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Rectifier regulator location help

H

hthaman

Active Member
Has someone installed a regulator recently ?? Per page 46-22 Regulator needs to be installed inside ( F1202B) ( former location F1201B - FWF outside ). Regulator cable and WH-p761 Yellow cable is not long enough to reach inside. Any limitation of installing it at the FWF ( former location ) ???


thanks
 
hthaman said:
Has someone installed a regulator recently ?? Per page 46-22 Regulator needs to be installed inside ( F1202B) ( former location F1201B - FWF outside ). Regulator cable and WH-p761 Yellow cable is not long enough to reach inside. Any limitation of installing it at the FWF ( former location ) ???


thanks
Click to expand...

Sounds like you have the new plans - they are not even posted on the Van's website yet.

There were overheating issues with it I guess and that is why it was moved.
 
Regulator location

I have had to replace one. The local guru says it is in a bad spot because they are sensitive to heat. I am an early builder (#2) and would like to move it except for the harness. Is Vans saying that it should be under the shelf it is now on? It sounds like it is in the new plans. How can I find out about that?
 
Regulator location

I just installed mine in the new location under the panel base. Wires were long enough to accomplish it but adding the shielded alternator wire through the same grommet as the control cables was a bit difficult. The yellow P761 wire goes from behind the firewall down through an existing snap bushing in the panel base.

Check the hole dimensions on the drill template to ensure it actually matches the regulator mount holes.
 
I live in Phoenix and have about 210 hrs and 30 months on my 12. This issue concerns me. How long of a life are people seeing before failure?
 
Heat conductive grease applied to the regulator base will help to transfer heat from the regulator to the aircraft structure. The same grease can be used on spark plug threads.
Joe Gores
 
In my job as an industrial electrician, it was common procedure to use heat conductive grease when installing rectifiers and solid state relays. Open any electronic equipment and notice that heat producing solid state devices will be mounted with either heat conductive insulating gaskets or heat conductive grease or both. The only downside to using heat conductive grease besides the minor cost and labor and mess, is that paint will not adhere to any areas contaminated with grease, which might contain silicon. The rectifier/voltage-regulator in my RV-12 is mounted with heat conductive grease and is securely bolted to the original location on the firewall shelf. It has not failed (yet).
Joe Gores
 
hthaman said:
Has someone installed a regulator recently ?? Per page 46-22 Regulator needs to be installed inside ( F1202B) ( former location F1201B - FWF outside )...........
Click to expand...

Where did you get page 46-22? My regulator bit the dust today and as long as I have to replace it I will go to the new location if I can find the instructions.
 
I installed it last week, Regulator cable and WH-p761 Yellow cable go inside through the right side grommet ( grommet for control cables ) and install the regulator next to the fan area.

thanks
 
I sure would like to move my regulator while I have the top off of the radio panel for the ADSB installation. I may drag my feet a little in hopes that the new mounting instructions make it into Van's RV-12 prints revision section soon. No troubles, so far, but getting that temperature sensitive device into a cooler environment sounds like a winner.

Tom
 
If you will take a good pic or two of that plans page with your phone, or scan that plans page, I'd be glad to post it. Send to Billhollifield AT iname DOT com
 
New regulator in new location, Pages 46-21,22&23, and 45A-04.

Thanks go out to Mitch Gardner for scanning and sending me the four pages from the new plans. I removed the old regulator and found that the pin in the connector from one of the alternator outputs (yellow wires) had overheated enough to melt both the connector body and the regulator housing! That was a surprise, and I suppose explains the behavior I saw before the total failure.

I mounted the new regulator per the revised plans, under the avionics shelf. It seemed nigh on to impossible to me to stuff the shielded alternator cable through the same hole in the firewall as the control cables, so I made a new hole directly below it, and that worked out fine. I printed the drilling template out to scale, and used it upside down on the floor of the avionics bay so I could drill down instead of up. I used heat transfer compound while mounting the regulator, per Joe Gores recommendation.

