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How to Repair a Plane Power 70 Amp Alternator

Jim Ellis

Well Known Member
My Plane Power 70-amp alternator died after only 89 hours of use. Of course, it is 4 years old so no warranty. When I tried to buy a replacement, I found that the current price for the AL12-EI70/B was over $700 plus a $200 core charge. Unfortunately, that includes the install kit which I don’t need. The alternator alone, Hartzell Part Number 99-1006-1, was nowhere to be found at the places I checked.

Well maybe I could repair the broken one if I could find the parts. Aircraft Spruce has a long list of Hartzell (Plane Power) parts but when I contacted Spruce, they told me that none of the parts listed were for my alternator. Only a new replacement unit was available.

I did a long search of the internet and finally found a (Nippon)Denso “First Time Fit” Starter and Alternator Catalog that listed all their alternator variants along with pictures. After matching the plug style and the amperage output along with a photo, I determined that my Plane Power 70-amp alternator started out life as a Denso Part Number 210-0213 (Lester # 13509). (Bottom of Page 335)
IM6h2Skm.jpg


Now I began a search for repair parts and quickly found parts for 1992-95 Honda Civic and 1993-95 Honda Civic del Sol. I found part numbers and sources for replacement bearings, regulators, brush holders, rectifiers, stator field windings and other miscellaneous parts.

The aftermarket replacement internal voltage regulator does not have the built-in overvoltage protection that comes with the Plane Power brand alternator. I didn’t need this in my case since my Vertical Power VP-X Sport already provides overvoltage protection. If you do install a replacement regulator and want overvoltage protection you can add something like a Perihelion overvoltage protection device.

After removing the rear cover, I pulled the brush holder, the regulator and the rectifier plate.
XED7LUpl.jpg


To my surprise I found three of the four wires connecting the stator field to the rectifier plate were broken off at the base of the terminals.
acMpC6dl.jpg


The breaks may have been from overheating or vibration or both. I replaced the damaged stator field winding with a new unit and reassembled the case with all new parts.

It took me thirty minutes to install the new parts and return to a fully working alternator. The total cost of all the replacement parts was $98.00. The cost of parts that I probably didn’t really need was $50.00, but I ended up with a completely new rebuilt alternator (except for new bearings). If you want to see someone else’s video showing how to install the parts I replaced click here.

If you are not inclined to repair your Plane Power alternator you could just buy a rebuilt Denso 210-0213 alternator for around $150.00 plus a $30-35 core charge. You would need to swap the drive pulley from the P-P alternator to the new rebuilt alternator with an impact wrench. (85 foot/pounds)

It is not my intention to be critical Hartzell or Plane Power. They are nice folks and their business model is what it is. My only goal here is to provide some other possible options when, as it will, your P-P alternator dies an untimely death.
 
Thanks for posting this. Quite educational. Is that the same Alternator Van’s sells ?

https://shop.vansaircraft.com/cgi-b...390-399&browse=engines&product=alternator-kit

That’s listed as 60 Amp and you mentioned 70 Amp.

When mine broke I just ended up buying a new kit from Van’s as it was the fastest/cheapest option (cheaper then having Plane and Power just sell me a new alternator alone even with core credit...) but wanted to fix the broken one that is sitting on my bench for a while now so I got a spare.... .

Thx

Oliver
 
Not The Same

The 60 amp and the 70 amp models are not the same. Use the Denso Catalog link and match the plug, amps, and picture to find the 60 amp version.
 
Thanks for posting this. I saved a copy of the catalog for possible future reference. :cool:
 
Great post Jim!

Question: How far did you have to hear the alternator down to get to those wires?

Maybe it would be possible to put some silicone or other vibration damping material on them to reduce the likelihood of failure.
 
Broken wire...

My 60A Plane Power alternator, AL-12EI60 began to throw the "ALT" light after only ~75 hours. Not knowing any better, I bought a new unit. I decided to overhaul the failed unit. During the course of disassembly, I found that one of the 4 wires from the stator assembly to the diode pack had fractured and was making an intermittent connection.

I wonder if they had a bad lot of these, circa 2015...
 
Removing Stator Field Wiring

Great post Jim!

Question: How far did you have to hear the alternator down to get to those wires?

Maybe it would be possible to put some silicone or other vibration damping material on them to reduce the likelihood of failure.

You have to separate the case half's but easy to do. The stator field coil just pops right out.
 
