Voltage Regulators

Okay boys, I?ve looked but can?t find the posts about regulators. I have a 50 amp Interav alternator and one of their older voltage control systems, circa 1980s. My A&P has confirmed that my regulator is working intermittently and the battery shows signs of boiling over.

During the extensive inspection, I discovered that someone actually took the time to solder a piece of .020 safety wire through the main fuse (between the end caps of the fuse) to compensate for the problem. Now that I?ve replaced it with a real fuse, it keeps burning the main fuses shortly after you turn the alternator switch on, so I?m guessing that the OV relay is toast too? There?s no other signs of any problems that you?d expect to find with a short (see safety wire fuse) so I?m guessing that my voltage control system is deader then Elvis. I?ve got so much RFI that even a hand held radio won?t work until you throttle back to idle. That sounds more like ignition problems to me, but what do I know.

I?ve got to admit that electricity is NOT my thing, so I?d rather replace/update the whole control system and be done with it, rather then chase my tail around fixing electrical problems. Tell me if I?m out of line here with my thinking.

What do you recommend for a voltage control system and where do I get it. At the very least, I have to replace my regulator and that's that. I'd rather replace the 'system' but don't know what to get. Interav?, B&C?, or do I switch back to the good old tried and true mechanical pulse regulator like Zeftronics that puts out tons of RFI as opposed to the modern solid state?

Thanks

Cavy, Zeftronics are solid state. I've used them before and they work great and have great product support. If you are sticking with the InterAv I would contact them. They can probably help you trouble shoot what you have. B&C is good stuff but if you have a front mount oil cooler be prepared to modify the bracket and get a field approval on the installation. If it were me I would contact Inter Av and fix it. Less work and $.

Steve

Take a look at Interav's website. It appears they have quite a bit of troubleshooting information and contact numbers.

http://www.inter-av.com/alternator.htm

So it begins, Cavy?

Chasing around fixing the defects of an old Cub.

Make sure that your charging circuit WIRING is in good shape.

You could buy a whole new system and come up bad again with some bad wiring.

It's tough to troubleshoot this for you using this keyboard, so good luck.

Dave Calkins.

That's a nice trouble shooting guide.

Personal experiense is that a alternator that makes radio noise useually has a bad diode. Something to check? Also when (if?)replacing the Interav regulator, I'd replace the OV control also, I've had them with intermitent problems, (kicking off line for no reason useually), that was cured with a new OV control. Good luck.

I stand corrected about the Zeftronics being mechanical and now I?m not sure which brand I was reading about.

Like I said, I was one of the kids that got to ride the ?special bus? to electronics school. YES I am electronically challenged. I?ve learned over the years (like I need to tell you guys) that little electrical parts are filled with smoke. Seems like every time I get around electricity I accidentally let the smoke out and (as you know) if you don?t get all of the smoke back in there, that little part will never work again.

I printed out the trouble shooting stuff from the Interav site so I guess I know what I?ll be doing this weekend instead of flying.

Thanks all for the tips and links, I?ll let you know how it goes.

It's called PFM (Pure F@%*^# Magic)

Steve

Update.

Following the Interav trouble shooting guide, my voltage readings were nowhere near what they were suggesting. The one and only reading that came close, suggested that I had an open regulator wire.

I studied their wiring schematic and discovered that (1.) I didn?t have the grounding line at the alternator, and (2.) there wasn?t any wire at all between the regulator terminal on the alternator and the regulator terminal on the regulator. Yeah?that would be an open regulator wire.

However, there was a wire connected to the regulator terminal on the regulator. That wire disappeared through the firewall.

What the heck is this? (or words like that) I exclaimed aloud.

Following the regulator wire through the firewall, I discovered that it was connected to the line side of a toggle switch on the panel. Furthermore, they ran another wire from the same lug on the switch, to the line side (buss side) of a breaker, up on the right wing root.

If you follow the path, the regulator terminal on the regulator was wired straight to the positive post on the battery.