I checked the area after an hour's flight and the area around the unit was warm to the touch, a good thing, meaning heat is being moved to the larger structure away from the unit. The unit itself was warm, but not enough to burn my hand. Hoping this location is a winner for long life! Surely better than a few inches from the exhaust manifold!

As an aside, I spoke to Van's tech support to ask them to send me the revised plans for Section 46 and they seemed concerned that the plans would not work for a retrofit. I can assure you they do.

Go here and the next entry for pictures.
 
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BigJohn said:
Thanks go out to Mitch Gardner for scanning and sending me the four pages from the new plans. I removed the old regulator and found that the pin in the connector from one of the alternator outputs (yellow wires) had overheated enough to melt both the connector body and the regulator housing! That was a surprise, and I suppose explains the behavior I saw before the total failure.

I mounted the new regulator per the revised plans, under the avionics shelf. It seemed nigh on to impossible to me to stuff the shielded alternator cable through the same hole in the firewall as the control cables, so I made a new hole directly below it, and that worked out fine. I printed the drilling template out to scale, and used it upside down on the floor of the avionics bay so I could drill down instead of up. I used heat transfer compound while mounting the regulator, per Joe Gores recommendation.

I checked the area after an hour's flight and the area around the unit was warm to the touch, a good thing, meaning heat is being moved to the larger structure away from the unit. The unit itself was warm, but not enough to burn my hand. Hoping this location is a winner for long life! Surely better than a few inches from the exhaust manifold!

As an aside, I spoke to Van's tech support to ask them to send me the revised plans for Section 46 and they seemed concerned that the plans would not work for a retrofit. I can assure you they do.
Click to expand...

Fantastic!! Hey John, any chance of getting a copy of the plans?? I sure would like to move mine while in the process of doing the ADSB mod.......Tom
 
Some nice folks mailed me pics of the new plans pages showing the modified voltage regulator location. Here they are. Sorry about the delay!

Pg%252045A-04.JPG



Pg%252046-21.JPG


Pg%252046-22.JPG


Pg%252046-23.JPG
 
Blast tube alternate usage?

I was thinking about this today and I read somewhere that with the relocation to the inside cabin, the rectifier blast tube is abandoned.....

I was wondering if you could somehow relocate the blast tube to redirect air between the oil cooler and the muffler to aid in keeping the extra warm air away from the back of the oil cooler?

I mean there is a pretty good airflow thru there already and of course many have done the cowling oil cooler 1-1.5" forward mod....

But if you could route the tube thru the front and perhaps wrap it in heat protectant hose?

I dunno.
 
cactuspilot said:
I was thinking about this today and I read somewhere that with the relocation to the inside cabin, the rectifier blast tube is abandoned.....

I was wondering if you could somehow relocate the blast tube to redirect air between the oil cooler and the muffler to aid in keeping the extra warm air away from the back of the oil cooler?

I mean there is a pretty good airflow thru there already and of course many have done the cowling oil cooler 1-1.5" forward mod....

But if you could route the tube thru the front and perhaps wrap it in heat protectant hose?

I dunno.
Click to expand...

In the big scheme of the things I'd say don't worry about it now. If you want redirect the tube to blow on the engine driven fuel pump, that would be easy. Just keep pushing ahead to get Airborne. Then later if oil temp is a problem you could go back and look at it. :)
90% to go!
 
The engine driven fuel pump is right behind the open air inlet. Doubt adding the blast tube would do anything!

If I had it to do over I would do the cowling mod as part of initial construction. A bit of a chore once painted. I don't see it as a "per the plans" issue any more than modifying the duct so that it is not so close to the pilot side forward exhaust pipe. Its just good workmanship to ensure proper clearance.
 
I sure am glad I did this correction on the cowling. I have been flying in southern AZ, CA, NM and CO without any oil temp problems whatsoever. I do carry a small piece of cardboard in the plain that covers the oil cooler to speed up oil temp build-up when starting the engine on cool mornings though. Now that we are heading into winter, this will be necessary to not waste time on the ramp waiting to reach the magic oil temp limit. A partial cooler cover with aluminum tape is necessary when we reach lower temps to maintain a reasonable oil temp at cruise altitude during the winter time.
 
