out and starting over (VERY VERY tough to do since all the wires are sealed up in the factory convelute)

The tech suggested that although he doesn't know the system that maybe I have a poor connection somewhere and its just enough stress on the fan to burn it up but not enough to blow my 30amp fuse ?

Does that stick ?

 

Optikon: Your on the right track,

This is a slower then normal fuse I belive.

Do you think its possible that the fan even in its dead state is sucking up just enough current not to blow that fuse ?

What I dont understand is that when the fan is dead, if you connect it to the battery, this thing lights up like a sparkler... So why doesnt it blow the fuse once its already dead ?

Maybe I have a bad solder connector that is just roughly a few ohms poor of perfect that is heating up the fan ? (But that gets me back to the fuse again :?: )

 

Don't let a bad experience with a mosfet put a sour taste in your mouth. A properly designed mosfet switch circuit will far far far far outlive your fan, relays and you very likely. Relays being mechanical in nature, are the most unreliable elctronics you have in there, second only to the fan itself.

Since the fusing seems to be in question (it is isnt it? 30 vs 50, why no blow etc..) I think this should be straightened out first. Can the tech tell you precisely what the fan needs to draw? It wouldnt be the first time failures like this happened because the fuses were not properly sized but worked in "most" systems..

 

He mentioned nominal pull is ~12amps.

The company I went through to get the fan brought in sends out a stupid relay harness that they make that has a 30amp fuse in it... So upon seeing that thing I said "Well, THEY supply a 30amp fuse, thats what I'LL use"... (dumb)

I made the whole system so that when I sell the car, any none electronics guy can just replace the relay if it brakes. (I doubt my NPN/PCB setup in about 3oz of potting compound will fail before then rest of the car)

 

One thing that there is alot of misunderstanding about in regard to fuses, they are really meant to protect the wiring, not the device. The other thing is that they do not respond instantly to the rated current.

For example, a 30 Amp fuse will not open circuit instantly at 30 Amps, infact, it is designed to carry 30 Amps. From the Littlefuse catalog, ( one of the worlds largest fuse producers ) a 30 Amp, ATO style automotive fuse has a MINIMUM opening time of 100 hours with 110% of rated current flowing through it. This means it will take a minimum of 100 hours to open circuit with 33 Amps flowing through it. For the same 30 Amp fuse to open circuit in less than 1 second ( maximum 600 seconds ), it requires 40 Amps.

You will definitely have done damage in this amount of time if the fan has a nominal operating current of about 12 Amps.

Taking into account the fans inrush current, even at say 20 Amps, for a duration of maybe 0.5 seconds, you need something more in the order of a 15 Amp fuse.

I think that this fan suffered from insufficient cooling, and baked itself. Fan motors are notorious for having extreme temperature rise, since they generally in their own airstream, and can/should be self cooling. It is not uncommon to see a rating of 60*C over ambient on a fan motor. Try touching something that is 60*C. And then remember that this is 60*C over ambient, so add the temperature of the radiator air to that figure.
At these temps, its really easy to melt solder, burn windings, dry-up and seize bearings, etc.

I think the manufacturer is giving you the run-around. If it was installed as marketed, used under normal operating conditions, and failed that quickly, something is wrong with it. Bottom line.

 

Does the motor have built in suppresors, if not the you should fit
a automotive supressor as near to the + of the motor to stop the brushes
arcing and overheating(sure way to kill a motor).
When you connected your "dead" motor across the battery, you say it lit up,
this was due to the brushes arcing on the commutator which possibly would not blow your 30 amp fuse , but a short circuit armature would deffinitly blow the fuse(or send out smoke signals).


Martin

 

i dunno if someone already mentioned this, but if the fan needs time to shut off and cool down once in a while, maybe the fan is somehow being always on and therefore ruining it.

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Do you still have this 30A fuse? maybe a "smoke" test is needed, go and short that guy out and see if it'll pop.

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A bad connection/few extra ohms will actually reduce current, not increase it.

well, maybe that was the problem then, there shouldn't be any solder on the brushes! :lol: