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Alternator vs Generator and Overvoltage

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ChangDriver

Joined: 15 Sep 2007
Posts: 266

Posted: Sat Feb 16, 2008 6:36 pm Post subject: Alternator vs Generator and Overvoltage

Gang:



Can Brian or someone enlighten me on this topic.  From what I recall, both gen and alt systems can have an overvoltage situation.  The external regulator is supposed to control this.  From what I gather, the CJ/Yak electrical system does not provide protection for this?



Please enlighten me!



Craig

brian-1927(at)lloyd.com
Guest

Posted: Sat Feb 16, 2008 10:45 pm Post subject: Alternator vs Generator and Overvoltage

On Feb 16, 2008, at 6:36 PM, Craig Winkelmann, CFI wrote:



 	  Quote: 	
		   

 >



 Gang:



 Can Brian or someone enlighten me on this topic.  From what I  

 recall, both gen and alt systems can have an overvoltage situation.


	


That is correct.



 	  Quote: 	
		   The external regulator is supposed to control this.


	


No, not necessarily unless the regulator specifically has OV  

protection. Most standard regulators do not. Spam-can electrical  

systems typically have a separate OV protection relay that sits  

between the regulator and the field circuit of the alternator. If the  

voltage goes too high the OV relay disconnects the field circuit thus  

shutting off the alternator.



 	  Quote: 	
		   From what I gather, the CJ/Yak electrical system does not provide  

 protection for this?


	


I believe that the Yak has an OV relay but the CJ does not. I got Bob  

Nuckolls to cook up an OV protection circuit for the CJ that will pop  

the field circuit breaker and turn on an OV warning light. Its  

installation is relatively simple. It must be wired to the main  

electrical bus to sense the voltage and it must be wired to the field  

circuit between the existing regulator and the generators field  

winding. If there is an OV event, it disconnects the field circuit  

thus protecting the rest of the electrical system.



 	  Quote: 	
		   Please enlighten me!


	


Does this help?



--

Brian Lloyd                         3191 Western Drive

brian HYPHEN 1927 AT lloyd DOT com    Cameron Park, CA 95682

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

— Antoine de Saint-Exupéry



PGP key ID:          12095C52A32A1B6C

PGP key fingerprint: 3B1D BA11 4913 3254 B6E0  CC09 1209 5C52 A32A 1B6C

ChangDriver

Joined: 15 Sep 2007
Posts: 266

Posted: Sun Feb 17, 2008 9:44 am Post subject: Re: Alternator vs Generator and Overvoltage

Brian:



Yes it does.  As I have a significant investment in avionics in my CJ, I am not interested in cooking them with a potential overvoltage situation.



You mentioned that you would automatically replace the gen system and replace it with an alternator in any Yak/CJ you owned.  I suspect it is more for the peace of mind in modern regulators/alternators/etc. or is there another benefit of the alternator that I am missing (other than weight).



Also, I have not seen an alternator for the CJ on the B&C website.  The one listed is for the M-14 not the Housai.  I understand that the drive spline is different on these two engines.



Thanks for your help,



Craig

brian-1927(at)lloyd.com
Guest

Posted: Mon Feb 18, 2008 7:35 am Post subject: Alternator vs Generator and Overvoltage

On Feb 17, 2008, at 9:44 AM, Craig Winkelmann, CFI wrote:



 	  Quote: 	
		  You mentioned that you would automatically replace the gen system and replace it with an alternator in any Yak/CJ you owned.  I suspect it is more for the peace of mind in modern regulators/alternators/etc. or is there another benefit of the alternator that I am missing (other than weight).

	


Oh, be careful when you ask me a question. You may get more answer than you want.  More below.



 	  Quote: 	
		  Also, I have not seen an alternator for the CJ on the B&C website.  The one listed is for the M-14 not the Housai.  I understand that the drive spline is different on these two engines.

	


I am not sure that the drive spline is different (Dennis?) but I do know that the Huosai engine has the shaft seal in generator case rather than in the engine accessory case as is more common. The M14 has the shaft seal in the accessory case. I have seen several alternator conversions where someone makes an adaptor plate with the necessary shaft seal for the Huosai engine. Most involve truck alternators with the proper spline shaft welded to the alternator shaft and then inserted through the adaptor plate.



As for alternator vs. generator, here goes the short and the long of it.



