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Fixing a PWM DCC Fan Controller

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Old 10-16-2007, 06:35 AM   #61
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Forgive me for being just smart enough on this stuff to break things (and far too stupid to know that I'm about to break something), but isn't impedance the AC equivalent of resistance in a DC circuit?

Yes it is, and it depends on the frequency too, wires get funny at higher freqs, which is why a/c power here and in Europe is in the 50-60 hz region.....aircraft with their shorter power runs typically use 400 hz (cycles).....when you get into power switching type things like this PWM controller, I am shocked that any external transient on the power line would toss it off ANY, let alone blow the thing up....

BTW, I too lazy to go back to where EVER and find my post on that old thread, think it's deleted anyway, but if I mis spoke I"m sorry, I meant that ~40 amp fuse to be in the power line of the controller, NOT the alternator output stud....that is handled by the fuse link and the fuse block under the dash....

which renders Baskins' comments above totally moot.....

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Old 10-16-2007, 07:57 AM   #62
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First off get the abbreviation right PWM as in Pulse Width Modulation, can you say that?

Yes I can say that. I know it's PWM and what it stands for and with the exception of a typo here and there that's what I always insert. Thanks so much for your time.
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Old 10-22-2007, 09:20 AM   #63
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Sorry to be out of this thread but why don't you make this wiring for you Fan ?



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Old 10-22-2007, 10:00 AM   #64
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Hey Jerome. The reason is just because I wanted variable speed. This means that when the fan doesn't need to be spinning at full power it won't be. This keeps the noise down, fan motor wear is down, and is used less power.

I have had fans wired with relays before and it works just fine...I just want variable speed.
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Old 10-22-2007, 03:12 PM   #65
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Hi DB,

I dont get all this arguing on YOUR thread by OTHERS!!

It seems you have a problem. The guy doesn't want to or simply won't help. Personally I wouldn't buy from him again.

I once fried a new £700 ($1400) Clifford alarm by trying to wire in my missing cigarette lighter. Shorted out, spiked through starter loom and fried the controller of the alarm. MY FAULT but he changed it. Why? Who knows? I have given him plenty custom since.

My point is regardless of fault, support is essential and you aint getting it. Look elsewhere bud, you will find a new solution to what you want to achieve unfortunately at your cost but what can we do....

Best of luck hope you work it out
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Old 10-22-2007, 03:30 PM   #66
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Thanks friend. I have spoken with Brian a few times since these threads all settled down and I am shipping it to him to have him look at it and maybe fix it. If it's salvageable then great cause I will be happy to use it. If not, I have alternatives but none I liked as much as this controller.
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Old 10-22-2007, 04:37 PM   #67
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The soft start feature is nice, too...especially when you're running a fan with a 105A startup spike.
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Old 10-22-2007, 07:48 PM   #68
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A relay and temp sender. What $15.00 and less grief. And they have been around for decades. Who gives a hoot about variable speeds.
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Old 10-23-2007, 12:42 AM   #69
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Originally Posted by Durango_boy View Post
Thanks friend. I have spoken with Brian a few times since these threads all settled down and I am shipping it to him to have him look at it and maybe fix it. If it's salvageable then great cause I will be happy to use it. If not, I have alternatives but none I liked as much as this controller.
Get one of his filters for $10 if the controller is repairable.

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A relay and temp sender. What $15.00 and less grief. And they have been around for decades. Who gives a hoot about variable speeds.
A good number of the modern car manufacturers. The Mk. VIII is a variable speed fan in it's native vehicle.
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Old 10-23-2007, 08:44 AM   #70
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The soft start feature is nice, too...especially when you're running a fan with a 105A startup spike.
Sorry, for saying this Sam, but I thought you guys were crazy for using it in the first place. Startup current spikes of that magnitude are always a challenge. At least the Dual Spals divide the problem in two, and provide an inherent 2 speed configuration.

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Get one of his filters for $10 if the controller is repairable.
I don't understand why this system filter wasn't designed internal to the basic controller. Probably the fix for the initial design configuration. Baskin should include it from the get go. It would save all kinds of headaches.

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Old 10-23-2007, 02:33 PM   #71
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Sorry, for saying this Sam, but I thought you guys were crazy for using it in the first place. Startup current spikes of that magnitude are always a challenge. At least the Dual Spals divide the problem in two, and provide an inherent 2 speed configuration.
I'm pretty sure the Lincoln electronics have a PWM controller for the fan built-in somewhere.

