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Dead PlanePower alternator- internal bits and wiring?

chris mitchell

Well Known Member
I have an alternator that died a while ago (on the apron at a French airport - but that's another story). Trying to get it repaired is a bit of a nightmare. Does anybody know the part number of correct voltage regulator and does anyone have a wiring diagram for the internal workings?

The wretched thing has been repaired once already, still doesn't work and getting it back to PP/Hartzell is going to be a chore which I would rather avoid (shipping from UK to US, ddealing with customs, etc etc etc. So any information will be gratefully received.

Many thanks

Chris
 
Chris,

My experience has been that the internal voltage regulator is proprietary and not available from any source including Plane Power. A very well regarded local shop kept mine for three weeks trying to locate the correct part and finally gave it back to me unrepaired. A call to Plane Power resulted in the answer, "We don't offer parts or overhaul."

The PP alternators are basically throw away items once that element has failed.
 
The VR from a few years is marked 6621, and appears to be modified by Unipoint or perhaps Plane Power. The number is not listed in Unipoint's regulator catalog. The apparent mod is a jumper wire from the board to a brush terminal. It may be possible to order a 662 and make the mod, or simply install one of the other 66xx regulators and forgo whatever the jumper enables.
.
 

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It seems the common failure for these alternators is broken wires on the stator. May want to give a look inside before modifying the VR. Several posts on the subject.

Larry
 
AircarftSpruce sells the regulator:

11-1043 HARTZELL PLANE-POWER REGULATOR BRUSH ASSY

A compatible rectifier block is INR724.

I keep one of each in my toolbag, they are easy to swap.

Lenny
 
Thank you for help!

Thanks guys that's all helpful. Considering how much the thing cost I'm disinclined to throw it away!

Dan -H - interesting about the connection from the board to the brush terminal. The technician who has it at present is curious about that. We have been on to PP/Hartzell. Waiting for a reply....

When/If I get an answer I'll be sure to post it here.

Thanks again

Chris
 
I'll be very interested in their reply since I was told there were no repair parts or overhaul available. That came directly from Plane Power. Also, is the ACS regulator modified with the jumper? If my memory is correct, the regulators are modified by Plane Power and they wouldn't sell a modified replacement. I also seem to remember that the board and the jumper were encased in some sort of potting material.
 
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Yes and I believe that Bob Nuckolls wrote about this modification. If I remember correctly, that modification creates the overvoltage protection that is internal in the Plane Power alternator. It's the reason I asked if the ACS regulator has the modification. Hope it does as I've got a bad one on my shelf that I'd love to get fixed and Plane Power said parts were not available.
 
Can someone please confirm that the regulator from ACS DOES have the Plane Power modification? Perhaps, since some carry the ACS part as a spare, a photo of the part? Just seems very strange to me that PP would tell me that the parts nor any overhaul was available and that a very well known (locally) overhaul facility also told me the parts were not available after searching for a couple of weeks.
 
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What voltage should I seeing on my efis

I have the plane power 60amp internally regulated alternator from around 2009. I highest volatage I see is 13.2 on the efis with master on/avionics. I see 14.2 if I switch on the E-buss. Is this normal?
 
Todd,

Yes, it's normal. Your efis is likely fed through the ebus diode, which creates a voltage drop. Once you turn on your ebus switch it sees bus voltage.

You can improve the voltage drop by using a Schottky diode on the ebus.

Lenny


I have the plane power 60amp internally regulated alternator from around 2009. I highest volatage I see is 13.2 on the efis with master on/avionics. I see 14.2 if I switch on the E-buss. Is this normal?
 
The regulator sold by Spruce is the same thing as the original. It's also a Hartzell part number. I replaced mine with one from Spruce. Looks exactly the same with the wire included. They give you the whole assembly with brushes and everything.

Lenny

Can someone please confirm that the regulator from ACS DOES have the Plane Power modification? Perhaps, since some carry the ACS part as a spare, a photo of the part? Just seems very strange to me that PP would tell me that the parts nor any overhaul was available and that a very well known (locally) overhaul facility also told me the parts were not available after searching for a couple of weeks.
 