Short version: 



If your airplane already has a stock generator and it is working, leave it alone until it breaks. A working generator will do the job just fine. If you have a broken generator or are doing a ground-up restoration (as I am) you may want to consider an alternator conversion, especially if, like me, you have completely removed and discarded the stock electrical system. (Just the wire loom from a CJ6A weighs 100lbs, mostly due to the 100% copper braid shield covering every inch of the cable bundles.) If you want to add an OV protection system, do so. Basically it will wire to the generator switch and between the existing voltage regulator and the generator.



Long version:



Generators are a lot more complex than alternators. Since the alternator has relatively few parts so I am going to describe it first. After that I will describe all that has to be added to make a generator and how it adds to all the interesting ways a generator can fail.



An alternator has relatively few parts. First, there is the case. This normally consists of two aluminum end pieces with a steel part in the middle (more on this part later.) The shaft which transmits the mechanical power from the engine to the alternator is supported by bearings at either end of the alternator's case. On the shaft is the armature which consists of an electromagnet of a single winding. This winding is the field. Current for the field is provided by the voltage regulator (more on this later) through a pair of brushes and slip rings. The slip rings are just round contacts that rotate with the armature. The brushes press against the slip rings to transfer electrical current to the armature. When more current flows in the field, the armature produces more magnetism. Less current means less magnetism.



The center section of the alternator's case is a complex steel pole piece. The three stator windings which produce the electrical power output are wound on this pole piece. There are six diodes which "steer" the power from the three stator windings. The negative side of the six-diode array is usually connected to the alternator case. The positive side of the diode array is connected to the battery or B-lead. The diodes convert the alternating current from the stators into the direct needed by the electrical system. They also serve to prevent current from flowing through the alternator when its output is less than the battery voltage. This is why an alternator's B-lead is always connected to the battery in a car's electrical system. No on/off switch is needed.



The output of an alternator varies depending on two things: the current in the field and the RPM of the armature. The if field current is held constant then the output of the alternator will increase as RPM increases. Since we want constant output, something needs to adjust the field current. That is the job of the voltage regulator. The voltage regulator always assumes that the alternator is turning. When the voltage on the bus is too low it increases the field current (up to some maximum, usually about 3-4A). At low RPM a lot of magnetism and a lot of physical force are needed to generate power so the field current is high. At high RPM the opposite is true.



If the load on the alternator is increased, e.g. someone turns on the landing lights or pitot heat, more output is needed from the alternator. The VR sees the drop in bus voltage and increases the field current until the voltage is again at the proper level. Reverse that if the load is decreased.



That is how an alternator works.



BTW, an alternator is protected from delivering too much output by the resistance of the stator windings. Bottom line is that a 60A alternator can't deliver more than 60A so it is self-protected. (The reason for making this point will be made clear later when describing the generator.)



Only two things kill an altnernator: mechanical wear and heat. There are only three wear points in an alternator: the bearings, the slip rings, and the brushes. Since the brushes are made of carbon and the slip rings are made of copper, almost all the wear is on the brushes. Keep feeding the alternator new brushes and it will last almost forever, modulo the bearings wearing out -- and good bearings should last a long time.



Heat also kills alternators. If they get too hot the bearings can fail, the stator windings can burn up, and the diodes can fail. Remember that, if you are trying to draw full output from your alternator, it is self protected by the resistance of the windings. That protection comes at the expense of the stator windings getting hot -- REALLY hot. They need a lot of air to get rid of that extra heat. That is why most alternators have those little fans on the front -- to force air through the alternator to cool the stator windings. If you keep your alternator cool none of the bad things are likely to happen. Simple.



As long as we are thinking of alternator failures it is time to talk about how an alternator can produce an overvoltage condition. This is not really an alternator failure, per se. It happens when the regulator "runs away" and turns the field on full. At that point the alternator produces full output. At first the battery accepts the excess but that doesn't last. The voltage rises and battery boils and/or explodes. Without the battery to absorb the excess, buss voltage goes to the moon. Did you know that an alternator with the field turned full on can hit over 100V? Kiss your avionics good-bye. To save everything most aircraft have an OV relay that disconnects the regulator from the field of the alternator. This shuts down the alternator. Most OV relays open at around 16V/32V depending on whether the electrical system is 14V or 28V.