Be aware that there is no way to shut off the Rotax dynamo other than stopping the engine. Whenever the engine is running, the yellow wires from the dynamo are live with AC voltage. Shutting off the master switch does not shut off the AC voltage. Although unlikely, it is possible for those 2 yellow wires to short together and cause smoke or fire in the cockpit (if that is where the regulator is located). The dynamo wires should be well protected where passing through the firewall.
Joe Gores
 
Mich48041 said:
Be aware that there is no way to shut off the Rotax dynamo other than stopping the engine. Whenever the engine is running, the yellow wires from the dynamo are live with AC voltage. Shutting off the master switch does not shut off the AC voltage. Although unlikely, it is possible for those 2 yellow wires to short together and cause smoke or fire in the cockpit (if that is where the regulator is located). The dynamo wires should be well protected where passing through the firewall.
Joe Gores
Click to expand...

I spoke recently with a builder with lights and around 300 hours and he said he has blown 3 of the regulators with the cooling tube, until the battery help desk suggested buying the proper charger and then putting the charger on the battery for 3-4 days once every 3 months regardless of how much it is flying.....he started doing that a year ago and has had no problems since. FWIW.
 
cactuspilot said:
I spoke recently with a builder with lights and around 300 hours and he said he has blown 3 of the regulators with the cooling tube, until the battery help desk suggested buying the proper charger and then putting the charger on the battery for 3-4 days once every 3 months regardless of how much it is flying.....he started doing that a year ago and has had no problems since. FWIW.
Click to expand...

Okay John, So what is the "proper charger" that you mentioned.......Tom
 
About 600 hours and 9 years on my 914. The regulator is heat sensitive. Be sure it is mounted on a metal surface if possible and use thermal compound as suggested by others. Direct cooling air to it if possible and be sure the air has a way out. Try to keep the current draw no more than 15 amps, 10 is better. The ground connection on the mounting stud is sometimes problematic because the hole in the regulator is big (3/8") and the mounting hardware is usually #8 or #10 so it is a sloppy fit. I drill a hole in the fin area and connect the ground there with a #10 screw and the correct size ring terminal. Put heat sensing labels (Thermax from McMaster) on the regulator and both your ignition modules. Rotax specifies no more than 80 C.

Jim Butcher
 
I shouldn't tempt fate by saying this, but after 250 hours and nearly three years in the Phoenix heat I have not experienced any regulator issues. I'm wondering if this is a fleet issue or a manufacturing issue that produced some regulators prone to failure. Does anybody know how common these failures are?

Rich
 
RFSchaller Has anyone tried an alternative like this one. The price looks good, and the specs seem comparable.
http://www.aircraftspruce.com/catalo...clickkey=59750
Click to expand...
That regulator is made for 3 phase. The Rotax dynamo is single phase. Click on Aircraft Spruce's Q+A and it says that it will not work on the Rotax 912.
Some people have used John Deere part number AM101406 with success. Voltage regulators on eBay for $45: Keep in mind that other brands of regulators have different mounting hole and electrical terminal locations. So they are not plug and play. The Rotax plastic connector will not fit. The installer will have to drill new mounting holes and switch the electrical terminals around. The voltage output of the John Deere regulator is a few tenths higher than the Rotax regulator, but I do not think that matters.
 
Joe,

Yeah, that was a Homer Simpson moment "Doh!"

I made the mistake of assuming the generator was Ike the one on my HKS 700. You are, of course, correct. ROTAX uses single phase.

Rich
 
After reviewing the "evidences" I have some doubts about this regulator relocation business. I have the feeling that in the new location, the regulator receives less rather than more cooling air... That is if the blow tube works as it is supposed to. Forcing outside air over the regulator fins should be more effective than letting inside cabin air cooling the fins by convection, period!
Which leads me to conclude that either:
- The failing issue is not temperature related
- Or the blow tube is not doing what it's supposed to do
There are indeed uncertainty about the distribution of the air flow from the left inlet between the cylinders cooling shroud and the blow tube. This uncertainty is depending on the fiberglass shroud adjustment and the blowing tube entrance positioning, both being builder's dependent.
IMHO, assuming that the issue is temperature related, a better solution would be to relocate the blow tube entrance to a new inlet drilled on the side of the existing left cooling inlet on the lower cowl.
 