Todd,

Yes, it's normal. Your efis is likely fed through the ebus diode, which creates a voltage drop. Once you turn on your ebus switch it sees bus voltage.

You can improve the voltage drop by using a Schottky diode on the ebus.

Lenny

Voltage drop from a typical diode is .3 - .4 volts (.1 - .2 on a shotkey). A full one volt drop points to something different. Also need to confirm where the diodes are before making this assumption.

Larry
 
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Larry,

That's under no load. Once you start applying some load it voltage drop increases to .4V+ on a Schottky. It can go up to 1.1V on a rectifier bridge.

See Figure 1. for the IXYS Schottky diode, and Figure 3 for the bridge rectifier.

The Schottky is used by Perihelion, and a similar bridge was recommended by Bob Nuckolls.


Lenny
 

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It's been answered once above, but I'll answer it again.

The ACS regulator part is indeed the same as original, modified with a wire for the OV protection and comes with brushes. It's a good idea to keep one on hand for a spare. I used my spare the last time I had a failure, which was caused by a worn bearing that broke one of the brushes.

The current B&C offerings use a very similar regulator module, but it also is hacked internally to jumper a couple of terminals together to basically just bypass the whole module. The module is only there because it acts as the connector and has the proper terminals to distribute the connections to the alternator in the necessary spots.

While I would recommend a Plane-Power user keep a modified OEM regulator/brush Assy on hand, I think with a little work it would be easy to figure out which off the shelf part would work in a pinch, if you were willing to give up OV protection to get you home when AOG for a bad regulator.

One other note: Alternator shops are familiar enough with these types of alternators that if you can find one willing to help you, they can rebuild them completely, other than that regulator hack. So if you find yourself stuck, see if you can find a shop that will help.
 
The regulator sold by Spruce is the same thing as the original. It's also a Hartzell part number. I replaced mine with one from Spruce. Looks exactly the same with the wire included. They give you the whole assembly with brushes and everything.

Lenny

Sorry for my lack of familiarity with how an alternator is assembled, but this should be an easy question:
Is the replacement of the regulator/brush assembly something that can fairly easily be done in the field? Could it be done on the airplane without removing the alternator from the airplane? (this would depend on whether the cover is held on with screws that are only accessible from the side that is against the engine, or by screws that go in from the back and nothing else on the engine is in the way (as if that EVER happens))
Does the back cover come off the housing to access the regulator/brush module, so if you can get the cover off, you can easily replace the regulator/brush module?
 
Steve,
I am not sure if you could replace them without removing the alternator or not. I would think that with all the right tools, maybe. That said, I think that since you'd already have the bottom cowl off, all there would be to do is pull the large bolt and the adjuster arm bolt and you'd have the alternator off. That would give you a much better look at what the internals look like, and it would probably take less time, in the end. But yes, the regulator and brush assembly is just under the back cover, so it's not hard to get to.
 
Steve,

The back cover is held on by 3 screws all pointing aft. On the RV-10 there's plenty of room to remove it, not sure about the 4 cylinder engines.
Replacing the regulator/brush assembly is doable but you'll need a mirror or a phone camera to see what you are doing, especially if you haven't seen the internals of the alternator before.

Tim has a bunch of photos on his site, referenced a few posts above.

Lenny

Sorry for my lack of familiarity with how an alternator is assembled, but this should be an easy question:
Is the replacement of the regulator/brush assembly something that can fairly easily be done in the field? Could it be done on the airplane without removing the alternator from the airplane? (this would depend on whether the cover is held on with screws that are only accessible from the side that is against the engine, or by screws that go in from the back and nothing else on the engine is in the way (as if that EVER happens))
Does the back cover come off the housing to access the regulator/brush module, so if you can get the cover off, you can easily replace the regulator/brush module?
 
