over voltage protection

[Mike Ice]

Thanks for the replies, but we are getting off track. I know all of the reasons folks don't or do what they feel is the best for their application concerning over voltage protection. And while I agree with you I also see where it might not be the best application for me. I just need some answers to a few specific questions.

Oh and Geico, yes, Birds do ice up, I saw some Ravens with icing the other day, 10 degrees and very foggy and they were all covered in frost, still flying though. The Ravens while iced up were not flying their usual frisky patterns, no rolls or loops, just straight and level.

George, I followed the plan you showed in that picture you posted and now I have another question. Should I take out that ANL fuse that the Z-11 drawing shows installing by the starter relay? Or should I just leave it there?

Once again thank you for you interest and advice.

Mike Ice

[szicree]

What does the Plane-Power OV device actually do when the voltage runs away? Does it trip the breaker? Oh, and also, can anybody tell me what type of alt mount a superior xp360 would have? Thanks.

[gmcjetpilot]

Originally Posted by Mike Ice

Thanks to all for your comments, please continue.

George I had your drawing all laid out and was about to start on it. One question. The boxes labeled M & S in the center stand for Master and Starter relay/contactor,solenoid don't they?

Also, if I follow that drawing would I take out the anl fuse called for and mounted down by the Master/Battery relays, in the Z-11 drawing?

I have never had a prop fly off. Saw one with a crack that had been stop drilled, part 135 operation, flying out of Fairbanks up and down the Yukon river hauling folks and mail.

I have never had a problem with over voltage in my cars or trucks either with an IR Alternator.

The Plane Power Alternator sure sounds better and better.

Mike Ice

Ues master relay and starter relay/contactor. Prop came off, ouch! Yea I think the plane power units are nice. Talk to him and he has a nice product, good design and price is right.


Look if you want to use a CB in the panel, yea the way Bob has it is he goes from alternator (B-lead) to a fuse (ANL) and than the starter relay/contactor terminal on the master relay side (not starter side). It does not really matter where you attach the B-lead as long as it gets to the batter one way or another. The b-lead can go to the main buss, battery or between the master and starter relays. It's all the same.

If you want to keep the ANL fuse than keep it and just forget the CB. I like the CB in the panel for control, warm fuzzy. The BIG fuse under the cowl simplifies the wiring, is cheaper and easier to build and has almost the same level of safety and utility. So either way.

[Rick_A]

I already purchased a 60 amp ANL which is called a "current limiter" in the B&C catalog. I plan to go with the Plane Power Alternator which calls for a Breaker/Fuse in the B lead. So is the ANL than the Fuse for the B lead?

[Mike Ice]

Rick,

The one I have sure looks a lot like a fuse. I bet it is just a different name. But a current limiter by defintion sure sounds like a fuse or circuit breaker.

By the way i am going to take mine out for now and use the B lead to a 60 amp CB (pull able) on the switch panel and not do the over voltage crow bar stuff. That gets rid of one more of those big honkin solenoid/contactor/relay gizmos. The 60 Amp alternator from Van's comes with internal over voltage protection (Voltage regulator).

Mike Ice

[gmcjetpilot]

Originally Posted by Geico266

Over voltage of the "unprotected" alternator cost me $1,000. A freind of mine just spent $2,500 repairing his "urban myth". Overblown? The extra money you spend on a OV protected alt is CHEAP insurance for your electrical system.

YOU LEFT OUT ALL THE DETAILS. I bet it was a external voltage regulator? That's the problem with the rumors. Are you talking ND alternator? What vintage of radios died? What was damaged? This is good info, so please tell all of us more. Keep in mind this is all about internally Regulated Alternators I-VR, ND's specifically.

Originally Posted by Geico266

You state most electronics can handle 18 - 60 volts? Not the new experimental stuff guys are installing in homebuilts. Dynons, Blue Mountain, Garmin handhelds.

