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Over voltage required for EarthX battery

Also have a AFS 4500 so I assume it will yell at me if voltage exceeds XX?

I have an AFS 4500 and it has an alarm/alert for low voltage. It worked on one occasion when I left my Alt field switch off and flew for about 15 mins in that condition.

It also has a high voltage alarm but I've never heard it alert.
 
We bought an Earth-X battery frok Wicks at Oshkosh 2017. Ended up triggering a BMS Earth-X warning on the G3X GEA 28 interface LRU. Called Kathy af Earth-X and couldn't be more impressed. First off a real human in charge answered the phone and determined that based on our serial number the battery we bought was very old without the latest battery monitoring software with the sensitivities updated for G3X compatibility. So Kathy took the time to make the problem her own (as is appropriate) and didn't hesitate to send out a brand new unit at no cost for exchange. She was super cool and totally involved. A very human experience. A breath of fresh air that harkens back to a time when a manufacturers stood behind their products and focused on customers. Not even a whiff of back room bean counters screwing the whole thing up. You are talking to a person where the buck stops. No blow offs. No excuses. Just factual interaction with a new friend. This is almost too good to be true. I dearly hope that Earth-X can expand upon the volume of happy customers without becoming just another modern company.

Meanwhile the new replacement was exactly as promised. Works great without B. Betty complaining about it.

Jim
 
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Now if I understand what I've read so far, the field wire that I have after a breaker and toggle switch is only a signal? That the field actual draws necessary current from the B lead? So disconnection of the field wire will not stop a runaway alternator? Again, in this case, a Denso, same as Vans. Enlighten me, please.

The field wire is a power supply. The issue is how the internal voltage regulator is designed.

Traditional auto alternators of this type draw power via the field wire for initial excitement during startup, then switch to self-excitement at operating RPM. That's not exactly the same thing as "draws from the B-lead", but conceptually close enough...after start, the field gets its power internally, via the regulator.

The preferred alternator for our application always draws all its field power via the field wire/switch/breaker. An overvoltage device installed in that field line will sense voltage rising above the desired level, and disconnect the field power almost instantly by shorting the field line to ground and popping the breaker.

A Plane Power has the OV device built into the internal regulator, same function.

Assuming you do not have a Plane Power, here is the easy test to determine what you do have. Turn on the master. Note buss voltage, which is battery voltage alone. Now fire up the engine. With the alternator switch and breaker closed, buss voltage will rise to some higher figure, typically 13.8 to 14.5V. Now, with the engine running, open the field switch or pull the breaker. If buss voltage does not drop back to battery voltage, you must wire a disconnect contactor in the B-lead. If buss voltage does drop back to battery voltage, wire an OV device into the field lead.
 
The field wire is a power supply. The issue is how the internal voltage regulator is designed.

Traditional auto alternators of this type draw power via the field wire for initial excitement during startup, then switch to self-excitement at operating RPM. That's not exactly the same thing as "draws from the B-lead", but conceptually close enough...after start, the field gets its power internally, via the regulator.

The preferred alternator for our application always draws all its field power via the field wire/switch/breaker. An overvoltage device installed in that field line will sense voltage rising above the desired level, and disconnect the field power almost instantly by shorting the field line to ground and popping the breaker.

A Plane Power has the OV device built into the internal regulator, same function.

Assuming you do not have a Plane Power, here is the easy test to determine what you do have. Turn on the master. Note buss voltage, which is battery voltage alone. Now fire up the engine. With the alternator switch and breaker closed, buss voltage will rise to some higher figure, typically 13.8 to 14.5V. Now, with the engine running, open the field switch or pull the breaker. If buss voltage does not drop back to battery voltage, you must wire a disconnect contactor in the B-lead. If buss voltage does drop back to battery voltage, wire an OV device into the field lead.

Thank you, Dan. Now I get it.
Do you suppose with the EFIS screaming "Check voltage" the meat servo could react fast enough to keep from frying the EarthX?
 
Good summary, but...

The field wire is a power supply. The issue is how the internal voltage regulator is designed.