There are a lot of people (not just with Corvettes) running the Mk. VIII fan in all sorts of custom configurations. It just takes a bit of clever wiring...and it moves some serious air. Two relays each carrying half of the load seems popular - I think I'm going to rig mine that way for an override system.
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Old 10-23-2007, 03:59 PM   #72
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My cheap, simple, stock cooling and charging system is looking better everyday.
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Old 10-25-2007, 03:09 PM   #73
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Originally Posted by Bullshark View Post
Sorry, for saying this Sam, but I thought you guys were crazy for using it in the first place. Startup current spikes of that magnitude are always a challenge. At least the Dual Spals divide the problem in two, and provide an inherent 2 speed configuration.
People use it because it's far quieter and it uses far less current for the same airflow.

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I don't understand why this system filter wasn't designed internal to the basic controller. Probably the fix for the initial design configuration. Baskin should include it from the get go. It would save all kinds of headaches.

Bullshark

No, I shouldn't, it's an expensive part, I'd have to make the box larger to fit it, less than 5% of the cars need it, and it takes less than 10 seconds to install, in fact if it's ordered with the controller, it's installed before it ships.

If this is a reference to the controller that was damaged, any decent engineer would tell you that if the filter was installed, the controller would most likely be unrepairable at this point and he could tell you exactly why. He would also tell you that it has very little to do with the controller, but rather its effect on the alternator itself. Again, there's a reason that me, spal, and all of the automotive manufacturers choose not to connect these to the alternator and it's not because we don't understand what you do, it's because we understand what you don't.
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Old 10-25-2007, 05:04 PM   #74
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Again, there's a reason that me, spal, and all of the automotive manufacturers choose not to connect these to the alternator and it's not because we don't understand what you do, it's because we understand what you don't.
the problem is evidently you don't really understand it either.

Black Magic.
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Old 10-25-2007, 05:38 PM   #75
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The fact of the matter is that I understand it very well, as anyone who has taken a basic control system class would. Does this mean that could explain it to you? I get several groups of people as customers, one of them tends to state that they know nothing about engineering. Is that group a problem? Absolutely not and for two reasons, first, they deal with reality in that they don't spend their lives pretending to be something that they're not and second, they're generally more intelligent than those who do, so they're easily teachable

Now you claim to be an electrical engineer, but make that claim with the writing skills of an elementary school student, moreover, in your little thread on the other forum, you clearly demonstrate that you donít even comprehend the concept of inductance. Well it turns out that you have to graduate from high school to attain an electrical engineering degree and anyone who has done that understood the concept of inductance before the end of their second semester there. You really ought to give that up, I donít think anyone is buying it here, it just makes you look foolish. The bottom line is that a guy like you who spends his time and effort attempting to impress people with what he doesnít know will never learn anything, because youíre essentially unteachable . Could I explain it to DB and IB ? Absolutely, I could teach them and in fact the majority of the people here in minutes what it would take you a lifetime to learn.
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Old 10-25-2007, 08:58 PM   #76
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Now you claim to be an electrical engineer, but make that claim with the writing skills of an elementary school student, .
Any engineer worth a damn can't spell or write. If you were one you'd know that.

Again all we get out of you is gibberish. You refuse to give us a technical argument because you have no clue.

You probably copied a design out of a book. Scratch that. If you copied someone else's design it would probably work.

P.S. Speaking of the thread on the other forum. Its funny you fail to mention that in the thread at least 6 EE's agree that your controller is a smoke bomb.

Last edited by turtlevette; 10-25-2007 at 09:28 PM.
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Old 10-25-2007, 09:27 PM   #77
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Any engineer worth a damn can't spell or write. If you were one you'd know that.

Again all we get out of you is gibberish. You refuse to give us a technical argument because you have no clue.

You probably copied a design out of a book. Scratch that. If you copied someone else's design it would probably work.
So, your claim is that an education makes a person illiterate ? Thatís classic !

As I said, any of my customers can ask me, but just as with your little buddy mr vette, Iím not going to sit here and pretend to have a technical discussion with you when I know very well that it would be akin to attempting to teach a monkey to read sheet music, again, as I said, a pretender is invariably unteachable due to the simple fact that you have to deal with reality to learn. I have an idea, why donít the two of you get little cowboy and indian outfits and pretend to be that instead of engineers, at least giving advice on how to make corn meal wonít damage anyoneís car.

Itís a patented design and it turns out that you canít patent someone elseís design. Try and keep up.
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Old 10-25-2007, 09:51 PM   #78
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It’s a patented design and it turns out that you can’t patent someone else’s design. Try and keep up.
i could take a dump and patent it. So what?

looks like you patented a pile of hooey.
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Old 10-25-2007, 10:25 PM   #79
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No, a patent requires that the invention is unique, has utility, and is functional, so although your dump may very well be your greatest accomplishment, it’s not patentable, but thank you again for demonstrating to us that you’ve never worked in any field of engineering.