Keep in mind that regardless of how efficient the regulator cooling tube is, it is needing to over come the fact that the regulator is mounted directly in the outflow of the engine coolant radiator only a short distance away. And that even if it wasn't in the heated outflow of the radiator, there is a huge difference in ambient temp, between almost anywhere in the engine compartment and the cockpit.
 
rvbuilder2002 said:
Keep in mind that regardless of how efficient the regulator cooling tube is, it is needing to over come the fact that the regulator is mounted directly in the outflow of the engine coolant radiator only a short distance away. And that even if it wasn't in the heated outflow of the radiator, there is a huge difference in ambient temp, between almost anywhere in the engine compartment and the cockpit.
Click to expand...

Assuming that the pressure created by the outflow of the coolant radiator is higher than the pressure of the blow tube, then there is even a better solution: connect the blow tube to the wall of the radiator cooling channel, upstream from the radiator. It may be that due to the larger size of the air intake of the radiators'channel, the pressure in this channel is higher than the pressure at the current intake of the blow tube. This modification would be very easy to do.
I further believe that if the air pressure in the regulator cooling tube is adequate, the ambient temperature under the cowls does not matter as this cooling stream will push the warm ambient air away.
I believe that VANs has the wherewithal to check these assumptions by installing air pressure probes at the different points in question and making measurements on the ground and in flight.
 
rvbuilder2002 said:
Keep in mind that regardless of how efficient the regulator cooling tube is, it is needing to over come the fact that the regulator is mounted directly in the outflow of the engine coolant radiator only a short distance away. And that even if it wasn't in the heated outflow of the radiator, there is a huge difference in ambient temp, between almost anywhere in the engine compartment and the cockpit.
Click to expand...

Especially when the regulator is also receiving radiated heat from the exhaust pipe only a few inches away. That pipe is the hottest thing under the cowl at exhaust gas temps of well over 1000 degrees.
 
BigJohn said:
Especially when the regulator is also receiving radiated heat from the exhaust pipe only a few inches away. That pipe is the hottest thing under the cowl at exhaust gas temps of well over 1000 degrees.
Click to expand...

Agreed. IMO it is a lose/lose situation in that location.
 
VR issue

I hope that WingedFrog is right. I just finished moving my VR. I moved it to the left about 6 inches, made a heat shield to protect it from heat off the radiator, moved the blast tube to the air tunnel that goes to the radiator. I don't think that there is much air pressure in the air tube that cools the cylinders. I might be wrong (I'll find out) but I believe that a good solid stream of cool air going over the regulator has to be better than moving it to the inside of the cabin where there is little to no air flow.
 
Would this help?

Been watching this discussion and will place my regulator inside as per Van's. Just wondering how tough it would be to mount a computer fan under there with the regulator? Would this be effective? Do they draw too much juice to be effective?
 
Harvey L. Sorensen said:
I hope that WingedFrog is right. I just finished moving my VR. I moved it to the left about 6 inches, made a heat shield to protect it from heat off the radiator, moved the blast tube to the air tunnel that goes to the radiator. I don't think that there is much air pressure in the air tube that cools the cylinders. I might be wrong (I'll find out) but I believe that a good solid stream of cool air going over the regulator has to be better than moving it to the inside of the cabin where there is little to no air flow.
Click to expand...

I will know soon if I am right: I received today a set of Wahl Temp-Plate (the world's smallest temperature recorder) that I will stick on my regulator in a series of tests. My current guess is that this regulator has a component quality problem that may be aggravated by high temperature. As a case, I submit this picture from BigJohn:
http://www.mykitlog.com/users/display_log.php?user=BigJohn&project=639&category=0&log=198056&row=2
It shows damage that are way beyond overheating, this is sign of a short circuit.
The new location is not the solution because:
- Convection cooling is less effective than forced air cooling
- Convection cooling "upside down" is even worse because in the new location the hot air has nowhere to go but down.

