Electric Fan is it a better fan???

One caveat with the sensor that you zip (or put through the fins) on the radiator. I've used them a bunch, and twice I've been bitten by this: If you mount it up high near the upper hose, (which is good - temperature changes quicker there) you can run into trouble if the water drops below that level for whatever reason. It won't come on. So what I do is actually put the sensor inside the upper hose. That way it will still work as long as there's coolant moving. Or there's the other type like Scooper has that just screws into the manifold like a temp sensor.

 

..and how would you wire this light?

...Frank...

 

Parallel with the fan.

 

I've been thinking of going this route too, this is a good thread. FOr my 2 cents I don't see how an alternator can have increased drag by having more electiral use, it is not like a thermostat that it clicks on and of as electric needs increase,

When an alternator is overloaded it simply means it is not producing enough to keep up wiht demand.

I'll be the first to say I am not an electronics expert but a generator is nothing more than a motor operating in the opposite manner as an electric motor,

The drag is the magnet, with the coils spinning within it, now if you upgrade from a regular duty alt to a heavy duty their may be more drag , but if you are already using a heavy duty alternator I don't see how there is a trade off, I'm going electric, when I get to that point

 

Well, I can say that it is a fact that the more load you put on the alt, the more drag it puts on the engine. This can be demonstrated easily on my brother's '92 Nissan Sentra. It has a little 1.6L 4 banger, with two big electric fans to keep it cool. When the car is sitting at idle, and the fans kick on, the idle drops and you can tell the engine is working a little harder.

But the bottom line is, MOST of the time the car is moving, the fan will not be on, so there will be no extra drag.

 

i locate the sensor near the out let side not the in let side. this way it responds to how well the radiator is cooling. not how hot the motor is.

 

Jamie couldn't that have something to do with the computer engine management system though? Does that happen on a 71 Maverick, put more electrical load on the alt and have Idle drop? Is Idle dropping due to added physical resistance to the alternator or because spark is not as hot? Like I said though I am not an electronics guy, I'd like someone to explain to me how increased flow of electrical current can cause it to be harder to turn over an alternator. I speak from relative ignorance but would like to learn the princple that can cause this? Is it electrical resistance that causes physical resistance?

 

I always thought the idle dropped because the fan draws current away from the ignition making it harder to ignite the fuel at an idle until the engine is revved higher allowing the alt to make sufficient current to run everything.

I am pretty sure fans do draw quite a bit of current

 

would you...draw..this up for me? :Handshake
it needs to be so the ...light...won't be on if the fan...shorts...out to ground.


Frank

 

when running a genorator or alternator, power in has to be more than power out (conservation of energy, law #2). when the fan kicks on, there is more current draw from the charging system. supplying the extra current will make the rotor harder to turn; the opposing force is called 'back emf'. there is no such thing as 'free' energy, it all has to come from somewhere, and lots gets lost in convertions (chemical->mechanical->electical) has heat

i don't think that i has much effect on the standard ignition system because they are more volatage dependant than current dependant.

the gain, has i now understand it, is that the fan shuts off at highway speeds/ cool temps, whereas a standard belt driven fan will almost always spin and add resistance to the motor.

 

Good ol' entropy always strikes back straight to your face.

 

Doubt that there is more load on your alternator? ... loosen the belt to where it is just OK without a fan, then let the fan kick on and listen to it squeal ...

I had the same deal with my A/C on my daily driver, every time the A/C kicked on there was a belt squeal ...kept tightening the A/C belt, and the squeal wouldn't go away. It was suggested to me that it was the alternator belt ... tightened it up, squeal gone ...

 

Another gain is not having 5 large steel blades spinning around near your head and hands when you are working under the hood.

I was in the "thinking about it" stage, when a friend came over and I told him about it, and he said "I lost a buddy due to one of the blades coming off when he revved it and hit him in the neck".

Next day, I head off to the junk yard looking for a Taurus fan, and the guy that runs the yard says he TOO lost a friend to having a steel fan blade come off while he was under the hood messing with stuff.

Yes, there are still blades spinning under there, but they are hidden and you would have to almost "try" to get your fingers in there, and you never have to worry about your head or neck. And, on the thermostatic fan switch, mine is on only spinning maybe 1/4 to 1/3 of the time the engine is idling.

It was also nice to free up a few horses, even if it is a little harder on my alternator

 

Sure... Drew this up for another forum a while back, but it will do:


"A/C Source" would be connected to the wire that turns on your compressor, if applicable. I like to turn the fan on with the AC 'cause of the additional heat from the condenser, but mainly just 'cause it helps the AC work better. You could also use that for a manual override switch.

Anyway, the positive wire for the light would be connected to the same point on the relay that goes to the fan, and just ground the other side. This will tell you if the fan is getting power, if the relay goes out, etc. It won't tell you if the fan fails, but if the fan grounds out it should blow the fuse, which would also kill the light.

The part labeled "Temp Sw" is this thing. The relay is just a typical 5-pin. I used a GM fuel pump relay listed for a TBI truck.

 

the way i read this pic. is...the light will only tell you if the...fuse...blows.
the light will stay on no matter what happens past it.

...Frank...:Handshake