Traditional auto alternators of this type draw power via the field wire for initial excitement during startup, then switch to self-excitement at operating RPM. That's not exactly the same thing as "draws from the B-lead", but conceptually close enough...after start, the field gets its power internally, via the regulator.

The preferred alternator for our application always draws all its field power via the field wire/switch/breaker. An overvoltage device installed in that field line will sense voltage rising above the desired level, and disconnect the field power almost instantly by shorting the field line to ground and popping the breaker.

A Plane Power has the OV device built into the internal regulator, same function.

Assuming you do not have a Plane Power, here is the easy test to determine what you do have. Turn on the master. Note buss voltage, which is battery voltage alone. Now fire up the engine. With the alternator switch and breaker closed, buss voltage will rise to some higher figure, typically 13.8 to 14.5V. Now, with the engine running, open the field switch or pull the breaker. If buss voltage does not drop back to battery voltage, you must wire a disconnect contactor in the B-lead. If buss voltage does drop back to battery voltage, wire an OV device into the field lead.

Keep in mind there's been some speculation that a regulator _could_ fail in some way that changes this behavior - a unit that formerly powered down with removal of external field current when tested _might_ become non-controllable in the event something fries internally. (Can't prove a negative and there's no way to know for sure.) For this reason, even though my IR Denso alternator does power down when I open the field switch, my crowbar circuit from now on both trips the field breaker and opens a B-lead contactor. Belt and suspenders.
 
blain,
i am counting on a pilot's reaction to be ample to disconnect the charging source from a battery before the battery goes over the edge.my system is designed for 2 earth x batteries.i think i have plenty of time after a flashing light to turn off the field and pull [push pull type] the breaker that disconnects the alternator's charge from the battery.the instant response used to be required [so the old beliefs go] that the avionics would/could be fried by anything slower than a crowbar device.
 
Thank you, Dan. Now I get it.
Do you suppose with the EFIS screaming "Check voltage" the meat servo could react fast enough to keep from frying the EarthX?

Can't speak for the EarthX, but you might fry some avionics.

Given the low cost and simplicity of OV devices, going without is like trusting a fart.
 
Keep in mind there's been some speculation that a regulator _could_ fail in some way that changes this behavior - a unit that formerly powered down with removal of external field current when tested _might_ become non-controllable in the event something fries internally. (Can't prove a negative and there's no way to know for sure.) For this reason, even though my IR Denso alternator does power down when I open the field switch, my crowbar circuit from now on both trips the field breaker and opens a B-lead contactor. Belt and suspenders.

Hi Bill; hope you don't mind me quoting you to expand on that.

I hope this pic link works; I tried to copy it from a post by Ross F in another thread.
http://www.vansairforce.com/community/showpost.php?p=1215946&postcount=55

The line labeled 'S' is the control line to the regulator (what almost everyone here is calling the 'field terminal').

Look down & right, at the coil symbol at the bottom of the image (below the star-shaped 3-coil system). This is the field winding in the alternator. Note that the wire from the left end of the coil is tied directly to 3 diodes, fed by that 3-coil network. This is DC going to the B-lead (output) of the alternator. Note also that this B-lead voltage is fed directly into the 'IC regulator'.

Now follow the wire from the other end of the coil, into the blank box labeled 'IC regulator'. In order for the field winding to generate a magnetic field (which, along with rotation, is what makes the alternator make power), that DC path must be completed to ground. It's not shown in the drawing, but inside that blank box there's a transistor that is a 'gate keeper', and controls the current flowing through the field winding and out of the blank box, on the wire just below the coil, to the ground symbol in the drawing.

Here's the point of all this:

If that (undrawn) 'gate keeper' transistor shorts out, ask yourself what happens to the field current. Then ask yourself how you shut down the alternator, with that transistor shorted.

Now, there may be some internally regulated alternators on the market that aren't wired this way. But I hope it's obvious that with this particular design, if the regulator fails, there is no certainty that it can be shut down by removing power from the 'field' terminal. It should also be obvious that being able to shut it down using the 'field' terminal *while it's working properly* is no guarantee that you'll be able to do it after a regulator failure (which is what causes an overvoltage event).
 
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Hi Bill; hope you don't mind me quoting you to expand on that.

