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Voltage Regulator functionality and connections


pjblittle
(@pjblittle)
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Joined: 3 years ago
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We are putting a Jabiru 3300 (s/n 33A 1041) in a Zenith STOL CH750.

In the installation manual (Rev 7 Dec 2016) page 15 shows a diagram for the regulator plug with pin 5 labeled as Voltage Control to Main Bus, and pin 6 as to Battery +. But on page 54 the wiring diagram shows pins 5 and 6 both going to the main bus. Without knowing what is going on inside the regulator it's hard to figure out how to connect up, for instance, an over-voltage light, and where to put a relay to disconnect the alternator.

Is there a schematic for the regulator? If not, can anyone provide a basic description of the functionality?


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Doug Smith
(@doug-smith)
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Joined: 3 years ago
Posts: 82
 

Hello!

I've just had a look at the wiring diagram in the J Series Technical Manual (JTM001-8) and the note for pin 5 says "J160-C to main bus, other models to battery +" or words to that effect.  Either way will work because the reg basically adds voltage/power to the output wire until the sense wire tells it "enough".  

I don't have an internal schematic of the regulator to hand.  A voltage gauge or warning light would depend on what you're wanting to monitor... if you're wanting to make sure your instruments don't get over-voltaged then you could connect it to the main bus, but if you're wanting to guard against alternator runaway then a connection, suitably fused, to the battery would work.  The diagram on page 268/269 of that manual shows the "standard" way we do it.

Best Regards,

Doug.

 


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pjblittle
(@pjblittle)
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Thanks, Doug. Looking at the wiring diagram you referenced I see that the item 16, a relay, seems to be what is controlling the alternator's output (not the field), with a crowbar module (18) to disconnect in the case of overvoltage. I also note that there does not seem to be a "battery" switch and the battery + is connected full time to the starter relay (which means one less load on the alternator in flight, and one less, albeit small, resistance in line to the starter motor when cranking the engine) - is this correct?

Regards,

Pat


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Doug Smith
(@doug-smith)
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Joined: 3 years ago
Posts: 82
 

Hi Pat,

The standard Jabiru alternator is a permanent magnet type so we can't turn the field off 🙂  The crowbar in that particular variant is to prevent overvoltage damaging instruments.  Yes, we connect the battery directly to the + of the solenoid; barring on-terminal type isolator switches (not really practical inside most cowlings) the extra wiring for the switch would be a net detriment to system safety and efficiency.

Regards,

Doug.


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bennisv
(@bennisv)
Active Member
Joined: 3 years ago
Posts: 16
 

Hi

This is what I have been figuring out regarding the slot 5 an 6 from voltage regulator (yellow wire nr. 5 and red wire nr. 6). 
In my xair hawk with jabiru engine the slot 5 and 6 is jumpered with wire.  That is what they by Xair recommend in the installation manual and I can't figure out why this jumping between 5 and 6.
I find this method little bit weird.  The question is: What is the purpose of the yellow wire in slot 5 ?


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bennisv
(@bennisv)
Active Member
Joined: 3 years ago
Posts: 16
 

hi)

I connected capacitor (22.000 micro, 25 volt) from voltage regulator ( Red wire B+ to Ground) and it killed the RF noise completely.
The RF noise was obviously created by voltage spikes produced by the regulator. The capacitor seems to trap them.

 


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Bobemery
(@bobemery)
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Joined: 2 years ago
Posts: 1
 

I am installing a new Gen 4. 3300 engine in my J250.

I am getting up to 15 volts output, and have checked everything, I am an electrician.p, incudnd different sense points, cleaned a checked earth point and wiring continuity., also bypassing the reg plug as the 10g wires dont fit very well into the spade connectors.

I tried a another new regulator, same thing.  The old smaller regulator works better, supplies lower voltage, about 14v at 2000 rpm.

it does not have the crowbar relay, but I notice that terminals 5 and 6 are joined internally in the regulator on both new regs but not on the old one.

i am frustrated, ready to fly but cant.

any suggestions?

 

R J Emery


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