Curious what others think of installing a blocking diode to prevent AC Noise

[eddielee]

I have been considering installing a blocking diode for Alternative energy production to prevent AC Noise from screwing things up.

1600V*100A=160kW which is far more than our trucks output. This means that I could install it between the alternator and the power block to protect all electrical components easily and cost effectively. Installing a diode eliminates the possibility of AC current because it only allows current to flow one way. I would install it between the power block and the alternator then heat shrink to prevent electrical hazards.

Another option I have thought of is creating a diode bridge, however, it is difficult to find diodes with the capability of handling the current output. The only benefit to a bridge is that it would eliminate spikes due to having half of the AC wave. I don't think the average 1 max 2 volt spike will effect the electrical so much.

 

Have a look at what I am talking about

http://www.ebay.com/itm/1600V-Volt-100A-Amp-Wind-Turbine-Generator-Solar-Panel-PV-Stud-Blocking-Diode-/201025568109

[CSM]

It won't stop a spike.  If you have AC of some waveform coming out of your alternator, a single diode will make it a half wave.  A half wave is still AC.  Beyond that, the minor voltage ripples are bad but the big occasional voltage spikes and harmonics are the worst.  A single diode wouldn't stop these. 

I've thought about this a lot.  In my opinion, there isn't an easy, cheap, or safe way to fix this except doing it right with quality components.  You can go look at a bridge rectifier and compare how it works to what you are trying to do.  You can also look at band pass, high pass, and low pass filters.  Capacitors are typically used for low pass filters.  The amount of capacitance we would need to properly damp out all noise is actually quite dangerous.  

The one tool I do want though, is a cheap series of AC current warning lights that lights up at .01 .05 and .1 and 1 VAC sequentially.  However, I haven't figured out how to do that yet.  To add to this, I don't think an inexpensive sensor will help either.  Some sort of a transformer would be required to make it work and would require consistent frequency to work.  Even some cheaper multimeters don't pick up the AC that we have.  It took me borrowing and later buying a nice Fluke meter to get accurate VAC peak numbers from my broken alternator and other AC issue.

Edited January 1, 2016 by CSM

[Mopar1973Man]

CSM is right. Diodes won't work. I've seen several ideas for large Capacitors, coils and noise filter circuits. You'll still need to get back to the problem. Fix the damaged alternator.

 

[eddielee]

CSM, I am curious how much that alternator you wrote up actually cost. I like the fact that they are made in the USA. In my opinion that makes them worth more. Buying USA made promotes US economy...

 A bridge rectifier converts AC to DC and I do not exactly see a way to install one unless I open the alternator and reman it myself. Pull other parts and create my own bridge rectifier. Maybe it would be worth it, however, a lot of work and soldering...

It seems from what you are saying, if I want to protect the sensitive electrical from possible over current then I will need to install zener diodes  in the supply lines to the ecm, pcm and VP44 individually. The zener diode is used as a voltage regulator and will stabilize the voltage...

[Mopar1973Man]

6 minutes ago, eddielee said:

Maybe it would be worth it, however, a lot of work and soldering...

Why do all that... Just open in up and get a new diode pack from LarryB.

http://www.fostertruck.com/diode-pack-rectifier-bridge-for-dodge-denso-alternator.html

Takes less than 30 minutes to pull the alternator off the truck change the diode pack and reinstall. Super easy...

 

Edited January 2, 2016 by Mopar1973Man

[JAG1]

should carry those in the glove compartment.

 

Are there a lot of parts to watch when opening up an alternator? Or is it very easy like my tractor was?

Edited January 2, 2016 by JAG1

[Mopar1973Man]

No. Just small screws holding everything together. If I was going to make a alternator package I would do the brushes and the diode pack.

[CSM]

1 hour ago, eddielee said:

CSM, I am curious how much that alternator you wrote up actually cost. I like the fact that they are made in the USA. In my opinion that makes them worth more. Buying USA made promotes US economy...

 A bridge rectifier converts AC to DC and I do not exactly see a way to install one unless I open the alternator and reman it myself. Pull other parts and create my own bridge rectifier. Maybe it would be worth it, however, a lot of work and soldering...

