I don’t think there are any response “off the wall” they have to do with how an electric fan operates “properly”. There is no need of an electric fan or any fan when driving above 30 – 35mph, regardless if it is for the engine temp or A/C. There is plenty of air flow at those speeds to not need any fan.

As people have stated no one is ever able to drive at speed and have to sit in traffic and thus the need of a fan, be it electric, clutch or flex. Anyway if someone is constantly running an electric fan when driving above 35mph they will eventually cause damage to the fan since it is not designed to be used then.

If someone, or this person had a switch inside the cab and was running the fan all the time when driving at freeway speeds they would cause the fan motor to burn up at some point unless it had some type of internal protection like a thermocouple.

As I stated before as far as clutch fans go they do not engage when the A/C is switched on. So the topics brought up are good as far as relating what may have happen to this electric fan. It could have been operated incorrectly or could have been wired wrong or was just plain defective to begin with.

 

I love my JDM e-fan. Had it on my truck for two years now nad it works great. I have installed other venders e-fan kits and the JDM is hands down the best kit. I have towed 4000lbs over 700 miles in a day cruising at 85mph and got 15mpg and never had a cooling problem. I like the e-fan cause it's alot less noisy than the stock fan and when it comes on I think the longest it has run is 30 seconds. One of there best products.

 

Ok, so tell me how the fan KNOWS the truck's at 30mph. It's simple you turn on the a/c, it also turns on a relay to power the e-fan all the time. Also the ram effect of the air at that speed and above will make it easier for the fan to turn NOT increase the load.

 

To be honest I am not sure just how the electric fan operates in cars that are designed with them. Perhaps the computer monitors when someone switches on the A/C and if the computer sees that the speed is above a certain threshold it will not allow a relay to activate. Just not sure how the circuit works without having a schematic in front of me.

As far as the fan turning easier with the “ram air” effect is not correct. The fan is designed to spin at a certain RPM. Let’s say that is 3600rpm. If you force the fan to turn at a slower or faster RPM it will cause heat in the motor windings and the motor core. The windings of the fan motor, as you know, produce a rotating magnetic field. The rotor chases the magnetic field and causing the fan to spin. With the rotating magnetic field and the rotor chasing it sets up a BEMF (back electro magnetic force) this opposes the actual rotating magnetic field and causes heat.

Motors are designed taken this BEMF into account. However, slowing the rotation of the fan, or increasing the rotation of the fan will increase the BEMF and that will increase the heat build up of which the motor is not originally designed for. This additional heat build up degrades the winding insulation causing it to prematurely break down. When broke down enough it causes internal winding shorts and opens the winding circuit.

So, operating an electric fan at say freeway speeds will cause it to spin faster. As you stated because of “ram air” effect. This will cause the BEMF to increase and will prematurely break down the winding insulation. This may not happen for months or years.

The only reason to have a switch inside the cab is to have a back up so that if the heat sensing circuit malfunctions where the electric fan will not work at idle or slow traffic you have a means to bypass it and turn it on. The other reason is for people going to the track and wanting to cool their motors down between runs. There is never a reason to turn an electric fan on at highway speeds. It provides absolutely no cooling effect at all…

 

First of all without trying to offend you, I do not need any of my motor theory explained to me being that I am an electrician and have been one for the past 12 years. As I explained to you in my last post when you turn on the a/c it turns on a relay to power the main or a secondary fan to run all the time the a/c is on period. You need the air flow through the condenser to cool. No computer control for this what so ever.

Secondly a motor overheats due to an increase in current. Driving a motor faster with an external source will not subject it to a current increase. So it will not heat up. We're not talking a servo motor here, just a simple induction motor with no position or speed control. This is getting away from the original post. Believe what I said or not, I'm done.

 

Yeah, only stated facts buddy . Id be pissed as hell if ive been waiting since the begining of sept. for a replacement .

"they spoke to JDM after it happend and they told him that one of the switchs or some thing was bad and they will send him a new one. that was Sept.3 /03 and we are still waiting"


We hear this kind of stuff alot for some reason? If it smells like shiat it must be shiat right?I feel bad for him having to deal with it .Been there done that.

 

Hmmfff...Never mind. I was going to bash YOU retics....But trying to argue with an ignorant man is a frustrating experiance!

 

[
QUOTE]Originally posted by whip
Hmmfff...Never mind. I was going to bash YOU retics....But trying to argue with an ignorant man is a frustrating experiance! [/QUOTE]

bash away brother just take your cheerleader skirt off so it dont get dirty .Plain and simple if hey said they were sending it they should .

 

No offense taken. However you are partial correct about why a motor overheats. Yes an increase in current draw heats up a motor, as does an increase of BEMF. It causes more eddy currents in the stator core and causes more current in the motor windings due to the opposing magnetic force (also known as generator action). An induction motor does, in a way, have speed control. It will spin as fast as the rotating magnetic field allows it to, with some slippage of course, around 2%. When you interrupt this speed by slowing down or speeding up the fan externally you will cause damage to the motor windings.

I have worked with motors for just about 20 years now. I did not mean to offend you about motor theory just explaining for others that may be reading wondering what we were talking about.

 

I have 50,000 miles on the JDM electric fan, and it is working awesome

Best mod I ever did

 

LOL!!!!! aint that the truth!

 

Human nature being what it is.....it appears these basher threads are good for business. LOL......Jim has probably sold 200 fans in the last 3 days
Dale

 

 

i want one!

 

Later...
Bruce