I hope this pic link works; I tried to copy it from a post by Ross F in another thread.
http://www.vansairforce.com/community/showpost.php?p=1215946&postcount=55

The line labeled 'S' is the control line to the regulator (what almost everyone here is calling the 'field terminal').

Look down & right, at the coil symbol at the bottom of the image (below the star-shaped 3-coil system). This is the field winding in the alternator. Note that the wire from the left end of the coil is tied directly to 3 diodes, fed by that 3-coil network. This is DC going to the B-lead (output) of the alternator. Note also that this B-lead voltage is fed directly into the 'IC regulator'.

Now follow the wire from the other end of the coil, into the blank box labeled 'IC regulator'. In order for the field winding to generate a magnetic field (which, along with rotation, is what makes the alternator make power), that DC path must be completed to ground. It's not shown in the drawing, but inside that blank box there's a transistor that is a 'gate keeper', and controls the current flowing through the field winding and out of the blank box, on the wire just below the coil, to the ground symbol in the drawing.

Here's the point of all this:

If that (undrawn) 'gate keeper' transistor shorts out, ask yourself what happens to the field current. Then ask yourself how you shut down the alternator, with that transistor shorted.

Now, there may be some internally regulated alternators on the market that aren't wired this way. But I hope it's obvious that with this particular design, if the regulator fails, there is no certainty that it can be shut down by removing power from the 'field' terminal. It should also be obvious that being able to shut it down using the 'field' terminal *while it's working properly* is no guarantee that you'll be able to do it after a regulator failure (which is what causes an overvoltage event).

The S wire is actually the sense wire directly to the regulator from the battery, there is no switch in that line. Since it's wired hot in the car, it's not designed to control the field, it only provides battery reference voltage to the regulator. My field switch is not connected here, it's connected to the IG terminal.
 
I stand corrected; it should the the IG terminal that controls. But the question remains. Given the drawing, once the alternator 'starts', if the semiconductor that directly controls the ground path of the field winding fails shorted, how can the alternator be shut down?
 
I stand corrected; it should the the IG terminal that controls. But the question remains. Given the drawing, once the alternator 'starts', if the semiconductor that directly controls the ground path of the field winding fails shorted, how can the alternator be shut down?

Maybe you're seeing something different here in this schematic that I'm missing.

We can either kill power or kill ground to the field windings. Since cutting power to the IG terminal kills the output normally, I don't see why a shorted transistor on the field ground leg would make any difference to that. You'd just be at maximum output. In fact, with a properly sized field breaker, you should be able to have it pop from excess field current if the field control transistor ever completely shorted, which should shut it all down automatically.

I must admit, I've never tried shutting off field current at high rpms to see if that might make a difference. I will give that a shot next time I fly.
 
I hope this pic link works; I tried to copy it from a post by Ross F in another thread.
http://www.vansairforce.com/community/showpost.php?p=1215946&postcount=55

The line labeled 'S' is the control line to the regulator (what almost everyone here is calling the 'field terminal').

I can't speak for everyone, but no, "S" and "B" are both buss voltage, while "IG" (Terminal 3) is best described as a field lead. With the ignition on, prior to start, it supplies battery voltage to the rotor field. After start, output voltage rises, the system is self-exciting, and current no longer flows in through Terminal 3....the "traditional alternator" I described to Blain.

Observations.

Although it may stand for something else, I've always thought of "S" as the "sense" terminal, i.e. how the regulator knows buss voltage. Terminals S and B can be connected together (how it was wired in the Toyota), or S can be connected to the buss bar, or to Terminal 3. I have no idea what happens if S is disconnected from a power source.

As drawn, I agree it can run away if the regulator shorts to ground. However, it may be possible to modify it for aircraft use with OV protection.

Opening the three feed diodes (here pointing left) disconnects the field from the windings, making Terminal 3 the only field power source. So, jumper S to B, leave L unused, clip the diodes, and install an OV device on the buss feed to Terminal 3.
 
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Maybe you're seeing something different here in this schematic that I'm missing.