Oh, and some alternators have internal regulators. The regulator is inside the case. The only lead needed is the B-lead. Most of these are "self exciting" which means that the residual magnetism in the armature is enough to generate enough output to turn the voltage regulator on and start the alternator working. All you have to do is spin them fast enough to start up. Once that happens, you can slow them to idle and they will work just fine. The only way you can turn them off is to stop turning the armature. Virtually all automotive alternators are of this type these days.



Of course, this leads to a very interesting failure mode. If the VR fails in such a way that it turns the field on hard, the alternator will "run away" and produce a serious OV condition. Since there is no way to control the field circuit with this type of alternator there is no way to add an OV protection relay short of modifying the alternator. This type of alternator is therefore a time-bomb. The fact that so few actually fail mens that you will likely never see this failure should you equip your Yak or CJ with a modified truck alternator with an internal regulator. But if it DOES fail, kiss your electrical accessories and your avionics good-bye.



One last thing on this: some of these internally-regulated alternators have a terminal that can be used to turn the alternator on or off. Some think that this will save their bacon in the case of an OV event, i.e. if you detect an OV event just manually turn off the alternator. The only problem is, this on/off lead depends on the VR working properly. If the VR's field-controlling device (a transistor inside the VR) fails shorted, the field is turned on and the on/off switch will have no effect. 



The only way to make an internally-regulated alternator completely safe is to remove the diode-trio (a separate set of diodes used to power the regulator from the stator independent of the B-lead) and feed power to the regulator from a separate wire to the buss that is under your control. You can even use the on/off control terminal to do this. Of course, this implies modifying your alternator in the first place. Why not just start with an externally-regulated alternator and do it right.



Permanent Magnet (PM) Alternators (Dynamos):



I know that some of you are using dynamos (PM alternators) in your aircraft. The ones I am most familiar with are the units from B&C that mount on a vacuum pump pad and produce 5A-10A max. These are great for day VFR aircraft as the power requirements are very low, usually a couple of instruments, a comm, an intercomm, and a GPS receiver.



The dynamo is always running at full output for its RPM since its magnetic field is always full on. There is no control as with a field winding where you can vary a current to vary the magnetic field. This means that you need to provide brute-force regulation of the output of the dynamo and that is what its VR does. Essentially it just burns up the excess output as heat. Since the currents are relatively low, this turns out not to be a big problem. This is just about the simplest and most reliable electrical generating device you can have. If I had a day VFR airplane that didn't need much electrical power, this the way I would go.



Generators:



Generators add a LOT of monkey-motion to the power generating equation. Before I get into the details let's go back about 200 years to Michael Faraday playing with wire and magnets. He determined that he could generate an electric current by either moving a wire within a magnetic field or by moving a magnet past a stationary wire. The only problem was (and is), when you move the wire or magnet one way the current flows in one direction and then when you bring the magnet or wire back to its starting point, the current moves in the other direction. The only problem is, we want the current to always move in one direction. Therefore, we need a way to reverse the wiring every time the current reverses. 



Since the 1950s we have had these nice silicon diodes that can do that job for us. They are small, use very little power, and (almost) never wear out. They made the alternator possible. But before then we had to do things the brute-force way. We needed a physical switch to reverse the connection at the right time to keep the current flowing in only one direction. In a generator, this switch is called the commutator and lives at the end of the armature. More on this in a second.



There is one big difference in the architecture of a generator and an alternator. In the alternator the exciting magnetic field spins (either a PM or a field winding) and the power-producing windings are on the outside. In a generator the field windings (or PM) are on the outside and the power-producing windings are on the spinning armature. In the alternator the slip rings only have to handle the current of the field, a few amps at most. Also, the slip rings don't have to switch on and off. They are going to live a long time. In a generator the commutator has to switch the full power output of the power-generating windings of the armature. Every time this happens there is a small spark which vaporizes a tiny bit of the commutator and its brushes. Eventually the commutator and its brushes disappear. So the commutator is the first achilles-heel of the generator. Because of the commutator, your generator has a limited life. You can make it as long as possible by making the contact area of the commutator and its brushes as large as possible but you can never eliminate the problem entirely. Now on to more of the required extra complexity. 