That is not true

I called Dynon, their voltage range is as I said 10-30 volts and 60 volts peak. Also I asked Dynon if you had a super nova OV, what would be damaged and what would the cost of repair be? They said the repair would be small, because there is protection to the main circuits!

Garmin, they are made to 1-30 volts, I am reading the manual right now, for a HANDHELD Garmin 195. Operating voltage 10-30 volts. Surge? If its has a regulated power supply it probably can take spikes.

Blue Mountain? I don't know but if they don't have a regulated power supply I would be surprised. If they did not work with a wide voltage range and surge protected I would not buy it frankly.

YOU BRING UP A GOOD POINT. Not all radios are made to this 10-32 volt / 60 volt surge standard. Old radios most likely to not have OV protection, but some new ones don't.

My ICOM A200 com radio is NOT protected. The max for the ICOM is 16 v (according to the manual). I called ICOM and ASKED WHY? They said that is the way it is. I could put a "Transorb" on the CB to protect just the ICOM?

My OLD Collins TDR950 transponder is not protected for 30 volts. I called Collins (now S-tec, a Miggitt co). They don't make TDR950s any more, but I asked a technical guy what damage these transponders get. He said an OV can cause damage but it's usually limited to a few semiconductors on the board.

I would say if YOU did have $100,000 worth of avionics made to 1970's standards I would be more worried about OV.

Originally Posted by Geico266

While it might not kill these items, you still need to send them back to the factory or avionics shop for repairs. Blown internal fuses, cooked display screens, burned out / weakened Optima & Concord batteries. Big bucks and a long down times, both easily avoided with OV protection.

I can't say what happened to you, but guess it was with a Cessna, Piper or Beech and not a ND alternator and modern avionics? You are right OV is NOT good. If your radios or GLASS burn up at 16 or even 18 volts, it's not aerospace quality, at least by today's standards.

Originally Posted by Geico266

Not to mention the possibility of an in flight electrical fire.

Sir I don't mean to be condescending, and I am not very diplomatic. You need to take a deep breath. I might say PROVE IT! What is going to catch on fire? What case have you seen where a ND I-VR caused a fire? There are fires and electrical ones but none involving ND alternators I know of.

I researched this on the "National Highway Traffic Safety Administration's" (NHTSA) data base. NHTSA's data base has ALL auto/truck consumer complaints, manufacturer's service bulletins, letters, trouble reports and recalls. I looked at ALL issues with electrical fires, alternator fires, alternator reliability and spacifically Nippon Denso. There where no alternator fires, induced fires or recalls with the ND brand. ND has no history of any problems in millions and millions of vehicles and decades of service.

There where electrical fires (Ford). There where alternator problems (Hitachi and Ford). The electrical fires associated with alternators usually was the result of something being close, touching the alternator and catching on fire. Faulty wiring or bad connector plugs where also a big problem.

High voltage will not melt the wire, power will. A short to ground on a hot wire will cause the amps to go to infinity. That is bad. The wiring on a 28 volt plane is the same, actually it can be smaller than a 14 volt plane.

The propaganda got out of hand for awhile on I-VR alternators. They are designed to work with OUT add-on OV garbage. The risk is small. The worst case scenario survivable. To avoid fire, keep things away from the alternator, wire it properly and make sure no oil is dripping on it. (no kidding)

Originally Posted by Geico266

If you would like to talk to the people involved in the incidents I mentioned so you can continue your "myth busting" PM me and I'll supply you with the names and cities they live in.

By all means Sir, please lets get the facts out. Lets get the details, RV model, ND alternator model, what happened. Details, details, details, the devils in the details.

I can tell you about 5 cases in planes and 1 in a car where a ND went a little wacky with voltage. I first tell you about the worst two:

Flying a pilot decided to turn the alternator OFF and back ON in for no reason. (Guys STOP that) As soon as he turned it back on the voltage went way high. He turned the alternator back off with the ALT switch. No damage except the alternator, that he had rebuilt. He did not say how high it got because he did not look, just that it was high.

