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Externally regulated AUTO Alternator

pecanflyboy

Well Known Member
There is a ton of information and opinions about which auto alternators are best and whether to use an internal or external voltage regulator. I've come to the conclusion that I want a 50+amp auto alternator, without internal regulation. I'm using an external voltage regulator.

Within those parameters, I'd like Lester numbers or Autozone numbers for alternators that fit the description. These alternators should have a Field post and a B+ output post.

I'm having a difficult time finding an alternator without an internal regulator, and I don't want to modify it for an external voltage regulator.

Thanks in advance.
 
Well, that was fun. I literally looked at all the alternator pictures on Autozone, trying to find the smallest, CW rotation, externally regulated unit available. What I've discovered is that if you want small with internal fan, it's going to have an internal regulator.

The 14824 is the most compact unit delivering 55amps, internal fan, with a CW rotation. The stator has only 100mm diameter. I has a 3 pin plug with an internal regulator.

I actually have one of these in hand. I guess I'm going to have to figure out how to remove the internal regulator.
 
I have used the 14158 on both my planes with good success. Correct rotation, 50 amps and externally regulated. Pulley size is optimized for the smaller lycoming flywheels, but RPMs should still be within range for larger pulley flywheels. If you cross match the ND number, you will find a unit remanufactured by ND for about $70 at summit racing or rock auto. That should provide greater reliability than the general aftermarket.

Larry
 
I have used the 14158 on both my planes with good success. Correct rotation, 50 amps and externally regulated. Pulley size is optimized for the smaller lycoming flywheels, but RPMs should still be within range for larger pulley flywheels. If you cross match the ND number, you will find a unit remanufactured by ND for about $70 at summit racing or rock auto. That should provide greater reliability than the general aftermarket.

Larry

Thanks Larry,
I've looked at that one. You have to be careful to get the correct fan, as I've seen the 14158 with fans in both directions. Trying to run it down on Summit.

JC
 
Thanks Larry,
I've looked at that one. You have to be careful to get the correct fan, as I've seen the 14158 with fans in both directions. Trying to run it down on Summit.

JC

Yes. However, I installed the one with the wrong fan on my 6. 650 hours of trouble free service, so suspect that it is not critical. I am confident the ND reman will have the correct fan.

Larry
 
Thanks Larry,
I've looked at that one. You have to be careful to get the correct fan, as I've seen the 14158 with fans in both directions. Trying to run it down on Summit.

JC

The alternator doesn't care electrically which way it rotates and it is doubtful the presence of the correct fan or even a fan at all is a big deal in our application. The 35a alternator Vans sold for years was delivered without a fan and overheating wasn't a problem. Many of us back in the day installed a blast tube aimed at the rear of the alternator.
 
pecanflyboy - I wrote an article for Kitplanes magazine early last year that explains how to modify the alternator for external regulation. You might check the article out and see if you wish to take on the task of modifying the alternator.
 
The alternator doesn't care electrically which way it rotates and it is doubtful the presence of the correct fan or even a fan at all is a big deal in our application. The 35a alternator Vans sold for years was delivered without a fan and overheating wasn't a problem. Many of us back in the day installed a blast tube aimed at the rear of the alternator.

Agree with Sam's comment here. I have no fan, with a blast tube to a molded composite shroud around the rear of the alternator.
 
I assume you want OV protection, that is the reason for external regulation. What I did was to add a contactor (80amp) in the alternator B-Lead. The contactor is normally open and powered directly from what would be the field breaker. I have a crowbar OV module connected to that breaker. In the event of a OV condition, the crowbar grounds, breaker trips, b-lead is disconnected from the buss.

There were two reasons I went with an auto alternator:
1) cost
2) field service availability

If you have to modify the alternator to make it work, then you loose one of the main advantages, unless you bring a soldering iron with you.

With the contactor solution, you get to keep both advantages and have OV protection. I can swap alternators with no modifications.
 