Remember that the diodes in the alternator prevented the battery from forcing power back through the alternator so we could leave the alternator always connected to the battery? (They do that in cars.) Well, you can't do that with a generator. If the generator is not producing output and it is connected to the battery, current from the battery will flow through the alternator turning it into an electric motor. Needless to say the battery won't last long in that case. So the generator controller has to have a low-output cut-off switch that disconnects the output of the generator when its output is too low. That is why generators drop off-line at low RPM. Oh, and that switch is a possible point of failure, much more likely to fail and wear out that the diodes in an alternator.



On the other end of the spectrum the commutator and its brushes can only handle so much current. Unlike the self-protecting stator windings in the alternator, if you try to get too much current out the commutator and the brushes they will destroy themselves. So the generator controller has a current-limiting switch (relay) that disconnects the generator's output if the current gets too high. This is another point of failure for our generator system. (Actually there are some really clever generator voltage regulators that can recognize the over-current state and actually reduce field current to accomplish the same thing but they are not very common.)



Lastly, the make/break arcing of the commutator, the make/break arcing of the field control relay (vibrator), and the make/break arcing of the over-current relay all make electrical noise that could get into your avionics. This requires one more thing that an alternator system doesn't have: a filter at the output of the generator. This is a big, clunky box full of coils and capacitors designed to get rid of that noise so only "clean" DC gets to the system buss. It takes up space and it weighs something, about 8 lbs if I recall, so it uses up useful load.



So, as you can see, the generator is a LOT more complex than an alternator. It has MANY more things that can and do break. It has a lot more adjustments to keep it working properly. All that extra stuff weighs more. This is why I won't put a generator back into a system I already have apart. 



So getting back to what I said at the beginning, if you already have a generator, use it until it breaks. After all, it IS working. (If it ain't broke, don't fix it.) But once it craps out and you find yourself in the unenviable position of trying to figure out and then fix what is wrong, it may be easier to just rip it out and start over with an alternator. The alternator is much simpler, will last longer, and be less trouble. Personally, I prefer flying my airplane to troubleshooting. I already have a reciprocating engine and a pneumatic system to capture and hold my attention. I don't need any extra distractions.

 --

Brian Lloyd                         3191 Western Drivebrian HYPHEN 1927 AT lloyd DOT com    Cameron Park, CA 95682

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

— Antoine de Saint-Exupéry



PGP key ID:          12095C52A32A1B6C

PGP key fingerprint: 3B1D BA11 4913 3254 B6E0  CC09 1209 5C52 A32A 1B6C



 



 [quote][b]

mark.bitterlich(at)navy.m
Guest

Posted: Mon Feb 18, 2008 12:21 pm Post subject: Alternator vs Generator and Overvoltage

I just wrote something on this Craig.... Our minds must have been in

sync. 



Stock YAK's most certainly do contain over-voltage protection.  



Mark Bitterlich

 



--

mark.bitterlich(at)navy.m
Guest

Posted: Mon Feb 18, 2008 1:13 pm Post subject: Alternator vs Generator and Overvoltage

Brian knows I have to respond to this. 



I agree with everything he has said.  Great explanations as well for the theory between the two devices.  Further, if you have some money hanging around in your pocket that you need to get rid of, don't wait for the generator to fail... Replace it right now.  Figure around $1000 for on over the counter model, and some hours for you're A&P to wire it in.  



The Alternator system is very reliable.  I don't follow their failure rates at all, and I only know of one that failed (the bigger B&C model with external regulator with field winding).  The owner sent it back for repair, and B&C sent him a replacement.  $700 for the replacement.  



As Brian said, the generator system is much more complicated, and it has come to my attention that very few people really understand it.  Even if you have Brian's understanding of the theory of operation, you still have to cross-match every piece you know HAS to be there by theory, to where the Russians actually decided to put the thing, and what they decided to make it look like, and worse yet, how they labeled it.  This makes troubleshooting a Russian electrical generation system one huge pain in the ass.  



On the flip side... It is CHEAPER to maintain if you: 



1.  Learn how it works. 

2.  Buy some spare parts to keep handy.  



Figure a spare generator... $100.  

Spare over-voltage module, regulator, etc.  Also around $50 to $100 for each.  

The "Combination" relay is a SOB to get ahold of, so all bets are off there, but it can be repaired. 



That said, I have over 700 hours on my YAK-50 here are a list of my electrical "issues".



Main fuse in forward electrical box failed internally.  This is a pretty common event and has happened to about 5 aircraft that I am aware of.  You need to know where this puppy is and how to replace it.  It has nothing to do with generators or alternators!  