This make me believe (and I hope I am wrong) that VANs "engineered" this solution by the seat of their pants rather than with tests and trials which is what I intend to do.
For those that may be interested, this is the web site that sells the Wahl Temp Plates: www.palmerwahl.com
The strips I got (10 for $31) are marked 71, 82, 93, 104 deg centigrade which is a good spread around the max temp indicated by the regulator manufacturer.
 
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Some Musings on RV-12 Regulator Reliability

While I am not immediately involved in the reliability problems related to the RV-12 voltage regulator I do have some experience in making electronics work in similar environments and have a couple of observations.

My guess is that the blast tube is indeed providing enough cooling to keep the regulator in a temperature range that would not cause reliability problems in flight. That said, the place that I would look for the thermally induced stress that is putting the electronics on the slippery slope to failure is after the flow of cooling air is shut down and before the cowl interior has returned to ambient temperature. If I were investigating this I would instrument the regulator with thermocouples and perform several mission profile tests (start-up, taxi, flight, taxi, and shutdown) in order to characterize the actual environment present. (If you want to bring your RV-12 to Redlands, CA for a day we may be able to put something together to perform this test.) If I were to make a hypothesis on the failure mechanism I would be looking at what happens to the temperature after engine shutdown. I have seen problems in the past that were believed to be a result of convective (air) flow cooling that turned out to be the radiated (IR) energy off of engine components in particular exhaust (pipes and nozzles). The regulator may be heated well beyond the specified non-operating temperature specifications for its components and the assembly overall. This would indeed impact the overall reliability of the units as have been experienced.

At a minimum I would suggest that some form of barrier, say a sheet metal panel, that would block any IR energy between the exhaust and the regulator would be a minimum implementation (I have not seen the actual installation so that may already be the case). As a secondary measure I would attempt to try to find a way to provide some way of convectively cooling the regulator assembly after shutdown.

Based on some of the experiences that have been posted I would say that moving the regulator away from the engine is a good idea. Placing it inside the cockpit will eliminate most of the heating from direct radiation. In addition the temperature rise after shutdown will just be from the regulator and some solar drive but not much from the engine. The use of the avionics shelf along with some heat sink compound should be a great improvement to assist the heat sink assembly in dissipating the thermal energy. My guess is that there is enough air moving around the avionics shelf between the existing fans and natural convection that an additional fan would bot be necessary.

Here is a link to a silicone free thermal conductive compound with a temperature range of (-40? to 320? F) that may be of interest.
http://www.mcmaster.com/#3883k24/=v0efs5

This is a silicone based thermal grease that has a bit higher temperature range (-40? to 400? F) that we have also used in similar applications.
http://www.mcmaster.com/#10405k79/=v0egyf

my 2 cents from the sidelines,
larosta
 
WingedFrog said:
- Convection cooling is less effective than forced air cooling
Click to expand...

I agree.

But I also know that convection cooling in an environment of 70 - 90 F. air can be more efficient than forced air cooling of a device that is mounted to a hot firewall, within a high heat high volume airflow (from engine radiator), in somewhat close proximity to one exhaust pipe, and being fed by a low volume cooling hose that is only moving air on the fin portion of the device (the main body of the regulator is outside of the cooling shroud and within the blast of the radiator exit flow).

And keep in mind the cooling airflow being ducted to the regulator when it is mounted in the engine compartment, is probably not much cooler than the ambient within the cockpit, by the time it reaches regulator.

Also, the new in cockpit regulator mounting location was selected very strategically. It is adjacent to one of the avionics cooling fans, so that if time in service shows that owners operating in extreme temp environments have the need, a simple shroud can be developed, that will use the cooling fan to move air across the fins (but I don't think it will be necessary).
 