I removed the regulator wire from the accessory switch and ran it to the alternator where it belongs, added the bonding strap at the alternator, and moved the wire at the buss to the load side of the breaker. BINGO, the voltages all check out perfectly with the trouble shooting guide for a normal system. It?s now working as it should be.

However, none of this did anything to alleviate my RFI problems, so the saga continues. But at least I saved that beer money by trouble shooting the system.

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There are plenty of IDIOT certified mechanics out in those fields.

And being a rocket scientist doesn't qualify one to work unsupervised on his/her certificated a/c.

Does this installation include the large blue condensor, Cavy?

Dave.

Diggler
Can?t say with any certainty who did it. I?d have to go back through the logs with a microscope and maybe something will show up. This wire that we?re talking about was running to the switch for the smoke system. The smoke system was installed in the 80s. However, the airplane was restored (including a new engine) in 1996, one would assume that it has been running like that for a long time. See the part where I said that there was a .020 jumper wire soldered through the main fuse.

I gave up on trying to figure out why it was done and just went on with fixn it.

DC
Yup, the wire was connected to the same terminal as the positive side of the condenser (spike guard). i.e. battery was connected straight to condenser.

Cavy, There ought to be a 337 form on the alternator installation to make it all legal.

Steve

Interav Alternator

I've got an Interav alternator, regulator, an OV relay with an Electronics International digital volt/amp gauge. I have 2 problems and was wondering if any of you guys had any ideas.

First, because my master switch and aternator switch are one and the same (double pole) after I start the engine I have to cycle the master switch to get the alternator on-line. I suspect that starting is tripping the OV relay. As this relay has no adjustments I don't know what to do. It is only inconvient if I forget and later in the flight have to shut everything down and reprogram the GPS and maybe miss a few "critical calls" on the radio. I realize could install a seperate alt switch but thought somebody might have another solution.

Second, the Electronics International digital volt/amp gauge has an amber light that flickers intermittently even when all indications are normal.

The Interav trouble shooting guide addresses your problem with the OVR. It says that spikes from the starter contacts can trip the OVR. To reset the OVR with a single switch, (I?m guessing here) all you can do is to continue doing as you already stated and turn the whole system off then back on. The guide recommends a sequence of switching, but that?s not really an option for you. I?ll bet you?ve already considered flipping the system off/on after startup as part of your normal startup procedures. God knows I?ve ?flipped off? my system enough times in the last couple of weeks. 0X

After reading the guide, I changed the way I startup and shutdown. Now what I do is crank the starter with just the master on, then turn the alternator on after the motor is running. At shutdown, I kill the alternator, then the master, then pull the mixture. My thinking is that I?m keeping the electronics ?blind? to all the voltage swings that occur during those times.

As for the light?sorry?but heck if I know.

SP
As for the 337?nope?nothing in my possession. I had said in another post that my plane was imported from outside of the USA and got it?s Standard Airworthiness Certificate in May of this year.

My question this time is, if the Interav system was on my plane when the FAA inspected ?it? along with all of the aircraft?s other accessories, ?as a whole?, and the FAA inspectors comment in my log book reads ?I have inspected this aircraft and have issued a Standard Airworthiness Certificate? is not the aircraft (and it?s appurtenances) approved as is?

Cavvy...

It's one of those "Catch-22" things... The FAA did indeed buy off on it for a year with the new A/W certificate... The problem is when your next annual comes up and your IA doesn't have approval for the installation, he's either going to have to get an approval, or take it off... Personally, I'd get the FAA Inspector who issued the A/W certificate to field approve it...

Cavvy...

It's one of those "Catch-22" things... The FAA did indeed buy off on it for a year with the new A/W certificate... The problem is when your next annual comes up and your IA doesn't have approval for the installation, he's either going to have to get an approval, or take it off... Personally, I'd get the FAA Inspector who issued the A/W certificate to field approve it...