DB and IB, here you go, I used my fancy new CAD program for the drawings.

The first thing to understand is how an alternator regulates its voltage or, more accurately, its output current. The armature is generally wound on the housing of the alternator, and depending on the amount of turns of wire in the armature, the speed at which a magnetic field passes by it, and the strength of that magnetic field, a current will be induced in those windings. The AC voltage is then rectified in order to derive a DC voltage byway of the bridge rectifier..

The voltage regulator then compares the output voltage to an internal reference, if the output voltage is too low, it will raise the voltage to the field windings, raising the magnetic field produced, which raises the current output of the armature and, thus, the output voltage for a given load. if the output voltage is high, the regulator will lower that voltage, lowering the output current. Understand the following equation v= L di/dt and more importantly, its integral for a step function; I = vt/L , it describes the current (I) through an inductor (L) over time (t) as a voltage (v) is applied. Notice the waveform below, it represents the field current verses the voltage from the regulator into the inductive field windings of an alternator:

…….._______
……..|……..…|.…..……|.
Vin…|…….….|…...……|
……..|………..|…...……|
.…….|………..|______|

………..…….../\
.………..……/.….\
Iin……..../..….....\
……….…/.……....….\
………./…………........\/

Time ---------------->

Notice that the current lags the voltage by 90 degrees. Now, the equation for voltage on a capacitor is represented by the equation v = It/C Notice the same ramp and phase lag into the current driven capacitor as was shown with the voltage driven inductor

…….._______
.…….|………...|.………..|.
Iin….|.………..|……...…|
……..|………...|…...……|
……..|………...|______|

…………...….../\
.…………….../.…\
Vin…......./..…...\
…………../.……...….\
………../………….......\/

Time ---------------->


One thing to note is that as the frequency of the input signal increases, the magnitude of the resulting signal decreases. So, let’s connect the dots, the regulator reads the output voltage and adjusts the field current accordingly after some time delay. This then adjusts the output current of the armature, and if a capacitor is attached to the output of the alternator, a second time delay is produced, if it is large enough, it will produce a time delay near that of the field winding and the product of those signals will not be diminished past the sensitivity of the voltage regulator. So what happens? Well, at some frequency, each of these circuits will delay the control signal by 90 degrees, for a total of 180 degrees, so the field current doesn’t increase with a lowered output voltage, it instead decreases, it doesn’t decrease with a raised output voltage, it instead increases. In other words, the total phase shift through the circuit is 360 degrees (the regulator inverts, giving a 180 degree shift), providing positive, in lieu of negative feedback, the theoretical minimal phase shift for oscillation is just over 270 degrees, and it will always oscillate with a phase change between 270 and 360 degrees. What has been constructed, essentially, is a 1.5KW power oscillator, that’s why no one tries to filter the output of the alternator upstream of the field sense wire and is therefore why no one attaches electronics that need to be filtered directly to the alternator output. http://www.sss-mag.com/cosc.html#theory


....................................capa citor
.______...........................______ _
|……...…|…………............……|…..….…|
|.…I…...|----------------->|.-90....|
|______|……..………..........…|______|
….../\.……….................……………|
…....|….……………….................…|se nse
.___|__…………….............…..__\|/.__
|……...…|….……...............…|……...…|
|..-90….|<----------------|...180…|------.reference
|______|……………..............|______|

field


So, what limits the size of capacitor that can be attached to the alternator? Well, in order to oscillate, the loop gain has to be greater than 1, the ratio of the alternator output current to the regulator error voltage is about 100A / 10mV @ about 100 Hz, depending on the design. At 10 times that frequency, it will be 10A / 10mV and will decrease linearly with frequency. In practical terms, nothing is a pure current source or voltage source, even a battery will drop some voltage with load and the best current source won’t drop the voltage in exactly half as the load is doubled. If the capacitor attached has a significantly higher impedance than the armature winding at a frequency where the field winding has a significant response, it won’t oscillate, because it won’t provide a high enough phase change. It’s also dependant on how far the battery is from the capacitor, since that inductance will typically provide a small phase change and isolation between the capacitor and the battery. Notice also, that, even without the capacitor, a periodic load upstream from the sense wire will cause the alternator output to ring due to the 90 degree phase change provided by the field winding.

QED, later.

Last edited by baskin1; 10-25-2007 at 11:27 PM. Reason: put a leader in front of the term "capacitor"
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Old 10-25-2007, 11:35 PM   #80
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That was most informative.
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