The regulator sold by Spruce is the same thing as the original. It's also a Hartzell part number. I replaced mine with one from Spruce. Looks exactly the same with the wire included. They give you the whole assembly with brushes and everything.

Lenny

Photos of Hartzell P/N 11-1043 Plane Power Regulator, Aircraft Spruce P/N 07-17968 $80.75
 

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Dan,

I looked at the data sheets of various alternator control chips, aka voltage regulators. Lots of bells and whistles in a lot of them (like load response control, soft start, thermal protection), but I don't recall any of them having a crowbar overvoltage feature. They were overvoltage protected just not with a crowbar type circuit.

I opened up my original PlanePower regulator and they do have a Mosfet in there that's used to short out the field circuit (crowbar).

Because of the above I believe that PlanePower's regulator is a custom one to include the crowbar protection, it's just in an OEM case.

Attached a photo of the innards of a very similar looking Transpo regulator and the PlanePower (darker case).

Lenny

I suspect the YR6621 is merely a YR662 Toyota regulator clone with an added jumper wire. Apparently it is common worldwide, from a bunch of different sources.

https://www.ebay.com/itm/PREMIUM-NE...7060-11250-84-27060-11260-IN257-/221848016822
 

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I just talked to Plane Power. They confirmed that the regulator/brush assembly available via Aircraft Spruce DOES include the overvoltage protection. I am going to get one and repair the unit I have on the shelf for use as a spare. They did confirm that there is no repair/overhaul available through them.
 
"We uniquely modify each alternator..."

Sheesh. Talk about seeing how the sausage is made. Were the previous generation B&C alternators also internally hacked like that?

that is a great teardown report. does anyone have the original Nippon Denso alternator part number that the PP alternators use? I’d buy one of those and replace regulator with the PP regulator/brush assembly and pulley.
 
It looks a lot like the late-80's Honda Civic 60A, which even has CCW cooling fans as the PP has:

334-1718_Primary__ra_p.jpg
 
Because of the above I believe that PlanePower's regulator is a custom one to include the crowbar protection, it's just in an OEM case.

I'm an official EIB (Electronics Idiot Boy), so thanks for taking a look!

Do you think a YR662 or one of the many which cross reference would fly home in a pinch? Sure, no OV, but...
 
I think it would be fine in a pinch.

These regulators have a "failsafe" feature that monitors the B lead, so if the field gets disconnected they will keep going, so you really have no way of shutting them down. That's the main issue. It's mentioned on the datasheet of this regulator chip from ST. They all seem to have this "feature" though.

https://www.st.com/resource/en/datasheet/l9409.pdf

Lenny

I'm an official EIB (Electronics Idiot Boy), so thanks for taking a look!

Do you think a YR662 or one of the many which cross reference would fly home in a pinch? Sure, no OV, but...
 
Denso replacement?

Dan,

I think this is the correct ND replacement at 60amp. DENSO rebuild @ Summit Racing. Maybe I’ll buy it and the PP regulator and see if they’re a match?

“ 1988 HONDA CIVIC Denso Remanufactured Alternators 210-0229”

https://www.summitracing.com/parts/dnp-210-0229/year/1988/make/honda/model/civic

Stange, three concurrent electrical threads all intertwined.

https://vansairforce.com/community/showthread.php?t=185733

https://vansairforce.com/community/showthread.php?t=185508
 
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1200 Hr PP 60A Alt Failure - Options?

I think this is the correct ND replacement at 60amp. DENSO rebuild @ Summit Racing. Maybe I’ll buy it and the PP regulator and see if they’re a match?

“ 1988 HONDA CIVIC Denso Remanufactured Alternators 210-0229”

https://www.summitracing.com/parts/dnp-210-0229/year/1988/make/honda/model/civic


Hi Tim, curious whether you purchased these and what you found? If I read these prior posts correctly, I think you're saying that this alternator together with PP's modified VR/brush assy - when assembled - are fit form and functionally equivalent to PP's 60A alternator - maybe even better since this is a ND alternator whose components have better reliability than other aftermarket/clone options ?

