Sizing a capacitor?

Before you post any more, may I recommend the use of paragraphs to break up up acres of solid text. I find it virtually unreadable.

Graham

I would check for lack of ground straps. it sounds like you are created a current path through the engine block or radiator etc. the Sensors of the electronics for the controller maybe getting nulled out.

Run all the circuits off separate relays.

(snip)

Either the fan brushes or the speed control (probably a variable pulse duty cycle driver) are making radio frequency hash that is upsetting other sensitive electronics. Either you filter the fan wiring or you filter all the things that are being upset. I would start with the fans.

Look for one or a few clip on split ferrite bead that can be snapped around both fan leads (close to the fans). These will reduce the high frequency currents that travel back from the fan to the rest of the wiring harness and radiate all over the place.

The ones with a hole just large enough to pass the pair of wires will be most effective. If you can only find ones with a much larger hole, you might be able to wrap the pair around through the hole for a second pass.

This is what I am talking about:

If that helps but doesn't solve all problems, you can add more beads along the wire.

It might also help to add a capacitor across each of the motors, right at the fan, and also to add one from each terminal to the motor frame, but that is a lot more invasive than adding the beads, so it would be my second try.

agreed, inline filters are good suppressors for the pwm driving the fan, but shouldnt they be placed on the supply lines going to the PWM circuit rather than between the fan-pwm? the entire wire length is probably radiating all sorts of splatter emf everywhere. shortened and even shielded may help also.

or both places?

if possible, find some tech guy to alter the PWM circuit to prevent such drastic sharp rise times in the switch circuitry itself?

--- Please don't top post.

Even Google Groups advises against it.

From:

"Summarize what you're following up.

When you click "Reply" under "show options" to follow up an existing article, Google Groups includes the full article in quotes, with the cursor at the top of the article. Tempting though it is to just start typing your message, please STOP and do two things first. Look at the quoted text and remove parts that are irrelevant. Then, go to the BOTTOM of the article and start typing there. Doing this makes it much easier for your readers to get through your post. They'll have a reminder of the relevant text before your comment, but won't have to re-read the entire article. And if your reply appears on a site before the original article does, they'll get the gist of what you're talking about."

---

-- JF

Before you post any more, may I recommend the use of paragraphs to break up acres of solid text. I find it virtually unreadable. Sorry, will do.

I would check for lack of ground straps. It sounds like you are created a current path through the engine block or radiator etc. the Sensors of the electronics for the controller maybe getting nulled out.

The engine has a ground strap to the truck fire wall. The fan controller is grounded to the frame at a pretty good location. With the problem still there, I tried a new ground location: water meth controller was powered and grounded to a completely separate battery directly and the battery was not grounded to the truck.

Should I try a different place? Currently, since completely isolating the power and ground via a completely separate battery for the water/ meth did not work I have moved the fan controller ground, water/meth ground, and controller ground back to the radiator mount which is reported by truck owners as a very good place to ground to.

Run all the circuits off separate relays. There are no relays that I know of in the system. The water/meth controller is powered from a key on location for power. It was powered directly off a completely (second) separate battery. Neither location had any effect. The fan system doesn't have any relays that I know of. I believe the controller itself has the switching mechanism in it.

It might also help to add a capacitor across each of the motors, right at the fan, and also to add one from each terminal to the motor frame, but that is a lot more invasive than adding the beads, so it would be my second try. I'll try those magnet things. Any chance radio shack or some local store will carry them or should I order off the internet? Also, what size and type capacitors should I get? I have no idea.

using "reply to group", how does that constitute "top post"?

shielded

Typing your words above those you are replying to is top posting.

so i have to manually move my default cursor all the way to the bottom of the msg and then start typing? that will just wear me right out!

or should i set the > > using "reply to group", how does that constitute "top post"?

You are supposed to review the quoted text and clip out any parts that is not needed to remind others what you are replying to, before you post. It is customary to add in (snip) or 8< (scissors symbol) if you clip the last poster.

Then, you either insert your words directly below lines that you are reacting to, or post your entire message at the bottom. This is the standard for Usenet and just good manners. Remember, this is not an email reply to one person who knows what they have already said, but an archived post that is part of a conversation presented to the entire world, for anyone to join in. Normal capitalization, spelling and punctuation are also appreciated. It is hard enough to interpret many posts, without also having to decode slang and abbreviations. This is not a cell phone text message.

You are certainly free to do whatever you like, but if you can't be bothered to think about the effort it takes others to understand what you write, don't be surprised if many kill file you and never see anything else you ever post.

Bye bye.

John Popelish

Oh dear. Poor baby !

Graham

No to that, as it removes the context (ie people will not know what you are replying to)

Well explained John. But there is another point. If you are replying protesting at foul language or nasty posting (a regular perpetrator of which appears here occasionally) be careful not to requote his foulness as others may have kill filed to avoid his nastiness!

--- You seem to miss the point, which is that top posting is generally frowned on when replying to a USENET post, for many reasons.

You do know the difference between top posting, bottom posting and inline posting, don't you?

Peruse:

-- JF

ohh, such a short life to learn soooo much hoooey!

protocol, rigid social levels, strict grammatix, and so forth. just bores me to death............

Evidently, not yet.