A new alternator , 55/60 amp ND, was installed. During the next flight he smelled something. Down wind of a factory, he ignored it and continued to fly (10-30 min more?). The smell was worse and he finally noticed the voltage was high. This Gent turned the alternator off with the ALT switch, and it responded. There was battery damage (Odyssey). The battery did not leak but was puffed out. The Odyssey battery should not be subject to over 15 volts for extended periods (per the manual). There was no radio damage reported. [Clearly an OV light would have solved the problem. The max voltage was 15 volts (my guess).]

In the cases where the alternator was shut down with the ALT switch, I'd say don't always count on it. That is why I like the CB on the panel. The lesson is have a OV warning light and don't cycle the ALT switch with the engine running. The other cases of OV where mild and basically the voltage was not stable, going up/down with RPM and load, but max Volts where mild.

My RV4's ND had 1000 hours with no problems before I sold the plane. Another guy had the same experience, but the brushes went at 800 hours. It's still going strong. Both of my Acura's with lots of miles and years, both with ND's are still working great.

I've asked Nuckolls and others about their stories. Bob said some guy in a Lancair had $100,000 in damage with a ND alternator? I asked for details: data, time, place, equipment, narrative, analysis or ANY THING; I got nothing but "well I did not see it but I heard." I think it turned out to be a B&C alternator!

Originally Posted by Geico266

I'm not an electronics guy by any means. All I know is the bill, and down time I had to deal with when my alternator failed to full power. Never again for my ship.

OV is COMMON! Happens! BUT...... with 1960's and 70's aircraft alternators and regulators, because those OLD externally regulated alternators are crude they need OV protection. Old planes used old autolite, prestolite, motorola, delco auto parts from 1960's Ford's, Chrysler's and Chevy's.

Originally Posted by Geico266

JMHO & $.02 worth, do what you want.

I appreciate a challenge. Let me know what happened to you. If you want belt and suspenders on your ND alternator I suggest PLANE POWER.

[gmcjetpilot]

Here is the thread I just posted ON how voltage regulators work, how alternators work. Knowledge is power.


http://www.vansairforce.com/communit...ad.php?t=14340

[szicree]

Still wondering what the Plane-Power OV does in the event of a runaway.

[AlexPeterson]

Interesting stuff. Another huge piece which always seems to be missing from the-sky-is-falling OV issue is the effect the battery has on a runaway alternator. Let's just assume the alternator tries to go ballistic. There is a battery in the circuit which doesn't really allow its voltage to get high without putting up resistance (pun intended). In other words, as the errant alternator tries to put out increasing voltage, the battery causes the current to go very high. If there is a circuit breaker on the line, it will trip and the alternator can go ahead and melt itself, but the aircraft circuitry is out of the loop. If someone has a high power, adjustable power supply, it would be interesting to hook it up to a battery like an Odyssee PC680, and see just what sort of current it would take to drive its voltage up to 18 volts, for example. I would suspect it would be waaaay above the 50 amp circuit breaker in my plane, for example. Cranking amperage of several hundred amps only reduces the voltage from 13 down to maybe 8. The same order of current would be needed to bring the battery voltage up by 5 volts as well. If one takes the stated internal resistance of the PC680, for example, and calculates the current necessary to drag it up to 18 volts, the current will be around 700 amps. My little 40 amp alternator running through a 50 amp CB will simply not drive the battery voltage up much no matter how hard it tries.

The important point one needs to keep in mind in these discussions is how pitifully weak the alternator is compared to the battery. The PC680 short circuit amperage is greater than 1800 amps!

I would submit, to much flaming I'm sure, that if the system voltage has gone up to damaging levels, something else is amiss in the wiring design or battery integrity.

[Ironflight]

I must admit Alex, I had never thought of the battery doing that, but it sure makes a lot of sense to me!

And that is what is called "Systems Engineering"....looking at the entire system, and not just analyzing the individual components.

The Valkyrie has an external O/V protection on the SD-8 standby alternator, but relies on the Internal O/V protection of the ND alternator - and I'm comfortable with that.

Paul