I finally had my 60A PP alternator fail after 9 trouble-free yrs and 1200 hrs and I'm trying to figure out how to best address this - since PP doesn't service & I haven't found a smoking gun. (Alternator works fine for a few minutes then voltage decays and then the field breaker pops & the ALT-FAILED annunciator comes on). Brushes are fine, rotor shows 2.7 ohms, stator fields have no open circuits. Not sure that replacing the VR/Brush Assy or diode pack will fix my problem so not sure what to do.

My tension arm bracket P/N 99-1004 is also cracked so I'm looking for one of those if anyone has one for sale...
 
Hi Tim, curious whether you purchased these and what you found? If I read these prior posts correctly, I think you're saying that this alternator together with PP's modified VR/brush assy - when assembled - are fit form and functionally equivalent to PP's 60A alternator - maybe even better since this is a ND alternator whose components have better reliability than other aftermarket/clone options ?

I finally had my 60A PP alternator fail after 9 trouble-free yrs and 1200 hrs and I'm trying to figure out how to best address this - since PP doesn't service & I haven't found a smoking gun. (Alternator works fine for a few minutes then voltage decays and then the field breaker pops & the ALT-FAILED annunciator comes on). Brushes are fine, rotor shows 2.7 ohms, stator fields have no open circuits. Not sure that replacing the VR/Brush Assy or diode pack will fix my problem so not sure what to do.

My tension arm bracket P/N 99-1004 is also cracked so I'm looking for one of those if anyone has one for sale...

Don't jump to a conclusion about the looks of an alternator. ND tailors alternators specifically to meet OEM requirements. Note the SRE housing has a boss dedicated to the mount. The PP60A does not. They may both be a 100mm OD stator which is fundamental to the PP, but even the bearings can be different even when they look the same. I have a set of new bearings gathering dust to illustrate that comment.

If you have 1200 hrs, your lowest investment in labor, risk and $ is to either get a new PP or replace it with a B&C.

The only available universal part I found in the PP60A is the diode bridge. The regulator is special, the SRE housing is special, the SRE bearing is special. Only the regular and diode bridge can be trusted to be replaced. I have been down this rabbit hole.

re your failure: I made a crude test bench in about an hour. You can do that and test your alternator to see what is bad. Follow the test procedure for it to bypass the regulator, while measuring voltage. You may have a broken stator wire or bad diode bridge.
 
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Thanks Bill. Some good thoughts there.

I removed my diode pack and flipped it over. Here's what it looked like. Thoughts? The stator field wires all seemed intact, none broken there.

re your failure: I made a crude test bench in about an hour. You can do that and test your alternator to see what is bad. Follow the test procedure for it to bypass the regulator, while measuring voltage. You may have a broken stator wire or bad diode bridge.

Where did you find a test procedure for this alternator? I could not find one.
 

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Had similar experience

Thanks Bill. Some good thoughts there.

I removed my diode pack and flipped it over. Here's what it looked like. Thoughts? The stator field wires all seemed intact, none broken there.



Similar experience with the diode stack on my PP. Replaced with this - Restored and working fine.

Replacement Diode Stack
 
Seems like the B-lead post has been subject to vibration. Too much hanging wire?
Yes, it sure does look like it from the cracks in the rectifier, doesn't it? Curious, since my B-Lead was secured to the cover with a large zip tie about 2-3 inches from the B-Terminal so any vibration would be limited to a direction along the axis of the B-Lead.

Similar experience with the diode stack on my PP. Replaced with this - Restored and working fine. Replacement Diode Stack
Thanks!

My engine monitor records all parameters once per second but never recorded a voltage spike, yet my field breaker tripped. If there are voltage spikes, are they likely to be incredibly short duration events, so that the engine monitor is unlikely to catch them even at its fastest recording rate of 1/s? Or are there other VR failure modes (unrelated to overvoltage) that would cause the field breaker to trip? Would a cracked/intermittent rectifier lead to overvoltage & crowbar shutdown via field breaker trip?