That's how one of my 60 Amp PP's failed. There was enough wire left to solder on an extension. It is now flying as a temporary replacement for another PP failure in a buddy's plane.

As you found, the guts are pretty generic and inexpensive to replace if you can track down the right part numbers. We need a PlanePower repair page / Wiki on VAF!
 
Rebuilder

You might look around for an alternator/starter shop that can do a rebuild for you when it comes time. The ones I've worked with are old school guys who can do all the bearings/brushes/wiring RR for a reasonable charge.

If you're in the NW, Whatcom Electric & Battery is a good example. :)
 
Alternator

Ft. Worth starter and generator will overhaul these units cheap. I used them for years when I lived in the area.
 
I just had my PP alt repaired at a local shop for $200. Next one will be $59.95.
I had a Nippon in my plane for 18 years and thought I would upgrade to an airplane alternator, that didn't work out. The extra $600 or so difference buys a lot of avgas.
 
Bob,
Is this a 60 or 70 amp alternator? Does not say in description. Is the plug in the back the same as the PP 60 amp alternator?
Thanks.
Johan

Its a 35A unit that will put out 60A according to the test sheets. Even the most fully equipped airplanes today with LED lighting will barely require 20A.
 
The 60 amp and the 70 amp models are not the same. Use the Denso Catalog link and match the plug, amps, and picture to find the 60 amp version.

Good write up Jim, I have a couple of questions before the trail goes cold.

1. Is the stator held in place with a shoulder bolt like this? If it did not have this retention method, that could have been the issue. Also assembly of the screws can stretch that wire, but it needs a little bow to prevent failure. I think you had a defective assembly.
IMG_4659.jpg

2. Did your slip ring bearing look like this one with the plastic rings on it?
IMG_4764.jpg
3. Did you check the ID of the stator of the OD of the rotor? I want to determine if the 70 amp is a larger size than the 60 amp. The 60A is 100mm stator OD, the next Denso size up is 118mm. What was yours?
 
Its a 35A unit that will put out 60A according to the test sheets. Even the most fully equipped airplanes today with LED lighting will barely require 20A.

Except for those of us flying the EFII or SDS units.
 
Its a 35A unit that will put out 60A according to the test sheets. Even the most fully equipped airplanes today with LED lighting will barely require 20A.

I used the 60 amp B&C alternator and wish I had used the 40a version.
I rarely use more than 10a unless making up the loss from the start-up.
 
Good write up Jim, I have a couple of questions before the trail goes cold.

1. Is the stator held in place with a shoulder bolt like this? If it did not have this retention method, that could have been the issue. Also assembly of the screws can stretch that wire, but it needs a little bow to prevent failure. I think you had a defective assembly.
View attachment 5524
2. Did your slip ring bearing look like this one with the plastic rings on it?
View attachment 5525
3. Did you check the ID of the stator of the OD of the rotor? I want to determine if the 70 amp is a larger size than the 60 amp. The 60A is 100mm stator OD, the next Denso size up is 118mm. What was yours?

1. Yes, the shoulder on the through bolts hold the stator field in place.

2. I saw nothing like the slip ring bearing with plastic rings you show.

3.The stator ring I replaced had an OD of 118mm.
 
Amazed

That such a intelligent group keeps buying what seems to be an inferior product. Buy B&C .... 28 years and going strong on my 6A, 100hrs plus a year ...40 amp, small and light.
 
That such a intelligent group keeps buying what seems to be an inferior product. Buy B&C .... 28 years and going strong on my 6A, 100hrs plus a year ...40 amp, small and light.

I dunno, I *feel* that the evidence of inferiority is petty anecdotal. I bought my plane 5½ years ago and it's equipped with a PP 70 amp alternator. It never quit making power but it would occasionally trip the field breaker when I would turn an electrical item off. I think this was due to a problem with the crowbar over-voltage protection.

Because of this I bought a new PP and have never had a problem. The old alternator Still works, and I even loaned to to a AOG pilot in an RV7 that had electrical problems in SoCal. He flew it back to the Seattle area with no problems.

I have it back in my hangar as a back-up or loaner or whatever. I've put over 500 hours/year on my plane and can honestly say that I haven't had an PP alternator *failure*.

One thing about the internet is that you are more likely to hear stories of dissatisfaction than stories of things that work as they should. YMMV

-Marc
 
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