We can either kill power or kill ground to the field windings. Since cutting power to the IG terminal kills the output normally, I don't see why a shorted transistor on the field ground leg would make any difference to that. You'd just be at maximum output. In fact, with a properly sized field breaker, you should be able to have it pop from excess field current if the field control transistor ever completely shorted, which should shut it all down automatically.

I must admit, I've never tried shutting off field current at high rpms to see if that might make a difference. I will give that a shot next time I fly.

The problem occurs because the field control transistor is connected internally to a diode trio fed by the stator. Once the alternator is generating power, the IG signal will not turn off the alternator if the transistor is shorted; the alternator will just keep generating power. An externally regulated alternator is not like this, but is controlled by the field terminal. So, to reliably stop a runaway alternator with an internal regulator, an external relay needs to be in series between the alternator B lead and the loads, with an electronic device such as a crowbar controlling the relay and field breaker to shut it down.
 
That answers my question. I have to chop the ?B? lead in a runaway condition on an internally regulated alternator unless it?s a Plane Power. So add another contactor, crowbar and associated wiring or install a new alternator?

I really appreciate the benefits of the EarthX but Im not sure at this point the extra complexity and expense are worth it.
 
That answers my question. I have to chop the ?B? lead in a runaway condition on an internally regulated alternator unless it?s a Plane Power. So add another contactor, crowbar and associated wiring or install a new alternator?

I really appreciate the benefits of the EarthX but Im not sure at this point the extra complexity and expense are worth it.

The alternator issue really isn't about EarthX. It's about protecting your avionics, and in-flight implications of losing avionics.
 
ACS Plane Power 60 amp alt kit is $450??

So have we decided if the Meat servo can respond quick enough to save the avionics by opening the master, will the EarthX just smoke or will it still pose some other hazard out on the firewall?

I?m willing to accept the risk of losing the avionics as long as the battery doesn?t pose a fire Hazzard. Battery is on the right, fresh air NACA on the left. Seems like other then an inconvenience it wouldn?t be a disaster.

BTW, the EarthX spins my 360 so fast I have to hold the brakes :p
 
Your call, but I'd never depend on myself to respond quickly enough if the reg fails during high workload in the cockpit. Especially since automatic OV protection using a B-lead contactor can be done for <$100 & <1 pound, & avionics would be in the $thousands.
 
A summary of sorts.

Good discussion. 3 things are basic as I have researched and learned.

1. even a single high voltage spike can damage the electronics, an OV protection device is quick and solves that.

2. While a stream of spikes can injure and incite the EarthX battery, it is primarily not a single spike issue, it one of accumulative internal heating over time. That takes seconds, maybe minutes. So protecting the battery is two fold, a clean, lowish AC content, and nominal voltage not out of range. The latter could be an output relay opening, it is plenty fast to protect the battery (just not electronics)

3. In my study of internal regulators, found that some have the internal sense connected and some don't even if there is an external activation wire. The one that does not have an internal sense connection could certainly shut down with OVP in the circuit. The point is that even with an external activation, they are not all the same internally. This may be the source of some apparent conflict here regarding the IR versions.

Ross's experience with the ND versions he is familiar with seem to have no internal connection to output.

Sorry, on #3, I don't have a reference as my access to the companies (Lester) information has expired. Maybe some one in the OEM world can get more definitive information from an alternator manufacturer.
 

Very general, and doesn't address the stator feed to the rotor field.

People are saying here that power is being fed from the stator to the field windings when the alternator is running, I am not clear then why shutting off power to terminal 3 (IG) shuts off the alternator.

In the Toyota alternator diagram you posted in the other thread, the stator unquestionably feeds the rotor field. Take another look.

You say the alternator you have in hand does shut down when when power is removed from IG. That observation does not match the diagram. I suspect the observation.

Note this line from a previous post:

I must admit, I've never tried shutting off field current at high rpms to see if that might make a difference. I will give that a shot next time I fly.

Remember, power to IG typically starts the alternating process. Without external field power, the rotor (an electromagnet) would initially have nothing but residual magnetism to induce current flow in the stator windings.

After the rotor is spinning, that initial shot of external field power is no longer needed. The field is powered via the stator diodes.

So, if your test was to disconnect IG power prior to engine start, yep, it won't have a B output. Try shutting off IG power after it's spinning, and report.
 
