VP44 PSG fuel cooler ideas

[snowshoveler]

My thoughts were to put the diode in but still check the alternator ( using your test ) once in a while.

Just a little extra protection.

I would never have thought about checking an alternator for AC.

But now that I read about it here it makes perfect sense, an alternator makes AC first and then its turned into the DC our trucks use. 

We still don't know if the AC pulse will kill it or even how much and for how long.

I would think that it dosen't take much and not for long either.

 Still learning and still asking questions.

Chris

[CUMMINSDIESELPWR]

couldnt one place a secondary component on the output of the alternator so it covers everything? still checking for ac noice between the secondary diode and the alternator, gives a second layer of protection so you have a chance to catch a failing alternator before it destroys components..

Edited August 21, 2014 by CUMMINSDIESELPWR

[Ilikeoldfords]

That would make sense to me. Even if you know your alternator is good and clean, there is never any telling when it will go bad. If you don't check it daily you are running the risk of damaging the other components. It would make sense to have that extra layer of protection in place and still check your alternator every once in a while.

[Mopar1973Man]

Ok. So how would you create a filter that can hold the max current flow of the alternator like during grid heater cycles in the dead of winter without burning up the filter itself? It would be the logical thing to do but can it be done? Could there be a filter device added to the charge lead of the alternator that would warn or disable the alternator if the output is to high in AC noise? Now its time for Yankneck to think on this one?

[MnTom]

Maybe one of these? http://www.amazon.com/NEGATIVE-DIODE-MOUNT-150AMPS-800VOLTS/dp/B00BF34BVU

[CUMMINSDIESELPWR]

Ok. So how would you create a filter that can hold the max current flow of the alternator like during grid heater cycles in the dead of winter without burning up the filter itself? It would be the logical thing to do but can it be done? Could there be a filter device added to the charge lead of the alternator that would warn or disable the alternator if the output is to high in AC noise? Now its time for Yankneck to think on this one?

 

the alternator will only put out a maximum of X amps at ~14vdc output, the current load/draw for grid heaters comes from the dual batteries, otherwise the alternator would work very very hard and have a short life.  so yes a filter can be made to match the maximum current output of the alternator or even a bit more as it wont be exceeded.  (make sense?)

[MnTom]

the alternator will only put out a maximum of X amps at ~14vdc output, the current load/draw for grid heaters comes from the dual batteries, otherwise the alternator would work very very hard and have a short life.  so yes a filter can be made to match the maximum current output of the alternator or even a bit more as it wont be exceeded.  (make sense?)

Check the diode I posted about. up to 800 volt and 150 amps.

[rancherman]

 

 

It would be easier to just remove the alternator and then there is no more AC noise issues period. Pure DC power solely from the batteries.

I was going to suggest a  delco  generator... but  I think they are 6 volt only...

[Mopar1973Man]

Be careful... If you place a diode in the line so positive DC will flow also the positive side of the AC waveform will still flow but negative side will stop. There is going to be more than a single diode. Remember it takes 2 diodes minimum to filter AC down to DC. 4 is called a full wave rectifier ans 2 is called a half wave. 

[KATOOM]

 

 

 

Oh I'm sure it not only controls those two solenoids but I'm betting the power surge during the starting process is higher than we think as the transistor acts as a capacitor and "I'm leaning" towards feeling like this is what dictates the start cycles.  Take that with a grain of salt too.....

[Yankneck696]

THe filter would probably weigh as much as the alternator to handle the amperage. I have designed many RF filters & I do know them well. It would be easier to just have a good quality rebuild.

And, as Michael stated, 1 diode will not wirk. Even a bridge rectifier needs filtering afterwards.

 

Ed

[MnTom]

Be careful... If you place a diode in the line so positive DC will flow also the positive side of the AC waveform will still flow but negative side will stop. There is going to be more than a single diode. Remember it takes 2 diodes minimum to filter AC down to DC. 4 is called a full wave rectifier ans 2 is called a half wave. 

OK, then why not get four of them and make something like this? 

This diagram is what is happening 60 times a second for converting AC to DC.

 

You would not have AC as an input, just what ever the alternator is putting out. The two AC inputs would be the alternator output stud and the battery negative,

[Yankneck696]

Again, a quality rebuilt alternator will do just fine.

 

Ed

[KATOOM]

Ya, I agree that alternator AC noise "could" be an issue but at this point I'm not convinced enough to rule out simple power surges during start cycles and the heat generated during those spikes of juice.  I'm not sure there's reason to think all of our alternators are junk.

 

Look.....if there's anything we know, (and taking it with a grain of salt too) we do know that "heat cycles" are supposedly a recognized issue with the PSG.  So obviously it would seem that someone somewhere has deciphered or come up with that there's something going on in the PSG during that moment in time when starting the engine causes the Pb free solder to crystallize.  Is it the fact that the PSG is already hot and then the spike of amperage is enough to overheat the solder joints or is starting the truck at any time abuse to the PSG solder?  For whatever reason, some VP suppliers will discuss "heat cycles" and some will discuss "start cycles".  Are they one in the same and simply a confusion of language?  There's those of us who are seriously considering that the heat soaking is a major issue here and I'm not ruling that out.

