What the Hell happened here???
07-15-2009, 02:09 PM
#1
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What the Hell happened here???
Changed the upper radiator hose on my car, started the engine and was making sure the air was out of the system and I see wisps of smoke coming from the fan fuse holder.
I see this:
How in the world can a fuse melt without burning the element???
I have never witnessed this before. It's the 30amp fuse that came with the controller. Woweeeeee, that would have been fun to put out in a hurry.
I see this:
How in the world can a fuse melt without burning the element???
I have never witnessed this before. It's the 30amp fuse that came with the controller. Woweeeeee, that would have been fun to put out in a hurry.
07-15-2009, 02:52 PM
#2
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with what controller? the electric fan thermostat? was the fan operating at the time?
there a 2 things I can think of
1) made in china fuse and for some reason 30 to 40 amps were being continuously drawn through the fuse and finally heated the plastic enough to melt it without burning the fuse element
2) one side of the fuse was used a shunt allowing current to flow through only 1 leg of the fuse (does not seem possible in your situation)
-Gun
there a 2 things I can think of
1) made in china fuse and for some reason 30 to 40 amps were being continuously drawn through the fuse and finally heated the plastic enough to melt it without burning the fuse element
2) one side of the fuse was used a shunt allowing current to flow through only 1 leg of the fuse (does not seem possible in your situation)
-Gun
07-15-2009, 03:19 PM
#5
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What fan are you using and do you know how many amps it says it should draw?
Turn the fan by hand does it spin very easy or do you feel some resistance?
I'm not sure how an open ground could be an issue as there would be no electron flow.
Im guessing your fan should pull about 15 amps at 13V it looks like its pulling close to 30 it could be failing bearings on the electric motor.
-Gun
Turn the fan by hand does it spin very easy or do you feel some resistance?
I'm not sure how an open ground could be an issue as there would be no electron flow.
Im guessing your fan should pull about 15 amps at 13V it looks like its pulling close to 30 it could be failing bearings on the electric motor.
-Gun
07-15-2009, 04:54 PM
#7
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It's a Derale fan rated at 23.40 amps. The Derale thermostat is rated for a max of 25amps, but the relay is rated for 30/40amps and the supplied fuse was 30amps. I just took it all apart and the motor doesn't seem bound up. It has a magnetic resistance, but spins easily. I shot some lube in the bearing.
Runs fine, still sounds like a blow dryer, but always has. I guess I will just keep an eye on it. A fuse should blow before it melts I would think.
Runs fine, still sounds like a blow dryer, but always has. I guess I will just keep an eye on it. A fuse should blow before it melts I would think.
07-15-2009, 05:12 PM
#8
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Water is a conductor, you get water on a fuse and it provides another path for electricity to travel, enough electricity and it makes heat. Not all of it goes through the fuse circuit so the fuse doesnt blow but it overheats.
If you dripped water into it while changing the upper hose it could do that.
If you dripped water into it while changing the upper hose it could do that.
07-15-2009, 06:06 PM
#9
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I dont think any of us have an amp gauge that will read above 10 amps (unless you have a nice induction clamp amp gauge)
I guess a wacky way to find close amp draw would be to buy a 10,15,25,30 amp fuse and get a leaf blower (told ya it was wacky) get the car warm so the fan would come on (lower the fan thermostat so it stays on as long as possible) (note the direction of turn) and then pull out the 30 amp fuse (the fan should shut down) use the leaf blower to spin up the fan at about same speed and direction and replace fuse with 10 amp while at the same time removing the leaf blower so the fan now spins on its own.
if the fuse blows right away you know amp draw is above 10 amp...the leaf blower prevents current spikes that occur as the fan spins up from a dead stop (like when the lights in your house dim when the a/c comes on)
the above is probably a waste of time unless you're really concerned about it possibly drawing too much current...
Im betting it was a crappy fuse replace with recommended 30 amp and let the fan come on and place your finger on the fuse it should be maybe warm to noticeably warm... I doubt it would get hot enough to burn you.
Let us know
-Gun
I guess a wacky way to find close amp draw would be to buy a 10,15,25,30 amp fuse and get a leaf blower (told ya it was wacky) get the car warm so the fan would come on (lower the fan thermostat so it stays on as long as possible) (note the direction of turn) and then pull out the 30 amp fuse (the fan should shut down) use the leaf blower to spin up the fan at about same speed and direction and replace fuse with 10 amp while at the same time removing the leaf blower so the fan now spins on its own.
if the fuse blows right away you know amp draw is above 10 amp...the leaf blower prevents current spikes that occur as the fan spins up from a dead stop (like when the lights in your house dim when the a/c comes on)
the above is probably a waste of time unless you're really concerned about it possibly drawing too much current...
Im betting it was a crappy fuse replace with recommended 30 amp and let the fan come on and place your finger on the fuse it should be maybe warm to noticeably warm... I doubt it would get hot enough to burn you.
Let us know
-Gun
07-15-2009, 09:43 PM
#10
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Join Date: Mar 2009
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I dont think any of us have an amp gauge that will read above 10 amps (unless you have a nice induction clamp amp gauge)
I guess a wacky way to find close amp draw would be to buy a 10,15,25,30 amp fuse and get a leaf blower (told ya it was wacky) get the car warm so the fan would come on (lower the fan thermostat so it stays on as long as possible) (note the direction of turn) and then pull out the 30 amp fuse (the fan should shut down) use the leaf blower to spin up the fan at about same speed and direction and replace fuse with 10 amp while at the same time removing the leaf blower so the fan now spins on its own.
if the fuse blows right away you know amp draw is above 10 amp...the leaf blower prevents current spikes that occur as the fan spins up from a dead stop (like when the lights in your house dim when the a/c comes on)
the above is probably a waste of time unless you're really concerned about it possibly drawing too much current...
Im betting it was a crappy fuse replace with recommended 30 amp and let the fan come on and place your finger on the fuse it should be maybe warm to noticeably warm... I doubt it would get hot enough to burn you.
Let us know
-Gun
I guess a wacky way to find close amp draw would be to buy a 10,15,25,30 amp fuse and get a leaf blower (told ya it was wacky) get the car warm so the fan would come on (lower the fan thermostat so it stays on as long as possible) (note the direction of turn) and then pull out the 30 amp fuse (the fan should shut down) use the leaf blower to spin up the fan at about same speed and direction and replace fuse with 10 amp while at the same time removing the leaf blower so the fan now spins on its own.
if the fuse blows right away you know amp draw is above 10 amp...the leaf blower prevents current spikes that occur as the fan spins up from a dead stop (like when the lights in your house dim when the a/c comes on)
the above is probably a waste of time unless you're really concerned about it possibly drawing too much current...
Im betting it was a crappy fuse replace with recommended 30 amp and let the fan come on and place your finger on the fuse it should be maybe warm to noticeably warm... I doubt it would get hot enough to burn you.
Let us know
-Gun
I have a clamp on ammeter somewhere, but I don't think it works. My neighbor does some electrical work and I think he has a working one. I went to get gas and the fan ran fine and the fuse seemed okay. I will double check it tomorrow.
Thanks for the suggestions.