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I?m willing to accept the risk of losing the avionics as long as the battery doesn?t pose a fire Hazzard.

You must have missed the memo. It does not pose a fire hazard. It poses a huge smoke hazard.

Quit fooling around. You want to use an EarthX, then install OV protection as EarthX specifies. The entire community will appreciate your cooperation.
 
Good discussion. 3 things are basic as I have researched and learned.

1. even a single high voltage spike can damage the electronics, an OV protection device is quick and solves that.

2. While a stream of spikes can injure and incite the EarthX battery, it is primarily not a single spike issue, it one of accumulative internal heating over time. That takes seconds, maybe minutes. So protecting the battery is two fold, a clean, lowish AC content, and nominal voltage not out of range. The latter could be an output relay opening, it is plenty fast to protect the battery (just not electronics)

3. In my study of internal regulators, found that some have the internal sense connected and some don't even if there is an external activation wire. The one that does not have an internal sense connection could certainly shut down with OVP in the circuit. The point is that even with an external activation, they are not all the same internally. This may be the source of some apparent conflict here regarding the IR versions.

Ross's experience with the ND versions he is familiar with seem to have no internal connection to output.

Sorry, on #3, I don't have a reference as my access to the companies (Lester) information has expired. Maybe some one in the OEM world can get more definitive information from an alternator manufacturer.

EDIT: Bill & I have been having an off-line discussion about item 3. My response below was a reaction to the term 'sense line', which electron pushers (at least this one) assume means a separate input to the regulator that's used to remotely sense voltage at the load, so the regulator can supply more accurate voltage at the load. Apparently, Bill's referring to the terminal that actually powers the regulator. In that case, if power comes from outside the alternator (AND the field winding gets its power from the regulator; not directly from alternator output), then I'd agree with Bill.

Bill, sorry for the confusion.


#3: the positive control issue is completely unrelated to the sense terminal. Apologies for inadvertently even mentioning that terminal. Follow the current path for the field winding in the drawing. The field winding is directly connected to the 3 left-pointing diodes. Once the alt is running, those diodes are supplying DC current to the field winding. The current path to ground is completed (and varied, to control B-lead output *voltage*) by semiconductors inside the 'IC regulator' block. If any of those semiconductors inside that block fail in a fashion that results in an 'on' condition, supplying a current path to ground, then the field will be fully on, which means there is no control over the alternator's output. The location of voltage sensing is irrelevant, because there's no longer any control.
 
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You must have missed the memo. It does not pose a fire hazard. It poses a huge smoke hazard.

Quit fooling around. You want to use an EarthX, then install OV protection as EarthX specifies. The entire community will appreciate your cooperation.

Ouch. Didn?t realized I was being uncooperative.
 
The alternator issue really isn't about EarthX. It's about protecting your avionics, and in-flight implications of losing avionics.

Exactly. This level of control of an IR alternator is required no matter the type or brand of battery, to prevent a very bad day in the air for you and your avionics and battery.
 
After the rotor is spinning, that initial shot of external field power is no longer needed. The field is powered via the stator diodes.

So, if your test was to disconnect IG power prior to engine start, yep, it won't have a B output. Try shutting off IG power after it's spinning, and report.

I do this after every flight, prior to engine shutdown, hundreds of times over the last 14 years. The low voltage buzzer and light come on within about 10 seconds (12.5 V threshold). I'll shoot a video next time...
 
Ross, have you verified that the schematic you posted is how *your* alternator is actually wired? Car parts makers aren't bound by type certificates; stuff often changes multiple times, even in the same model year. They're also notorious for publishing 'schematics' that are only vague representations of how something is actually wired.
 
IG can power it off

...

Remember, power to IG typically starts the alternating process. Without external field power, the rotor (an electromagnet) would initially have nothing but residual magnetism to induce current flow in the stator windings.

After the rotor is spinning, that initial shot of external field power is no longer needed. The field is powered via the stator diodes.