Sheared generator shaft coupling (reason unknown, but would have just as easily happened with an Alternator in my humble opinion).  I replaced the whole generator.  Cost... Zero, a guy with an old ugly one laying in the corner gave it to me.  I put it on, it has worked perfectly every since.  



Failed Combination Device.  This contains the main contactor relay.  I fixed it by replacing the defective internal Russian relays with American made ones.  Took a week to figure out the electrical circuit involved.  Another few hours to try and explain it with an article posted here (a fair but not GOOD job), and then about 3 hours to actually repair it.  Cost, $10 for the relays.  



One friend of mine was sure he has a bad generator system.  All he had was bad batteries.  



So thus my conclusion.  Original system.  Cheap to repair.  Complicated to understand.  



Alternator System.  Easy to fix, easy to understand, not cheap for the average guy.  



Mark Bitterlich



P.s.  Another little tidbit between Alternators and Generators.  



1.  If your batteries ever go totally dead in the air or on the ground... I mean zero or really LOW battery voltage.... And the alternator is not already on-line... It will never turn on.  It needs a little juice to get it going so to speak. For example, you're flying along and think you may have a battery problem, so you turn off your alternator to check the battery.  If the battery has indeed failed and gone to zero... Turning your alternator back on will NOT restore power.  Basically you're screwed.  Something to keep in mind before turning off the alternator!      



2.  Do the same thing with a generator and it will come back on line and operate and power your aircraft.  



A small thing, but part of the overall picture.    



 



 



--

Gill.G(at)gpimail.com
Guest

Posted: Mon Feb 18, 2008 2:29 pm Post subject: Alternator vs Generator and Overvoltage

I believe the Yak generator is like the CJ generator is type 'B' and it is

powered like an alternator.  That is power is supplied by the battery to the

fields.  So I would be careful about checking poor battery condition in

flight.



Gill 



--

yakplt(at)yahoo.com
Guest

Posted: Mon Feb 18, 2008 3:11 pm Post subject: Alternator vs Generator and Overvoltage

That is incorrect Gill.  With no battery installed in the aircraft at all, the generator will come on line at 20 volts.  With a battery installed, it will connect to the aircraft mains within a few volts of the battery.  The generator voltage regulation system is completely self contained.  If you want an explanation of how the whole system works, please read the article I wrote on the YAK system. 

  

 Mark Bitterlich

 ---

brian-1927(at)lloyd.com
Guest

Posted: Mon Feb 18, 2008 7:06 pm Post subject: Alternator vs Generator and Overvoltage

 	  Quote: 	
		   P.s.  Another little tidbit between Alternators and Generators.



 1.  If your batteries ever go totally dead in the air or on the  

 ground... I mean zero or really LOW battery voltage.... And the  

 alternator is not already on-line... It will never turn on.


	


Not entirely true. Self-exciting alternators will. Even a regular  

alternator will come on line if you can get all the loads off the bus  

first.



 	  Quote: 	
		   It needs a little juice to get it going so to speak.


	


That is true. OTOH the reason that the generator comes on-line without  

the battery is the residual magnetism in the field. The alternator has  

the same thing. You can see this by disconnecting the 'B' lead,  

putting a voltmeter on it, and spinning up the alternator. You will  

get some output. It should be enough to excite the field to bootstrap  

the alternator to full output as long as nothing else is using that  

output. As I said, that is how a self-exciting alternator gets going.  

And most internally-regulated alternators are self exciting.



But there is another issue. Neither a generator system nor an  

alternator system should be operated without a battery in the circuit.  

The battery is needed to stabilize the voltage. Without it you have  

nothing to absorb the excess output when you load-dump. Neither an  

alternator nor a generator can change its output suddenly. It takes  

time for the magnetism in the field to ramp up or ramp down with a  

field current change. (Current lags voltage in an inductor if you want  

to get technical.) That means that, without a battery, turn off the  

landing light and watch the alternator or generator create an  

overvoltage event.



Now we have said WAY more about alternators and generators than anyone  

else wanted to hear. 



