3300 Electrical Problems

[danstee]

We've been having a few electrical problems with our 3300 Engine (installed in a Jabiru). It started with a burnt out (old style 3-wire) alternator. Replaced that with the newer 2-wire alternator and a new regulator. I now find that I'm not getting charge (only 12 volts on the volt meter). I have been using a tacho pickup that counts flywheel teeth, but recently shifted to one picking up from the alternator wires, and can't seem to get a pulse.

 

I haven't yet run a multimeter over the alternator output (a trip out to the airfield tonight), but that will be the next step. This should tell me if the alternator or the regulator is the problem. I looked at the alternator wires, and they appear OK (when we burnt the last alternator, you could see blackened wire).

 

Has anyone had similar problems? What is the recommended solution? Should the PowerMate regulator help?

 

Any helpful comments greatly appreciated.

 

Thanks in advance

 

David

 

 

[Guest brentc]

When you check the voltage when the engine is running, how many RPM do you have on the engine? You won't get charge until around 1,500rpm+ Many people have been caught by this as they jump start the engine, run it for 20 mins or whatever then it won't start again because it's not charged. Mine probably sits on 12 volts or even less at idle depending on what is turned on. My radio even indicates low voltage at a low idle.

 

It's a pretty simple system with the 2 wires so you might not have a problem at all.

 

 

[danstee]

Brent, thanks for the really fast reply. I'll make sure I have the RPM up a bit when I check the alternator output. I did think that alternators were supposed to put out at least 17vAC or so even at idle, although the Jabiru ones could be different...

 

Thanks again for your input.

 

David

 

 

[Ross]

This may not be applicable to you.

 

On an early Jabiru build the builder saw that the output from the alternator were both marked as either positive or negative (I don't recall which) and I am not going out to the garage to see what they are marked in my book.

 

So he decided to join both wires before they made it to the rectifier not realising that they were outputting AC power and I surmise 180 degrees out of phase with one another meaning I surmise again that each wire was alternatively positive and negative but actually opposite to what was happening on the other wire.

 

The result was a burnt out alternator or a change of colour of the coil wiring in the alternator!

 

Regards

 

 

[danstee]

More information

 

Ross & Brent, thanks very much for your input. I have some more information after visiting the plane yesterday evening. Here are the readings I obtained from the Dynon EFIS, the VDO volt meter, and a multimeter reading AC voltage direct from the alternator:

 

Alternator Dynon VDO

 

Idle (950rpm) 7.1acv 11.9v 12.1v

 

High (2100rpm) 17.8acv 11.9v 12.1v

 

When taking the 'high' reading I didn't dare push the RPM over 2100 with only chocks restraining the plane. On the weekend I'll do some fast taxiing to see if the regulator kicks in at higher RPM, which has been my experience in the past. I have now also achieved a pulse from the alternator to obtain a tacho reading, which is certainly a step forward.

 

An initial prognosis might be:

 

1. Alternator seems to be working

 

2. Jury out on regulator, need to test at higher rev

 

3. Jury out on battery, needs some time charging before we can determine if its OK

 

Any other thoughts from the learned panel?

 

Thanks again for your help so far.

 

David

 

 

[Guest brentc]

FYI - my radio voltage display records a max voltage of 13.8-13.9 at full power (it probably should be more than that).

 

It looks fairly convincing that your alternator is working but you're not getting the volts to the Dynon. Sounds simple enough based on that, I'd say that you haven't wired up the alternator properly to the regulator after you changed from the 3 wire alternator to the 2 wire model.

 

That's my guess anyway! You need to get hold of the Jabiru wiring diagram to see where you've gone wrong. Also your regulator may not suit the new alternator type. I'm thinking that you might need to worst case bridge a couple of the regulator wires together. If it's the wrong regulator it's probably not worth much as it's from a Kubota tractor if memory serves me correctly.

 

It's not a complex system so should be easy enough to work out.

 

Whilst I built my own Jab and am not a wiring guru I could be floating around on Saturday, I could head out that way and compare set-ups with you if you are still stuck.

 

Good luck.

 

 

[Ross]

Volts for your radio

 

I was under the impression that a regulator for a "12 Volt" lead acid type electrical system should produce a maximum voltage of 13.8 volts or was it 13.6 volts.

 

So radios for "12 Volt" systems were designed to put out a full strength signal when run on "14 Volts" DC not 12 volts or 10 volts.

 

A radio radiates energy according to the square of the available voltage.

 

So a drop in voltage say from 13.8 volts down to 10 volts could represent about a 48% drop in radiated power.

 

13.8 volt down to 12 Volt could cause about a 25% drop in radiated power.

 

Some glider pilots used to add an extra cell to their 12 Volt batteries to keep the voltage in the high end (14 V) longer and above the voltage where a relay in the system might stop working.

 

On the alternator front

 

This might be pertinent depending on what rectifier and regulator is being used but don't ask me which ones are the guilty party as it was a while ago. I don't know if it is still a problem with some set ups!

 

I remember that on some tractors there were some alternator regulator combinations that on starting up a motor would not produce a charge until the motor RPM was around 1600 RPM as indicated by an alternator warning light going out.