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Be careful about drawing definitive conclusions from my melted contact photos. I am inclined to think the obviously overheated single contact was really not due to the regulator overheat problem, but may have been caused by a partially seated terminal end, resulting in a small area of contact, which would overheat.

Yes, my regulator did fail, but that failure could have been due to the more general overheat problem, unrelated to the single melted contact.

As I have said before, it will be interesting to see what the life expectancy is of the regulator installed in the new location.
 
BigJohn said:
Be careful about drawing definitive conclusions from my melted contact photos. I am inclined to think the obviously overheated single contact was really not due to the regulator overheat problem, but may have been caused by a partially seated terminal end, resulting in a small area of contact, which would overheat.
Click to expand...

WingedFrog said:
I submit this picture from BigJohn:
http://www.mykitlog.com/users/display_log.php?user=BigJohn&project=639&category=0&log=198056&row=2
It shows damage that are way beyond overheating, this is sign of a short circuit.
Click to expand...
I didn't comment in my other post because I didn't want to point a finger at his possible mistake, but since he did himself I figure he wont mind.


I agree with John.
The photo shows a classic example of what can happen with a high current connection that has some resistance from poor connectivity or lack of contact area, for the amount of current that is being passed.

I said can, because it could be caused by other factors also, but given the explanation that John gave, I assume he found female spade connector pushed back into the connector body (indicating it wasn't engaged on the regulator connector fully).
 
rvbuilder2002 said:
I didn't comment in my other post because I didn't want to point a finger at his possible mistake, but since he did himself I figure he wont mind.


I agree with John.
The photo shows a classic example of what can happen with a high current connection that has some resistance from poor connectivity or lack of contact area, for the amount of current that is being passed.

I said can, because it could be caused by other factors also, but given the explanation that John gave, I assume he found female spade connector pushed back into the connector body (indicating it wasn't engaged on the regulator connector fully).
Click to expand...

Well actually, I couldn't tell for sure, because the terminals were welded together and getting them apart was a bit of a struggle! But it seems quite likely the cause was a partially seated terminal. My bad.

At any rate, I don't think the contact problem caused the regulator to fail, because the failure symptoms were consistent with others. Not kicking in until higher RPMs etc., then total failure. IMHO the new location away from the radiated heat from the coolant radiator and especially the exhaust pipe is a winner.
 
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I have absolutely no data to support this theory, but I have wondered if the "heating up" of various components such as the regulator and the ignition modules could be happening after shut down. I have replaced both of these items as have others. While flying and taxiing there is some air passing through the cowling, but upon shut down, airflow stops but the engine remains very hot. My thought is that this is when the damage may be happening. I have started popping the oil door open as soon as I lift the cowling and the air that escapes is HOT!:confused:
 
WingedFrog said:
I will know soon if I am right: I received today a set of Wahl Temp-Plate (the world's smallest temperature recorder) that I will stick on my regulator in a series of tests. My current guess is that this regulator has a component quality problem that may be aggravated by high temperature. As a case, I submit this picture from BigJohn:
http://www.mykitlog.com/users/display_log.php?user=BigJohn&project=639&category=0&log=198056&row=2
It shows damage that are way beyond overheating, this is sign of a short circuit.
The new location is not the solution because:
- Convection cooling is less effective than forced air cooling
- Convection cooling "upside down" is even worse because in the new location the hot air has nowhere to go but down.

This make me believe (and I hope I am wrong) that VANs "engineered" this solution by the seat of their pants rather than with tests and trials which is what I intend to do.
For those that may be interested, this is the web site that sells the Wahl Temp Plates: www.palmerwahl.com
The strips I got (10 for $31) are marked 71, 82, 93, 104 deg centigrade which is a good spread around the max temp indicated by the regulator manufacturer.
Click to expand...

Excellent - facts and data for decision making. Be careful that the temp-patches are not exposed to direct radiated energy from a high temp source, that will heat the surface and give an erroneously high reading. You probably already know this - and are placing some on the back too, so the core temp can be attained.

Good going, there is NOTHING better than good data.
 
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