Bob, I put this question to my Dad who had a glitch installing the Interav alternator. He is a retired Naval avionics tech, retired mech engineer and an A&P this was his comment:

Steve,
The problem I had was the alternator ran the battery down when the aircraft was parked. It is designed for a system that has a master relay, not just a master switch.
The master relay removes the 12 volts from the Battery terminal on the alternator, the master switch arrangement does not as the full 60 amps from the alternator would have to flow thru it. The problem was that Interav connects a resistor from the battery terminal to the regulator terminal to turn the alternator on when you start up the engine. Unlike a generator that has residual magnetism to kick it off, the alternator does not. The resistor from the Battery terminal to the regulator terminal applies a small current to the rotor coil causes a small magnetic field to start the alternator putting out.
I moved the resistor from the back of the alternator up to the regulator and connected the same Regulator terminal but the other end gets its 12 volts from the aircraft buss. When the master switch is off, there is no current drain from that resistor to the alternator rotor coil. Turning on the master switch turns on the alternator.
I think he has a voltage problem. I always start the engine with the master switch off. It is possible that starting the engine with the master on is causing an overvoltage condition that is kicking in his overvoltage relay. Or he may have a starter solenoid that does not have a diode across the winding to short out the induced field when he releases the starter button. This will cause a momentary overvoltage condition on the buss which is also bad for the avionics. That is why you start the engine with the avionics switch off or the radios off,. If you have a starter relay and a master relay, then you need an avionics switch and an alternator switch to prevent these problems. The above is the reason I like the simple Piper hot push button. You put a starter relay in and you end up will kinds of other problems.

the Interav folks think you need to add a master relay, I don't agree and my system works fine. Yes the battery connection on the alternator is always hot but the rectifier diodes prevent any current leakage.

He said you can call him if needed. e-mail me for his number.

Cavy, I would call Alcor and plead my case. If they are worth a damn they will send you the paperwork and you could get your IA to fill out a 337. The alternator is approved under an STC so all it takes is an IA's signiture. If they won't let me know, I have the needed paperwork I could copy.

Steve

I would try a diode across the relay. The magnetic field might be setting off the overvoltage relay. Cessna's have a diode installed in this manner. Does the OV light come on on your EI Amp/Volt meter?

Steve

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[quote="diggler" When the FAA issues one it basicaly is just doing a conformaity check to see that it conforms to the type certificate. Its up to the IA to say its airworthy at the annual. I dont believe a FAA inspector is signing off a annual when you get a AW certificate. [/quote]

Diggler...

You're almost right on... When the Fed issues an A/W cert. (not a replacement, that's another story), an A&P, doesn't require an IA, signs off a 100 hr. inspection first, then the Fed makes his record entry... Annual's due 12 months later...

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diggler said:

Interesting. I thought the plane would need a annual sign off after the AW Cert was issued. Kinda contradicts the FARs that say a annual inspection is required every year.

Click to expand...

Diggler...

Check out paragraph (a)(2)...

Sec. 91.409 - Inspections.

(a) Except as provided in paragraph (c) of this section, no person may operate an aircraft unless, within the preceding 12 calendar months, it has had --

(1) An annual inspection in accordance with part 43 of this chapter and has been approved for return to service by a person authorized by §43.7 of this chapter; or

(2) An inspection for the issuance of an airworthiness certificate in accordance with part 21 of this chapter.

great educational material on the operation of the Altenator/regulator circuits. I have the same system in my 12 and I was boiling over my battery. I contacted Inerav and they were great to work with. My voltage regulator was charging at nearly 15volts. My cub has very little voltage draw. They went through their inventory and sent me a unit that had a lower voltage limit!! They told me the "spam can" owners would love to have mine!

The trouble I have seen is the early cubs were designed to work with a generator that put out "next to nothing" untill up to cruise RPM. Just updating to an Altenator system doesn't update the starter circuit, and or protect the electronics added.

Tim

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Honestly, no offense Diggler, but:

Any A&P with 3 years of experience can attempt to get Inspection Authorization (IA).