It seems from what you are saying, if I want to protect the sensitive electrical from possible over current then I will need to install zener diodes  in the supply lines to the ecm, pcm and VP44 individually. The zener diode is used as a voltage regulator and will stabilize the voltage...

Call mechman.  The smaller 170 amp alternator I got was cheaper than their 210 or whatever.

Also, diodes of any flavor won't help in this DC system. Diodes would still allow half of the wave to make it through and you would be putting a ton of resistance in the system where it shouldn't be.  

I used mechman.  But I think moparmans ideas are also very good.  I kept my old alternator as a spare and will likely rebuild it myself.

Edited January 2, 2016 by CSM

[JAG1]

Don't brushes pop out making it harder to put back together?

[Mopar1973Man]

No. Really easy to install the brush ring. Small screwdriver to hold back the brushes and slip it over the slip rings.

[eddielee]

Using a DVOM what is an acceptable AC reading?

[Me78569]

less than .05 ac.  I think .02 is where most are happy.

[Mopar1973Man]

7 minutes ago, eddielee said:

Using a DVOM what is an acceptable AC reading?

Normal good - 0.01 to 0.03

Marginal - 0.05

Fail - 0.1

As for marginal it can be varied answer. Some vehicles can go well up to near 0.1 without a issue and other start having TQ Converter lock up issues as low as 0.04. Lower is best.

[eddielee]

So I have been having difficulties if I have a Bosch or Denso alternator.

What are the real tell tales? The Larry B's rebuild kits only cover Denso and say something about small wires going to 2 posts on the back.

I looked for Denso alternators and the ones I find look like mine. I also find Bosch that look like mine.

http://www.partsgeek.com/t11c86m-dodge-ram-2500-alternator.html?utm_source=bing&utm_medium=ff&utm_content=MP&utm_campaign=PartsGeek+Bing&gb=pp&utm_term=1999-2002+dodge+ram+2500+alternator+denso+99-02+dodge+alternator

Edited January 4, 2016 by eddielee

[CSM]

41 minutes ago, Mopar1973Man said:

Normal good - 0.01 to 0.03

Marginal - 0.05

Fail - 0.1

As for marginal it can be varied answer. Some vehicles can go well up to near 0.1 without a issue and other start having TQ Converter lock up issues as low as 0.04. Lower is best.

I would like to add that typically this is measured at idle.  I found with my bad alternator would get worse readings at higher rpm and on very hot days.  

[eddielee]

The reason I was looking into inserting one or more diodes is to protect the sensitive electronics in case the Alternator goes out of specs, not to replace the alternators diodes without repairing the alternator too.

Makes sense to me that if these electrical components are so sensitive to AC noise, then why not add a layer of protection. A zener diode is capable of doing just this, however, I have not found any large enough to carry the full load of the truck. Therefore, I would be limited to individual diodes for components.

Added resistance is not so much of an issue at the voltage and load of the components.

When Moparman says that some trucks failed with such a low noise volume over spec, I start trying to find ways to protect myself from such costly repairs using inexpensive sensible measures.

 

 

 

[CSM]

How is a zener able to do this?

[Cowboy]

Forgive me if I'm missing something, but I don't see why the extra diode wouldn't help.  the most common way (AFAIK) for main diode pack to go bad, is for one or more diodes to get slow, which means it doesn't react fast enough and lets some negative voltage out of the alternator.  A auxiliary diode in my thinking would prevent that from getting to the battery.  One thing I would be tempted to do, because everything gets it's power from the drivers side battery, have the alternator hook to the passengers side,  that will act somewhat as a RC filter.

[eddielee]

It doesn't seem to me that slight forward voltage spikes are bad.

The alternator has a variance in the first place.

A Zener diode is designed to regulate the supply voltage in power supplies, If I were to install one in the power supply line to the sensitive equipment with a value of 12V-13V it would only allow forward direction current and regulate the voltage fluctuation to the component. Stabilizing spike current and limit flow one way.

Just need to know the wattage and compensate, or minimize, for added voltage drop.

Edited January 6, 2016 by eddielee

[Cowboy]

You may want to double check your understanding about them.