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Hmmm. This is the age of 3D printing. Sure seems like some enterprising person could design and print brush holders to replace the VR/brush module in ND alternators.....
 
pecanflyboy - I wrote an article for Kitplanes magazine early last year that explains how to modify the alternator for external regulation. You might check the article out and see if you wish to take on the task of modifying the alternator.

I've read both the Kitplanes articles. Thank you!:

https://www.kitplanes.com/alternator-mods-without-major-surgery/

Once I decided to modify my internally regulated 14824, I used the method described in the article below:

https://www.kitplanes.com/rewiring-a-nippondenso-alternator/

This technique turns all of the alternator terminals into the Field input from the external voltage regulator, and removes the internal voltage regulator. The pictures could be a lot better.

The goal is to route the Field to the aft/top brush, and ground the fwd/bottom brush. You remove the guts of the internal VR, and jumper the plug terminal pins to the aft/top brush pin.

The fwd/bottom brush is removed, and an insulated hole drilled in the back of the brush holder. You then install a new brush with a long lead. The lead from this brush is routed through the hole and to a grounding point on the alternator (or to the VR if you like). The grounding point on the alternator is located under one of the long screws that secures the rear cover.........do not take it to the B post!

The only part you need to purchase is a new brush with a long lead. I found these at O'Reilly Auto Parts as Part# 32-0123. I called in the morning and they had the parts in the store by early afternoon.

The article doesn't explain the details of what you are doing. I suggest that you use a voltmeter to understand the process and check continuity along the way.

If you need to change the alternator in the field, you go get your lifetime free replacement at the auto parts store, and then use a screw driver to swap the VR board and the brush holder. 5 minute job with no soldering.
 
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I assume you want OV protection, that is the reason for external regulation. What I did was to add a contactor (80amp) in the alternator B-Lead. The contactor is normally open and powered director from what would be the field breaker. I have a crowbar OV module connected to that breaker. In the event of a OV condition, the crowbar grounds, breaker trip, b-lead is disconnected from the buss.

There were two reasons I went with an auto alternator:
1) cost
2) field service availability

If you have to modify the alternator to make it work, then you loose one of the main advantages, unless you bring a soldering iron with you.

With the contactor solution, you get to keep both advantages and have OV protection. I can swap alternators with no modifications.

Once you make the modifications, you only need a screw driver to transfer the modification to a replacement alternator. You swap the VR and the brush holder, and you are done.
 
I've read both the Kitplanes articles. Thank you!:

https://www.kitplanes.com/alternator-mods-without-major-surgery/

Once I decided to modify my internally regulated 14824, I used the method described in the article below:

https://www.kitplanes.com/rewiring-a-nippondenso-alternator/

This technique turns all of the alternator terminals into the Field input from the external voltage regulator, and removes the internal voltage regulator. The pictures could be a lot better.

The goal is to route the Field to the aft/top brush, and ground the fwd/bottom brush. You remove the guts of the internal VR, and jumper the plug terminal pins to the aft/top brush pin.

The fwd/bottom brush is removed, and an insulated hole drilled in the back of the brush holder. You then install a new brush with a long lead. The lead from this brush is routed through the hole and to a grounding point on the alternator (or to the VR if you like). The grounding point on the alternator is located under one of the long screws that secures the rear cover.........do not take it to the B post!

The only part you need to purchase is a new brush with a long lead. I found these at O'Reilly Auto Parts as Part# 32-0123. I called in the morning and they had the parts in the store by early afternoon.

The article doesn't explain the details of what you are doing. I suggest that you use a voltmeter to understand the process and check continuity along the way.

If you need to change the alternator in the field, you go get your lifetime free replacement at the auto parts store, and then use a screw driver to swap the VR board and the brush holder. 5 minute job with no soldering.

So I just finished up the mod to my ND internal regulated supplied by Vans, but I took a slightly different approach...I only accomplished part of the mod (turning the IG terminal into the sole F (field) supply) and left the alternator internally regulated. Here's why I went this route...