If a guy is "experienced", and has over 3 years as an A&P (as if that was enough time!), Why would he NOT try for his IA?....And why WOULD you hire him?.....And why is he charging $30 less, IA or NOT?

You're just joking, right? 'Cause you don't really know a mechanic WORTH HIRING to work on your a/c who works for $30 less than any other mechanic WORTH hiring to work on your a/c, right? You get what you pay for......if you're lucky!!!

I'm expecting Diggler to come up with a very creative answer that will probably embarass me...he's a thick-skinned SOB, who seems not to care what anyone else thinks...and, yet, I somehow have to like him.

Oh, by the way, Alaska has it's first Republican Governor elected since 1979. Thank you, Alaska, as a collective people.

Dave Calkins.

PS There are plenty of Cubs flying with the same common master/alternator switch that RMREBOB described who don't have to "reset" the alt. after start-up. For the most part, the above arguments/ideas make sense. But, I would caution about the legality and wisdom of adding or subtracting to the system in an "unapproved" manner.

Unrelated, but I have dealt with intermittent, every 10-20 minutes of flight, charging system cut-outs in Cubs with InterAv. systems by replacing defective OVR's. This has occurred in several different Cubs.

Steve Pierce...My understanding of Cessna's installation of a diode from the starter solenoid exciter terminal to ground is that it eliminates arcing at the starter switch (key switch), a common problem that has AD's against it. This has nothing to do with the resistor in the field exciter circuit your father wrote about, nor the rectifier diodes that he spoke of, but will save the switch contacts, for sure. I'm not sure that it would reduce a momentarily high buss voltage.

Some alt. charging systems require a placard stating to never "cycle" or "reset", (turn off, then on) at cruise power (Jasco alt. systems STC'd in the Beaver, C-170, and others). The problem is that the system re-start-up causes the alternator to get loaded-up, inductively, very rapidly, and can shear shafts on certain types of alts. It also illustrates how an alternator can quickly "pull" a high voltage, when told to do so by field exciter current (regulator), and also trip an OVR.

RMREBOB, I would consider a battery voltage problem, like Steve P's dad suggested (weak battery). It may be that a weak battery (low voltage) is called upon to start the engine (making the battery weaker, lower voltage), then the charging system is immediately called upon to recharge the weak battery, but the over-voltage protection is saying "no way, that much voltage will damage the circuit", and the OVR trips the system. The reason the system may function fine after Bob resets the master/alt. switch may be that the removal of the starter load from the battery's voltage, reduces the required charge "pressure" (voltage) that the alt. system "sees" and demands itself to handle. Thus, the alt. system charges happily away until the next morning Bob comes to start his engine, and taxes the battery.

Also, the OVR may be on the low end of it's voltage protection design tolerances, and could get swapped-out.

But check for battery condition first. Start with the cheap and easy things to change, before spending money. I haven't even seen the a/c, so this could all be a guess. Anyone for Website Brain Surgery. ORG/Malpractice???

Dave.

Way to go Frank M.!!

Tim

David M. Calkins said:

Honestly, no offense Diggler, but:
I'm expecting Diggler to come up with a very creative answer that will probably embarass me...he's a thick-skinned SOB, who seems not to care what anyone else thinks...and, yet, I somehow have to like him.
Dave.

Click to expand...

David...

Have to agree with you... Diggler and I seem to be 180 degrees out over religion, politics and relationships, but you can't help but like the guy because he lets you know where he stands, no surprises...

Grasshopper, you must be kidding.

Do you really think you know where Digg. is coming from?

I'm guessing he'd wind-up 180 degrees, just to keep you off-balance.

As of last discussion, I'm 179 degrees out from him on religion, 180deg. on relationships,...............and quite obviously for Alaska anyway, 100 % correct in my political thinking. YEEEE HAAAWWW, we're finally back on track to pull our big 'ol but out of the slump it's been slidin' in.

Dave Calkins.

Idelkete