--

Brian Lloyd                         3191 Western Drive

brian HYPHEN 1927 AT lloyd DOT com    Cameron Park, CA 95682

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

— Antoine de Saint-Exupéry



PGP key ID:          12095C52A32A1B6C

PGP key fingerprint: 3B1D BA11 4913 3254 B6E0  CC09 1209 5C52 A32A 1B6C

ChangDriver

Joined: 15 Sep 2007
Posts: 266

Posted: Tue Feb 19, 2008 12:51 pm Post subject: Re: Alternator vs Generator and Overvoltage

Brian and Mark:



Thanks so much for sharing your technical expertise.  Now, I gotta go find the overvoltage regulator for my CJ!!



It also seems as though (if the splines are the same on Housai and M-14) that if B&C had put a seal on the shaft, it would have worked on both engines!!



Thanks again,



Craig



PS - Brian, that was not more than I wanted to hear on the subject, it was excellent!!

brian-1927(at)lloyd.com
Guest

Posted: Tue Feb 19, 2008 5:01 pm Post subject: Alternator vs Generator and Overvoltage

On Feb 19, 2008, at 12:51 PM, Craig Winkelmann, CFI wrote:



 	  Quote: 	
		   

 >



 Brian and Mark:



 Thanks so much for sharing your technical expertise.  Now, I gotta  

 go find the overvoltage regulator for my CJ!!


	


There isn't one. The Yak has an OV relay. The CJ doesn't. That is why  

I did the project to make an OV module for the CJ.



 	  Quote: 	
		   It also seems as though (if the splines are the same on Housai and  

 M-14) that if B&C had put a seal on the shaft, it would have worked  

 on both engines!!


	


If you make a plate with a seal it will. There are people flying CJ's  

with B&C alternators with an adaptor plate.



 	  Quote: 	
		  



 Thanks again,



 Craig



 PS - Brian, that was not more than I wanted to hear on the subject,  

 it was excellent!!


	


You are most welcome.

Brian Lloyd                         3191 Western Drive

brianl AT lloyd DOT com             Cameron Park, CA 95682

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



PGP key ID:          12095C52A32A1B6C

PGP key fingerprint: 3B1D BA11 4913 3254 B6E0  CC09 1209 5C52 A32A 1B6C

ChangDriver

Joined: 15 Sep 2007
Posts: 266

Posted: Wed Feb 20, 2008 7:04 am Post subject: Re: Alternator vs Generator and Overvoltage

Brian:



Instead of saying:



Thanks so much for sharing your technical expertise. Now, I gotta 

go find the overvoltage regulator for my CJ!! 



I should have said:



Now I'll go call Bob at aereoelectric.com and find out more about the overvoltage device you designed.  



Craig



By the way, there is a unit made by Zeftronics that may work.  Don't know how much it is.  But it was designed for 50 Amp Delco Remy generator.  Has 3 amp max field current, regulates 28.4 v +/- 0.4 and does overvoltage protection at 32 volts +/- 0.8 volts.  Provides reverse current protection, current limiter, overvoltate protection, under and overvoltage sensing, and has electronic controlled generator build-up circuitry.  Unit is part number G2XXPN and can be found at zeftronics.com.  Sounds expensive!!

brian-1927(at)lloyd.com
Guest

Posted: Wed Feb 20, 2008 8:23 am Post subject: Alternator vs Generator and Overvoltage

 	  Quote: 	
		   By the way, there is a unit made by Zeftronics that may work.  Don't  

 know how much it is.  But it was designed for 50 Amp Delco Remy  

 generator.  Has 3 amp max field current, regulates 28.4 v +/- 0.4  

 and does overvoltage protection at 32 volts +/- 0.8 volts.  Provides  

 reverse current protection, current limiter, overvoltate protection,  

 under and overvoltage sensing, and has electronic controlled  

 generator build-up circuitry.  Unit is part number G2XXPN and can be  

 found at zeftronics.com.  Sounds expensive!!


	


It is and I am not sure you can still get them. Regardless, it is a  

complete generator control system. You could use it to replace the VR  

in the CJ and get all the benefits. OTOH, if you have gone that far  

you may want to just switch to an alternator and get rid so some of  

the weight and wiring.



Brian Lloyd

Granite Bay Montessori School          9330 Sierra College Bl

brian AT gbmontessori DOT com          Roseville, CA 95661

+1.916.367.2131 (voice)                +1.791.912.8170 (fax)



PGP key ID:          12095C52A32A1B6C

PGP key fingerprint: 3B1D BA11 4913 3254 B6E0  CC09 1209 5C52 A32A 1B6C

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