So, if your test was to disconnect IG power prior to engine start, yep, it won't have a B output. Try shutting off IG power after it's spinning, and report.
I did this on one alternator a long time ago, and could get it to shut down when I removed 12v from the IG. No idea if this would still work on an alternator with a failed VR, tho, and of course this is only one data point. I would not generalize to any other alternators. My assumption is that during a failure, you will not have any control over the alternator, and you need to put in some way to disconnect it from stuff you don't want damaged.

http://www.rv8.ch/eggenfellner-subaru-ultra-mini-alternator-2026/
 
Ross, have you verified that the schematic you posted is how *your* alternator is actually wired? Car parts makers aren't bound by type certificates; stuff often changes multiple times, even in the same model year. They're also notorious for publishing 'schematics' that are only vague representations of how something is actually wired.

Pretty darn sure as I've wired many of these up the same way on race cars and airplanes but I'll check my plane this weekend and try to shoot the video if it's warm outside.

This is where my confusion came from after so many people telling me opening the IG switch would not shut off a spinning AE86 ND IR alternator.
 
Not *your* wiring; the guts of the alternator/regulator.

Not sure what you're saying here. I've used a couple of Toyota manuals over the years OEM, Haynes etc. and all depict the same thing as do several other aftermarket sources on the web I checked recently. If I do indeed have my "field" switch wired to what is the referred to as the IG terminal in all these sources and that shuts down the alternator, will you folks believe me or am I wasting my time and breath here?

Until someone cuts one open, none of us here really know 100% for sure what the internal arrangement is on the ND alternator in question but suggesting the manuals are not a true representation doesn't go too far past whimsical conjecture for me. If someone has some better facts than what we have a this time, present them.
 
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following

Ross, I really want to know. I have been following this thread closely awaiting your response. Thank you for the time you are putting in to educate us newbies.
 
Not sure what you're saying here. I've used a couple of Toyota manuals over the years OEM, Haynes etc. and all depict the same thing as do several other aftermarket sources on the web I checked recently. If I do indeed have my field switch wired to what is the referred to as the IG terminal in all these sources and that shuts down the alternator will you folks believe me or am I wasting my time and breath here?

I'm saying that the alternator schematic you posted is a very generic drawing, found in countless manuals and web sites, and it's quite possible that the folks who wrote your manual cut and pasted a schematic from an earlier design alternator. As others have pointed out, you can't tell by looking whether an alternator's IG terminal will turn its output off after it's running.

So.... Your alternator might well be (probably is) *internally* wired differently from that schematic.
 
so i gotta ask........what is the auto industry doing to protect all their electronics. i never hear of a crowbar device. do they have such a thing ?
 
If I do indeed have my "field" switch wired to what is referred to as the IG terminal in all these sources and that shuts down the alternator, will you folks believe me or am I wasting my time and breath here?

Hardly. As Charlie said, it just means the alternator you're using is not internally wired like the posted diagram:

http://www.vansairforce.com/community/showpost.php?p=1215946&postcount=55

Remember, self-excitation doesn't happen until the rotor reaches some threshold RPM. i have no idea what it might be in this case. I asked you to do a IG power shutdown at some RPM higher than idle just to check off the possibility that the thing will not shut down when spun faster.

Along those lines, again checking off the possibilities, do you happen to have a large pulley installed on that alternator?

Mickey checked an alternator here...

http://www.rv8.ch/eggenfellner-subaru-ultra-mini-alternator-2026/

...and reports full control using the IG terminal, but I note his test was to drive it with an electric drill motor, a very low RPM in alternator terms. Again, I'd like to know if IG allows shutdown of that nice little alternator at operating RPM.
 
so i gotta ask........what is the auto industry doing to protect all their electronics. i never hear of a crowbar device. do they have such a thing ?

I believe all modern vehicles have the PCM controlling the field.
 
This thread is making my head spin.

PCM. IG. Left pointing diodes. Shorted transistors. Gate keepers. Somebody missed a memo. I didn't even know there was a memo. But I probably couldn't read it if I got it.

For a simple Gomer like me (SGLM), if I have a Plane Power alternator (PPA) up front and an Earth-X battery (E-X), what else do I need? Is there a brand or part number of something else I need to add for appropriate over voltage protection (AOVP)? A crowbar (CB). A carpet triangle (CT). Claw hammer (AISLE4). A wet tile file (WTF). Whatever it is I need....