  1. My main concern was OV protection and the ability to positively turn off the field
  2. I didn't want modifications outside of the alternator...this would allow me to locally source an alternator which would be plug-in-play
  3. With proper blast cooling I can mitigate failures of the regulator and rectifier.
  4. The ability to do this with materials I already had...I only needed to purchase a 50 cent diode but I also replaced the brushes for $10 while I had things apart.
  5. I didn't see the need to have an external regulator, nor have a contactor for the B+ output.

I followed the instructions from AeroConnection here:
http://www.aeroelectric.com/articles/Nipon-Denso_Alternator_Mod.pdf

The directions are pretty good and go into explaining why one should make this mod. I only deviated from the directions in that I used my already installed alternator and B&C OV module.

Just reinstalled this afternoon to test, and putting out precisely 14.2V under various loads with positive control from the ALT switch and field breaker. I now feel a little better about dispatching in hard IMC in my all-electric airplane.
 
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Nice article. Better photos, for sure! There are a dozen ways to go about installing and auto alternator, and it's good to share the variations. Each fits our own particular needs. For me, I already have a B&C external VR, so I went this route:

1. I gutted the ND voltage regulator, made the 3 pin plug all field input, connected the bottom/forward brush to ground. Now the alternator is completely controlled by my external VR. I can go to the auto store, swap alternators, and swap the gutted VR and brush holder in 5 minutes, and I'm done.

2. MOUNTING! The distance between the mounting ears on the bracket should be around 2 5/8" with a smaller diameter bolt than the Lycoming alternators. You can either fabricate your own, or find one to buy. The Plane Power boss bracket did not work as the ears were too wide (I could have used washers), bolt diameter too large, and the position wrong. However, the Vans "Bracket kit for generic Nippon Denso Alt" was spot on...go figure. ES ALTERNATOR BKT KIT It's a machined aluminum bracket and tension arm that is very light, fits the alternator perfectly, and positions it correctly. It uses four mounting bolts on the Lycoming boss mounts. Plug and play, and I'm very happy with it.

Jimmy
 
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Nice article. Better photos, for sure! There are a dozen ways to go about installing and auto alternator, and it's good to share the variations. Each fits our own particular needs. For me, I already have a B&C external VR, so I went this route:

I think this is a more reliable setup for sure. If I end up changing the alternator in the dead of winter, on the ramp in B-F-E, it will probably motivate me to switch to an external regulator.
 
So I just finished up the mod to my ND internal regulated supplied by Vans, but I took a slightly different approach...I only accomplished part of the mod (turning the IG terminal into the sole F (field) supply) and left the alternator internally regulated. Here's why I went this route...

  1. My main concern was OV protection and the ability to positively turn off the field
  2. I didn't want modifications outside of the alternator...this would allow me to locally source an alternator which would be plug-in-play
  3. With proper blast cooling I can mitigate failures of the regulator and rectifier.
  4. The ability to do this with materials I already had...I only needed to purchase a 50 cent diode but I also replaced the brushes for $10 while I had things apart.
  5. I didn't see the need to have an external regulator, nor have a contactor for the B+ output.

I followed the instructions from AeroConnection here:
http://www.aeroelectric.com/articles/Nipon-Denso_Alternator_Mod.pdf

The directions are pretty good and go into explaining why one should make this mod. I only deviated from the directions in that I used my already installed alternator and B&C OV module.

Just reinstalled this afternoon to test, and putting out precisely 14.2V under various loads with positive control from the ALT switch and field breaker. I now feel a little better about dispatching in hard IMC in my all-electric airplane.

I wrote those instructions 12 years ago after I performed that mod on my own alternator (and then sent to Bob, who published it). That same alternator is still performing well after 800+ hours. One of these days, I'll buy another alternator and do a better job of step-by-step photos.

Cool thing about this mod is you can do it to a spare regulator and brush holder and keep that in the airplane for field repair. You don't even have to remove the alternator from the airplane to change out those parts.
 
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