Herzog

somewhat damaged
Admin
Location
Wydaho
How does using a solenoid (relay) reduce the start-up draw?

Honestly I'm not sure. I just know that using the fan with a solenoid doesn't tax the electrical system as much as if you were to wire it with a regular relay. I am solenoid-tarded but they do work. I suppose it's because they are designed to handle a more amps?

Hoping somebody with some DC experience will chime in as to why. :D
 

ricsrx

Well-Known Member
If your fan pulls 20 amps and you dont use a relay, all of the wiring and control devices (temp switch, on/off switch) have to be rated for 20 amps because the full current draw of the fan will go thru the devices to get to the fan.

if you use a relay, power comes from the battery thru a fuse to the relay then to the fan. the relay has a coil that draws a fraction of an amp so all of your devices and wire will only have to be rated for the draw of the coil (1 amp) not the fan.

just my 2 cents
Rick
 
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Corban_White

Well-Known Member
Location
Payson, AZ
Thanks Rick. I am actually pretty well versed in DC (as well as AC) and understand those principles. For my day job I wire industrial electrical control panels. That is why I am having a hard time understanding how a relay rated for a bunch of amps (solenoid) can function like a soft start. However, I already know that my foot doesn't taste very good ;) so if it really does work I would like to know the principle behind it rather than coming in here and calling BS. :)

Not trying to hurt any feelings here, just trying to understand.
 

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
It doesn't act as a soft start, but it could possibly get the fan up to speed faster (spending less time in the initial heavy-amp-draw startup part) since it can provide more current. In that way it may seem to be easier on the charging system, since you won't notice it loading the alternator on start?

I'm just guessing.
 

Herzog

somewhat damaged
Admin
Location
Wydaho
It doesn't act as a soft start, but it could possibly get the fan up to speed faster (spending less time in the initial heavy-amp-draw startup part) since it can provide more current. In that way it may seem to be easier on the charging system, since you won't notice it loading the alternator on start?

I'm just guessing.

Yes, that's exactly what I was getting at... just didn't say it as well as you did.
 

waynehartwig

www.jeeperman.com
Location
Mead, WA
It really is. I didn't realize how over-board with tubing I went on this rig until it was time to flip it and weld it. I guess that's what happens when you get shacked up in cold garage for too long.

It does look like a lot. What does it weigh (guess)? ...IMO too much tube is better than not enough. It looks hell for stout, too! Should be able to hold up to a 100 mph wall crash :D
 

sLcREX

Formerly Maldito X
Location
Utah
I just got through reading and browsing this thread for the past few hours, very awesome fab work! I'd love to check this out sometime :)
 
R

rockdog

Guest
It doesn't act as a soft start, but it could possibly get the fan up to speed faster (spending less time in the initial heavy-amp-draw startup part) since it can provide more current. In that way it may seem to be easier on the charging system, since you won't notice it loading the alternator on start?

I'm just guessing.
Basically the tauras fans pull huge amps on startup. I run mine through two 45 amp relays run parallel. Mines now only a one speed fan. So 90 amps can run to the fan at one time. Pretty much the same way Shane is running his. I ran relays because they were rated to run current for long periods. (Sounds like solenoids can too from Shane's experience) The relay or solenoid is being triggered by a thermal switch (sensor) in the engine coolant. It sends a small current through a small wire to the relay. Basically acting like an on off switch for the relay. Thus opening and closing the big juice wire to the fan.
I tried running a high dollar programmable Spal controller on my tauras fan. It literally melted frying my fan with it. It just couldn't take the huge amp draw these fans pull.
 

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
These are 85A continuous-duty solenoids, the more common starter solenoid is not rated for continuous use.

My personal preference is to wire the solenoid trigger to an ignition-switched source, so the fan is on if the ignition is on. I've had thermostatic controls fail more than once, threatening to fry my motor when the fan didn't run.
 
R

rockdog

Guest
These are 85A continuous-duty solenoids, the more common starter solenoid is not rated for continuous use.

My personal preference is to wire the solenoid trigger to an ignition-switched source, so the fan is on if the ignition is on. I've had thermostatic controls fail more than once, threatening to fry my motor when the fan didn't run.

No way I want to listen to that noisy fan all the time. I carry an extra thermostatic sender with me. Plus I can actually watch the temp gauge drop while the fan is running. It will go from 200 degrees to 185 in about 45 seconds.:eek:
 

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
No way I want to listen to that noisy fan all the time. I carry an extra thermostatic sender with me. Plus I can actually watch the temp gauge drop while the fan is running. It will go from 200 degrees to 185 in about 45 seconds.:eek:

They do kick ass. :D I've never actually needed to us High speed on them, only Low...it moves plenty of air for anything I've ever needed, and the sound is less that way.

If I had bucks, I'd use one of the DC Current Controls speed controls for it...turns it into an infinitely-variable-speed fan, only running as fast as it needs to, to maintain a temp.
 

Herzog

somewhat damaged
Admin
Location
Wydaho
looks good brother. you plan on powdercoating it? that would uber-sweet:cool:

Hey, it says "non-bling" at the bottom. I need to stick with my standards.

I plan on blasting it and just rattle canning it. I change stuff way too much to make use of powder.

Also forgot to post up, fan is a perfect fit for my radiator. Part #'s are somewhere in this thread if somebody needs to do the same.

attachment.php
 

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Herzog

somewhat damaged
Admin
Location
Wydaho
Electric stuff. Switches, relays and various parts.
IMG00441-20110403-1032.jpg

Other misc parts, including some Summit Machine drive flanges. :cool:
Hood hinges, carrier bearing for driveline.
IMG00442-20110403-1033.jpg

Detroit & 5.38 gears for the front.
IMG00443-20110403-1033.jpg

Yukon 35spl outers
IMG00445-20110403-1037.jpg

I used to be a D44 guy so this photo is neat to me. 30 spline outers vs 35 spline.
I wish I had some 19 spline d44 outers to compare. :rofl:
IMG00446-20110403-1039.jpg
 

Herzog

somewhat damaged
Admin
Location
Wydaho
Complicated interior / pan all welded up. Also changed the engine overhead bars slightly.
IMG00438-20110402-2208.jpg IMG00451-20110403-1736.jpg IMG00447-20110403-1734.jpg

Rear axle: added some gussets to the tabs.
IMG00448-20110403-1735.jpg IMG00450-20110403-1735.jpg

Coil-over mounts on the chassis w/ a little primer.
IMG00452-20110403-1737.jpg IMG00453-20110403-1737.jpg

Making good progress. TONS of small stuff taking up hours of time making the progress feel very slow.

Greg stopped by today and lent a hand and shared some music. :D Thanks for coming by! It was good to hang out for a while.
 

Gravy

Ant Anstead of Dirtbikes
Supporting Member
Nice pile-o-parts :D
When you assemble those outers make sure the Yukon stub doesn't extend too far past the drive flange.
I had to shave 1/8" off my stubs down to get the cap bolted.

edit: here's my old d44 shaft vs. 35 spline yukon stuff
100_1904.jpg
 
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