Is there any documentation available regarding bench test procedures for these alternators? I couldn't find one on PP's website. I brought this to an auto parts store to test but they couldn't do it since their test setup requires a vehicle make & model, and the regulator is modified by PP so the electrical connections are altered. Maybe going to a real alternator shop instead of a parts store is the key?

My tension arm bracket is also cracked so I'm looking for one of those if anyone has one available...
 
Cracks...

Maybe not the "B" lead flopping around but an out of balance pulley, rotor or both - you can spin it up to a few thousand RPM and feel the vibration if that's the case.
 
Thanks Bill. Some good thoughts there.



Where did you find a test procedure for this alternator? I could not find one.

Can you post a picture of the bearing on the slip ring end of the rotor? This could be critical to your ability to complete the rebuild. This end bearing is a whole new subject in itself.

I tested a PP with a fried diode and the voltage was low and drawing high amps from the field to try and reach output voltage.

Look at the circuit diagram on page 6. Note that the rotor has one leg attached to the B lead (+12v). The PP has that connection as external i.e field wire. Now, Locate F and note that you can ground it to give the field full raw 12DCV power. That would drive up the voltage and let you know that the alternator can make power. The regulator controls the output voltage vis the ground side.

A moot point on the diode bridge now, as you really need one.

Here is the test procedure. Click and save as . . .

View attachment Toyota Alternator testing.pdf
 
Thanks for the test procedure and diagnostic info Bill, very helpful! I also found this video for troubleshooting and bench testing one of these alternators:
https://youtu.be/at_R7sENE0s

Incidentally testing my cracked rectifier showed that all diodes were good but since my problem is intermittent that shouldn't be too surprising that it seems fine. I'm hoping that replacing it will correct my issue.

Can you post a picture of the bearing on the slip ring end of the rotor?

I have not opened up the case to get a look at the bearings since mine feel fine but I'll snap a photo if I do.
 
2nd

It seems the common failure for these alternators is broken wires on the stator. May want to give a look inside before modifying the VR. Several posts on the subject.

Larry


Replaced a regulator board once when one of the three stator windings broke. Didn't fix it and didn't see the real problem until the 2nd wire broke as well killing all output
 
New rectifier assembly seems to have fixed my popping field breaker issue. Test flight today and all is well.
 
Replacement Stator P/N for 60A PP Alternator

Maybe this will help somebody out...

Turns out after 1225 hours I had some broken stator wires, common problem. That may or may not have led to a failed rectifier replaced this spring. If anybody is ever looking for a replacement stator for their Plane Power 60 Amp AL12-EI60B alternator, the part number to find is:

Denso 27-8209, 27-8200/340-52005

The stator is 36 slots, 100 mm OD, 77 mm ID, 25-26 mm long (laminated steel core). With the copper windings the length is 54 mm. ~15AWG wire (0.058 in dia).

Online prices range from $22- $50. Takes about an hour to swap out, a little fiddly but pretty straightforward.

Sources current as of this writing include:

https://www.amazon.com/dp/B07HFGR9PR/ref=cm_sw_r_apan_glt_fabc_1YYT90PTY1SK9T9K6XRJ

https://www.ebay.com/itm/New-Stator...2349624.m46890.l49286&mkrid=711-127632-2357-0

https://www.ebay.com/itm/Electrical...2349624.m46890.l49286&mkrid=711-127632-2357-0

https://issuu.com/arrowheadep/docs/componentscatalog/72

https://www.innovav.top/index.php?main_page=product_info&products_id=736338

I was unable to find the P/N for this stator despite hours of searching the forums, so hope this might help somebody out sometime. Good luck.
 
Field switch question

My Plane Power also failed this weekend after 830 hours of service. Happened away from base but for some reason I have packed my spare alternator for the trip. I did not have the time to do fault finding yet.

Slight thread drift - I have always started and then switched on the field switch in order for the alternator to start charging. Is there any evidence or data out there that might suggest that one should have the field switch on before starting?
 
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