It works....with one caveat. Dang.

Well, I got the throttle-actuator-solenoid gizmo all wired up and adjusted and it works! With one small problem. No matter where I wire it into my fan circuit, it won't disengaged as long as there is any current to it. Meaning, my fan, whenever it it turning (like when the car moves) will act as a generator and run electric current back to the battery. Even when the fan is off and it is slowing down to a stop, it is generating juice. Till it comes to a complete stop. Then the solenoid clicks off. Apparently, when this solenoid (from a TR8) senses any electricity, it stays on. Without getting into advanced electronics (diodes, etc.) my grand idea might well be an exercise in futility. I am so ticked. :madder:

TR6BILL said:

...Without getting into advanced electronics (diodes, etc.) my grand idea might well be an exercise in futility...

Click to expand...

Quantum physics is advanced, "diodes, etc" are just fancy plumbing. I sure some (I can almost guess which someones) on the forum can solve this with a part from Radio Shack.

Flux capacitor.

Interesting. Must be a really sensitive solenoid, if the fan is generating enough current to hold it in.

What does your fan control circuit look like? Possibly the easiest solution is to power the solenoid from the same source that triggers the fan relay. Or if you don't have a fan relay, add one.

Driving the fan through a diode would also work, but is probably not the best solution because there will be some power wasted in the diode (meaning the fan will get less). Also going to take a major power diode to handle the fan's startup current; and likely a heat sink to deal with the heat from the wasted power.

PS, is it just me, or has the BCF server been really cranky the last few days? It's taking me 2 or 3 tries for every post!

Doesn't seem to be my Inet connection, because everything else works fine.

It's not you alone Randall. My pipeline from the east coast is jammed at times too.

George had the answer a diode. I'm surprised they didn't supply one with the fan installation kit and relay.
It is installed in series and has a direction, in that it has to be installed considering the direction that the current flows.
This kit has a diode in the wiring.
https://cgi.ebay.com/ebaymotors/DERALE-FA...emZ330306874746

That is the simplest solution Bill and you can solder it in in minutes. One quick trip to Radio Shack and you should be good to go.

Wow, wind power on a six! Surprising how rotating magnets and a coil makes electricity.

Get the inline diode, Radio Shack has them for from 1-3 dollars.

Ray,

I've got to brush off my electronics here before I say the wrong thing. Ray, help me out on this. If I read this problem correctly, there is a small amount of voltage feeding back through the circuit, causing the switch to engage when Bill doesn't need it engaged.

But that same circuit is needed to allow the proper amount of current to power the switch when he does need it, so it can't be totally disabled.

Then Bill would need to know the amount of voltage coming back, to allow him to get the least resistance possible to block it, but not enough to block everything, correct?

The fan sending back current to the battery (and my indicator light for my fan) is an issue that I called Dan Masters about some time back. He was the one that informed me that indeed I was actually charging my battery, in a sense, when I was driving. The fan indicator light actually glows at speed, telling me the fan is spinning from air current. And charging my battery. Cool.

Not so cool, a diode will block the current in the wrong direction. That is, no way to shut it down, even though it is a weak current from the fan turning. Indeed I have a really good relay (Spal, same as Brosky) that actually has a blank #87 post, but this does me no good, same circuit. The fan, when I turn it off, actually keeps the solenoid open until it comes to a complete stop, so the current has got to be weak, but enough to trigger the darn solenoid. Unless I bypass everything and do the switch-on-the-dash-with-an-indicator-light thing. But that sorta kills the automatic response I needed. Any other suggestions?

Bill,

Mine is wired to either run automatically, with no light on the indicator switch, or manually, overriding the temp switch/relay and causing the light on the manual dash switch to come on. I was not there the day that Erik wired mine in, so I don't know how he has it connected in the series of the harness.

I do not have any indicator light for the fan being on, except for the manual switch light.

Probably the simplest thing, albeit not the least expensive, would be to replace the fan with one that draws less current while stll putting out over 2000 CFM. They're out there.

Or activate the solenoid that you have with a manual cockpit switch when you need it at idle.

Okay.. we have "reverse" current from th' fan feeding back to the solenoid's coil... "diode" is the first thing popping into mind.

Bill, can you post a rough schematic as to how the fan/switch/light/solenoid are tied into the electrical system?

Doc,

Read my post and tell me if I was wrong. I think that he needs a diode that will have some resistance, but not too much one way, with total resistance the other. If he reads the voltage coming back when the fan is off, but back feeding the circuit, he can determine what spec diode he will need.

I did, Paul. My feeble reasoning agrees. A resistance at the "flow back" side should allow the diode to be a one way "gate" without a need for more rig. And: Yup! Measuring the "feedback" current as the fan freewheels when off will be the part to determine diode spec's. Tho I s'pose as speed increases (and th' fan freewheels faster) the feedback current will as well.

I'd be for the easy way out and lose the light and all that, wire the solenoid and fan to the same relay (or trigger device) and roll on. If ya just GOTTA have a light to say the fan's on, think LED. Ancillary to the END of the run.

Allright, I just drew this out, let's try the KISS route first. If I could figure out how to post my drawing I would.

One way this is gonna work is to use a double pole relay, the solenoid goes on the second pole. This is the simpliest way of fixing this issue. Alternativly a second single pole relay would work, but to me that would clutter things.

The second way is with a diode. The diode would have to be installed after the relay, and after the connection to the solenoid. It has to be here, and now it's carrying all of the current of the fan. If I remember correctly, the fan draws on the order of 20 amps, so to have some room for heat, a 30 amp diode would be none too big, so Radio shack is out, they don't go that big, I just checked, you would have to use one of the big electronics suppliers, www.newark.com, or www.digikey.com to get a 30 amp 14 volt diode. You are also in the price range of a relay, 5 to 10 bucks.

One of the problems with this route is by the time you get a diode that big, you are into stud mounts and heat sinks with both sides of the heat sink being above ground electrically, which means that it needs to be isolated, no just fastening it to a handy piece of bracketry. Mounting it to the front of the fan might be an option, that way the air flow would keep it cool. I am assuming that it is a plastic fan and guard, no shorting issues.

Once a solenoid is pulled in you would be suprised at how little current is needed to keep them pulled in. On the order of milliamps.

Sorry to disappoint you Bill, but the fan isn't charging the battery, it's just lighting the light, there's no connection back to the battery with any of the switches being off. A diode in the line after the switch and indicator, heavy enough to carry the current of the fan, will prevent the light from coming on as the fan spins in the wind. Any diode in the line to the light, would keep the light off at all times.

Figuring out this kind of stuff is what I do for a living, so that's where I am coming from.

my money is on the two pole relay.

Steve, I've just been following this thread out of interest and learning some things, not that any of it applies to me, but would the double pole relay, prevent the spinning fan from activating Bill's high idle solenoid ?

yes, a double pole relay is two seperate switches actuated by a solenoid. the "goesinta" can be wired together to the supply fuse, one switch turns the fan on, the other switch turns the rpm bumper upper on. When the temperature sensor satisfies, ie the engine gets cooler, it turns off, which turns the relay off, now the switches are open and there is no physical connection between the three circuits, the fan, the solenoid, and the relay coil. I can't figure out quickly how to post a drawing.

An inportant point to note: is that the spinning fan would not activate his solenoid, only keep it activated once it was turned on. The current requirments after activation are 1/10 what you need to activate. My original reading of the post is that his idle came up at first heat then stayed there until he stopped at a traffic light.
Hope this helps