Gomer
 
For a simple Gomer like me (SGLM), if I have a Plane Power alternator (PPA) up front and an Earth-X battery (E-X), what else do I need?

If you trust the Plane Power regulator's built in OV crowbar circuit, nothing additional is required except a 5 amp breaker for the field wire.
 
PP alternator

If you trust the Plane Power regulator's built in OV crowbar circuit, nothing additional is required except a 5 amp breaker for the field wire.
BTW, I just tested my Plane Power AL12-EI60/B alternator like I did the other one, and got the same results.

http://www.rv8.ch/plane-power-alternator/

My drill only goes up to 3000 RPM, so it's not exactly like you would have on the aircraft where you're probably seeing closer to 6000 RPM or more, depending on your pulley sizes.
 
Here's the video gents: https://youtu.be/NvQRHuNpjss

Also checked the connections were as I thought:


Verified I had my field wire connected to the IG terminal


Terminal layout

So I just demonstrated in real life what happens when you pull power from the IG terminal on a 27060-16050 ND IR alternator- it stops charging. BTW, engine rpm 1400, alternator rpm about 2200 and charging output around 20 amps if memory serves me correctly.
 
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so i gotta ask........what is the auto industry doing to protect all their electronics. i never hear of a crowbar device. do they have such a thing ?

Not to my knowledge on these vintage alternators, because these OE ND ones almost never have this issue. If this happened in cars as frequently as it happens on RVs as reported here, Denso would be bankrupt long ago and you'd see cars stopped all over the road with fried electrical systems.

I just asked my friend who has worked as a service writer at a large all-makes shop for over 25 years, if he has ever seen an OV problem on these alternators. He said never, only no output which was almost always due to the brushes wearing down to nothing. This experience mirrors my 30 years in working on these and owning many Toyotas with non PCM controlled IR alternators.

Do whatever makes you comfortable.

This experience and the post from another here about junk rebuilds with non- OEM parts that most of the big chains use leads me to think these frequent failures are not due to high temperatures but rather non-OE regulators which don't meet Denso's standards.
 
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My ND alt shuts down when I remove field voltage. Tried it while at 1100 rpm taxi.

At the risk of being chastised for being difficult I?m going to pose another question/option.

First if I understand correctly the ND internal regulator might fail in different ways. Only if it fails in such a way to put buss voltage or ?B? lead power to the field makes it uncontrollable. Any other failure mode could be interrupted by the crowbar circuit opening the field breaker.

Have I got a accurate grasp on this so far?

If a crowbar circuit is installed without a contactor to break the ?B? lead there is still protection from all but the B lead hard short to field?

Are we creating a solution in search of a problem? How often do these things fail?

I think my landings are a bigger threat to the aircraft :cool:
 
Hardly. As Charlie said, it just means the alternator you're using is not internally wired like the posted diagram:

http://www.vansairforce.com/community/showpost.php?p=1215946&postcount=55

Remember, self-excitation doesn't happen until the rotor reaches some threshold RPM. i have no idea what it might be in this case. I asked you to do a IG power shutdown at some RPM higher than idle just to check off the possibility that the thing will not shut down when spun faster.

Along those lines, again checking off the possibilities, do you happen to have a large pulley installed on that alternator?

Yes, I do have a larger alternator pulley and I have a rotor vs. current output chart from this actual alternator at work. I'll look at these next time and report more precise data although I have shut this switch off at over 2500 engine rpm and it still shuts down the alternator (about 3900 rotor rpm).
 
My ND alt shuts down when I remove field voltage. Tried it while at 1100 rpm taxi.

Excellent. Can you post a part number or other model ID?

At the risk of being chastised for being difficult I?m going to pose another question/option.

EarthX probably took a $100,000 sales hit to bring the message that OV protection is required. See post#1.

First if I understand correctly the ND internal regulator might fail in different ways. Only if it fails in such a way to put buss voltage or ?B? lead power to the field makes it uncontrollable. Any other failure mode could be interrupted by the crowbar circuit opening the field breaker. Have I got a accurate grasp on this so far?

Yes.