 

Remember that when alternators were first fitted to replace generators they generally had to have smaller belt drive pulleys so that they would run a lot faster than the generators that they replaced.

 

On the tractors above, the alternator would continue to charge then even if the motor RPM were dropped back to a normal idling speed of around 1100 RPM or less. So it was normal practice (not necessarily best practice) to run the speed up until the alternator cut in then drop it back and let the motor do a fast idle for a while to warm up.

 

Motors that normally run for most of their time close to their maximum power like tractor and aeroplane engines possibly could run their alternators at a lower speed than the case where engines run a fair bit of their time at low speeds but could also do some duty at high engine speeds. It might extend their life significantly.

 

Regards

 

 

[Derby]

Hi my J400 shows 14.2 to14.5v at anything over 2200 to 2300 revs.

 

 

[Captain]

Mine reads similar to Derby's, but from about 2000 up.

 

David ........... I have a PowerMate fitted to the 3300 in my J230 (and am very happy with it) so I have the standard voltage regulator still in the shed unused. Drop me a PM if you want me to dig it out & stick it into the mail to you (gratis of course).

 

Regards Geoff

 

 

[danstee]

Electrical Update`

 

Hi all,

 

Firstly I'd like to thank everyone for their input, its great to see how much support there is out there, especially Brett who offered to drop into Riddells and Captain for the offer of his old regulator.

 

I ended up deciding to fit the PowerMate regulator, which I did last weekend. I'll give the plane a run this weekend to see if we've solved the problems. One strange thing:

 

The alternator seems to be working OK, generating AC voltage at the levels expected at various RPM. However, the tacho pickup on the Dynon only works on one of the 2 alternator leads, not the other. I mentioned this to a guy from Jabiru who said not to worry about it, and that it might have something to do with the phasing of the output of the alternator. The read from the other lead seems accurate.

 

I'll give you an update after a run this weekend (weather permitting).

 

Thanks again for all your help.

 

cheers

 

David

 

 

[Guest ppcmacgyver]

Hello all. newbie to the forum here. I have similar issues with the 3300 I just had the powermate installed because of radio noise (like the squelch was inoperative static all the time) and my battery was going dead. I had an avionics shop install it because i thought the Icom 200 was going bad or had issues. however i left the avionics shop and i still have the same issues. (even at full throttle) the voltage shows about 12 volts and goes to 13.8 around 2600 rpm. so i am guessing that the alternator is working however i still have the noise an i was thinking i would have more voltage. when i recieved the plane (it was purchased) i had no radio noise, and it just got progressively worse. any ideas there?

 

 

[jetboy]

people have reported gradual worsening of noise caused by the distributor rotors getting wobbly on their shafts. The original carbon powder HT leads dont help also, factory new engines now have something better. As plugs wear (around 200 hrs) the gap widens which may contribute to increased HT noise. If your not running certified category, you can swap to DR9EA or the ND iridium plugs for better results (sit down while you price these)

 

of course, your noise may be from something else.

 

Ralph

 

 

[frank marriott]

A 12 volt radio (solid state) normally runs on a 10volt regulated supply rail (internal) so any voltage nominally between 10 and 13.8V supply voltage should not change the performance of the radio. Hope that helps.

 

 

[Guest brentc]

Macgyver, you need to grab a handheld and try it near or in the plane and see what if any inteference you are getting on it. At-least then you can discount your regulator from the equation as the battery powered handheld won't be affected by the power supply. If it's plugs, the handheld will still be affected.

 

 

[xair1159]

David,

 

I have a Powermate on a 2200 engine and had similar tacho problems with a Grand Rapids EIS. The EIS manual said that the tacho would work on one alternator lead and not the other. Tried swapping them but still no go. Spoke to Claus at Powermate who came up with the answer - I assumed both the Powermate input leads were floating - wrong! One is earth, or very close to it, so the tacho lead has to go to the other one. Easy to measure with a meter on resistance, one side is infinity, the other zero or very low ohms. This all means you have to choose the right alternator lead and the right reg. lead, giving you four options to sort through.

 

Nick

 

 

[Guest ppcmacgyver]

Thanks Guys. I will try the hand held and see if i have issues. also the engine has 90 hours on it so i am guessing that the plugs are ok (never know). by HT leads i assume you mean the spark plug wires? yes it's an experimental so i am good to go on testing all the options.

 

 

[jetboy]

Yes Macgyver HT leads = spark plug leads. Sometimes they work out of the distributor and start arcing there too, if they had been put on with air trapped under the rubber. You can measure each one with an ohm meter, should be around 5,000 - if there is no reading at all there might be a missed end connection arcing. At 90 hrs the plugs should not have changed enough to make new noise. A loose distributor rotor is still a possibility.

 

There is a lot of other stuff that could be the source, some GPS make lots of noise on various frequencies, carb should have a factory grounding wire to the engine block, scat tubes where the wire rubs on things, alternator wires burning up at their connector.

 

If it still traces to ignition noise, I have some fairly technical test results on the Yahoo group here:

 

http://groups.yahoo.com/group/jabiruengines/files/Radio%20noise/

 

The P leads to the coils (from the ignition switch) seldom are a problem, they are normally shielded leads but you could check that the braid is still grounded at the coil ends.

 

Ralph