 

Anyways, when we're talking about start cycles I think its very important to remember this older article: http://www.farmshow.com/view_articles.php?a_id=646

 

The guy in that article has (had) more miles on his 2000 Dodge Cummins than most people will ever drive every vehicle they've own combined.  But more importantly to note in the article is that the truck has gone through many lift pumps and other things.....but NEVER changed the injection pump.  Again.....NEVER changed the injection pump.  He has some custom built injectors and some unknown HP box claiming the truck makes around 300 hp.  Now in knowing this.....and assuming the old guy isnt lying since he has no reason to lie.....you have to consider what hot shot drivers do.  They drive and drive a lot of miles and the amount of shut down times in relation to those miles driven compared to any of us daily driver guys is going to be nowhere close to the same.  Even you Mike.....  You live in an area where you say its an hour or more just to go shopping for the basics.  That means most likely your shut down times in relation to the miles driven are going to be a lot different than those daily drive guys as well.  Maybe this is why you have 200k on your VP.....and I'm sure how you treat your truck helps too.  But nonetheless, its a well worth point to be made.

Edited August 22, 2014 by KATOOM

[Mopar1973Man]

OK, then why not get four of them and make something like this? 

This diagram is what is happening 60 times a second for converting AC to DC.

 

You would not have AC as an input, just what ever the alternator is putting out. The two AC inputs would be the alternator output stud and the battery negative,

 

This exact configuration is on the back of the alternator now. (Full wave rectifier). So if you put this on the charge lead there would be zero or very little voltage would be at the far side. Why? Because you only see the rectified AC already rectified DC. So if there was 0.1 AC noise from the alternator the output now would be 0.1 DC volts.

[rancherman]

I'm  putting this altogether in my head now...

 

Katoom    compared this  transistor to a  capacitor (there is  a  field)       So      when  a    charged  vessel  is  'hit'  with  a    shot  of    reverse polarity  (dirty  AC)   no matter how  quick  or   small,  it's  the  same effect as  a  short circuit...  however  small and also quick.. 

 

Mike,   on the above diagram,    one leg (+) would  have  our  13.5 volts dc plus  0.1 ac  right off the   alternator... the (-) leg  would have the other side of the   0.1v  AC.    

 

how  can  it not allow the  13.5 to pass  (or whatever the  output is?)    but  only  .1v DC?     

Edited August 22, 2014 by rancherman

[Yankneck696]

Also, every diode (Or bridge rectifier) drops voltage 1.3 or 1.6 volts. Now, how would you connect the ground casing to the casing of the alternator, then back to the negative part of the wiring system, as the casing is grounded?

I understand that you are trying to find a way to work around the issue & applaud your tenacity.

I have been a Ham radio operator, electrician, designed & built solder reflow machines that were powered by RF energy. My electronic days started with tubes.

 

My honest guess about the alternator issues is that:

1. the packaging requirements do not allow enough heat out.

2. Cheap rebuilds all have Cheap Chinese diode/rectifier packs.

3. our truck's wiring system was marginal at best when designed (Bean counters) & after 15 or so years are deteriorated, due to heat, corrosion & of course vibration.

 

I worked in the auto electric field for a while & usedd to rebuild alternators & starters for the most reputable shop in the Boston area. We used the best of parts & ran every alternator through a full load test, along with hooking them to an oscilliscope to check for AC leakage & to make sure that the brushes were broken in. I called the owner in January & was talking to him about the issue & he stated "Eddie, I just cannot afford to build an alternator with the right parts anymore. Rectifier packs of any quality cost more than 1/2 of what I can buy a Chinese alternator for. So, now, I am just a retail outlet, except for SOME heavy equipment starters. Otherwise, I would have to close the shop down".

For our truck, specificly, he purchases the alternator for $34 & sells them for $88. The good american rectifier pack costs $28 by the 100. The brushes, media blasting of the case, machining of the commutator s, testing of windings, brushes & man hours would put him right out of the market.

 

Keep shoping at Walmart.....

Ed

[Yankneck696]

Heck, back in the 80s, a Leese Neville 350 amp alternator was over $700. It was the industry standard for fire engines & other heavy electricly loaded vehicles. My former boss buys them SHIPPED from China for $270. What does that tell you?

 

Ed

[rancherman]

Amen to  the  high dollar  leese Neville!    whoever  imagined a  cast iron  alternator?????    I  had  one on a combine 2 years ago..    it was  ONLY  a  150 amp,  but  they wanted  825 bucks !      say the least,    a  delco  now  resides there.

 

Like  I said  many many posts ago,   I be  really surprised if  Bosch  built those boards  in-house.     They had to been   low bid   supplied..

[Yankneck696]

I'll clarify. THe 350 Leese Neville was $700 cost to the shop brand new. Sold for around $1200.

 

Ed