Are we creating a solution in search of a problem?

That is why we're so interested in the internal connections of the ND alternators.

If wired like the diagram Ross originally posted, it would need a B-lead contactor to ensure protection. On the other hand, if there is no internal connection between the stator output and the rotor field, then merely installing a crowbar or similar on the external field wire should be sufficient.

So far we have three reports of reliable ND shutdown by opening the external field power supply. I'd suggest the next step is to see if any of them incorporate internal OV protection. All it would take is a bench setup with a spinning alternator, two batteries, and a SPDT switch. And a voltmeter.

Hey, the world is full of surprises.
 
Verified I had my field wire connected to the IG terminal.

Just to confirm...IG only, no other connections, like the photo?

BTW, engine rpm 1400, alternator rpm about 2200 and charging output around 20 amps if memory serves me correctly.

The 20 amps at 14 volts tells the tale, more than enough for self-excitement if there was an internal stator-to-rotor path.
 
Don't know if it will help anyone or not, but What Dan is describing is actually illustrated in the pdf that Ross linked much earlier, in post #172. Go to pg 31 (next to last page) and look at 'Regulator Types'. The bottom example, 'grounded regulator', is what we see in the earlier diagram from Ross, that I linked earlier. If any failure causes that transistor in the 'regulator' box to be in a full-on (or shorted) state, you can't exercise positive control over the alternator's output. (To be absolutely clear, there's a lot more stuff in that box than that one transistor. Oh, and the 'regulator' box would be physically inside the alternator, in the models we're discussing.)

The top drawing, 'grounded field', is what we want, for positive control. As long as we can interrupt the B+ feeding the regulator in the top drawing, we have positive control.
 
The bottom example, 'grounded regulator', is what we see in the earlier diagram from Ross, that I linked earlier. If any failure causes that transistor in the 'regulator' box to be in a full-on (or shorted) state, you can't exercise positive control over the alternator's output.

Only true if the field winding has an internal connection to the stator windings, typically via a set of excitation diodes. Mr. Sullivan does not make that clear in http://educypedia.karadimov.info/library/all-alternator.pdf. Actually he doesn't mention it at all, and the page 31 sketch is a poor representation.

The previous post 55 diagram is more realistic; the excitation diodes rectify stator current and feed it into the IG field lead: http://www.vansairforce.com/community/showpost.php?p=1215946&postcount=55

You can find the same diagram in the Bosch Automotive Electrical Handbook and other texts. Here it is a moot point.

The ND alternators Ross, Blain, and Mickey have checked apparently do not have an internal stator-to-field connection. It appears the only source of field current is via the IG terminal. An OV device installed in the IG lead will shut them down if the regulator goes nuts for any reason.

The top drawing, 'grounded field', is what we want, for positive control. As long as we can interrupt the B+ feeding the regulator in the top drawing, we have positive control.

Grounded field is how B&C wires their alternators with an LR3C external regulator. However, they don't interrupt power taken directly from the B+ terminal (nobody does). The OV device built into the LRC3 pops the field breaker.

Grounded field or grounded regulator doesn't matter. Internal or external regulator doesn't matter. The only important question is "Can the field current supply be opened by an OV device?" If yes, the OV device is all that is necessary. If no, a B lead contactor is required, with a OV device to drive it.
 
Respectfully, that's muddying the water. B&C doesn't make an internally regulated alternator; the subject of this discussion.

I submit that the lower drawing on pg31 of the pdf is basically a simplified 'cartoon version' of the schematic posted earlier. Both show the field getting its power from the alternator itself. I just thought it might be simpler to interpret for those not accustomed to reading schematics.

And I question whether being able to control a properly functioning alternator with the IG terminal gives a definitive answer on whether it can be controlled after any/all failure modes of its (internal) regulator.
 
Respectfully, that's muddying the water. B&C doesn't make an internally regulated alternator; the subject of this discussion.

Not to insert myself into this fun little back-and-forth too deeply - but this thread is fundamentally NOT about internally regulated alternators. It's about the requirement for overvoltage protection with Earth-X batteries - by any suitable method.

It devolved into some deep alternator and regulator voodoo, but that's not the point of this thread.
 
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