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Generator voltage regulator

Barton

PATRON
Longview, TX
My 1952 PA-18 has an O-290D2 installed which still has the original type A generator and voltage regulator. I’ve diagnosed the generator and found it to be working, I have continuity between the generator and the regulator and I have battery voltage at the regulator. I suspect the regulator is toast. The regulator on it is and ELECTRODELTA VR-300-14-20 The generator is a Delco Remy 1101891 20A. Can anyone confirm this is the correct regulator. Spruce sells one of the same number which is related to Generator numbers 1118736,1118904,1119226 so none are the same as mine although they all seem to be 20A output. Spruce also has a VR200A which relates to Piper 484121 but I can’t find out what the number is related to. Any help greatly appreciated.
 
The Piper number for the reg on a 20 generator is 450-383. That crosses to Zeftronics number G1200N. That, in turn, crosses to ElectroDelta number VR300-14-20. I can't find a reference to a reg for generator 1101891 but the above numbers are for a 14 volt, 20 amp generator.

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The North American Pilot Association, (NAPA), can cross reference those numbers for you and save you some money. Also univair has a large supply of N.O.S. Delco stock not very well inventoried that may include that regulator. On my factory tour when I picked up my new fuselage they encouraged me to call and they'd run in the back and take a look.
 
Agreed, although as an A&P I prefer the name, Northern Aircraft Parts Administration. Just make sure that the reg you chose is for a 12 volt system (set to around 14 volts) and limits the current flow to 20 amps as per your generator.

Also, you might want to look at Plane-Power kit number SAL12-70.

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Ah agreed, I did put the plane power on my 12 project, I love it but a very expense way to save 1# over my old generator and tractor regulator that never gave me any problems.
 
Ah agreed, I did put the plane power on my 12 project, I love it but a very expense way to save 1# over my old generator and tractor regulator that never gave me any problems.

That’s kind of my attitude too. Id rather spend the AMU’s on LED lights than on an alternator to run the old incandescent bulbs. I don’t fly at nite much anymore anyway. Thanks for the help. I hadn’t thought about calling Univair but thats a good idea, NAPA is a great idea!
 
Think I still have generator someone removed at engine o/h going to a alternator. Haven’t been able to give it away. Don’t think I put it in the trash... yet. Maybe...


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Ok guys thanks for all the help. I took the cover off the regulator and it looked perfect inside, clean and no evidence of arcing. It didn’t have a grounding strap from the regulator case to the airframe so I made one. I ran the engine with the regulator off and tested the generator output thru the leads to the regulator rather than thru jumpers as I did before and got the same result. From that I deduce that the generator is working and the leads to the regulator are good. Reinstalled the regulator and started it up and for the first time I got an indication from the amp meter that something is talking to it but it was twitchy and on the negative side. Something I read last night mentioned that symptom and said it related to field polarity and something else said the polarize the field by momentarily touching the BAT connection on the regulator to the FLD connection. Did that and started it again and it worked. I showed a positive charge of 5A at 1400RPM and when I put the landing light load on it the generator picked up the load. I have my fingers crossed that its right again and the problem was no ground from the regulator to the airframe and lost field polarity from all the messing with it.
 
Actually, the term "flashing the field" is misleading.
To polarize the generator, you touch a jumper between the battery & generator (not field) terminals on the regulator.
Easy way to remember for me is from back in my Harley days--
12v system with a Bosch regulator-- touch b+ (battery) to D+ (armature).
DF (field) terminal isn't involved.
This is done with everything connected, but before starting engine.
From my old Harley shop manual:
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This is from the Piper manual. Just remember that 'flashing the field' is done to restore magnetism in the field shoes of the generator. And this is only necessary when the generator has sat so long that the existing magnetism has declined to the point that the generator will not produce power or after improper maintenance practices.

AND. 'Flashing the field' has produced many, many fried regs and generators. Use caution.

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My C180 manual has similar instructions.
Just didn't have it here at home, so used the old HD manual.
Question: if jumping between bat & gen terminals at regulator correctly polarizes the generator,
does touching between the bat & field terminals incorrectly polarize it--
as in "...reverse polarity causes vibration, arcing, and burning of the relay points"?
 
During flashing, the current needs to pass through the circuit in one specific direction. This will put the 'north pole' and 'south pole' of your magnets in the correct orientation. If you pass the current in the wrong direction during the flashing, the poles will be reversed and will produce reverse polarity current flow. So the best bet is to just follow the book.

But I'd have to sit down and do my home work do give you a definitive answer to your question.

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yes, flashing the field re-magnetizes the field shoes, which are the steel part that the copper field coil winding's are wound around. thats where the "residual magnetism" resides, thats what initiates the build up of the generator voltage so it can put itself on line. without it, no output reaches the system. in a type A circuit, the Arm terminal goes to the + brush, which is also the beginning of the field circuit. so, putting battery + on the Arm terminal also puts current through the field in the normal direction, and restores residual. thats the key... current in the coil in the normal direction. in an A circuit, the negative side of the field is made through the regulator. note that unless you lift a brush, the generator will try to motor. on the other hand, you only need to scratch the jumper on there long enough to spark. on small gens, no matter but anything around 50A or more you really should lift a brush. it is also best to ground the F terminal for this process which takes the regulator and wires out of the equation. when testing (at the generator terminals), loss of residual magnetism will make the generator read either zero or possibly a small negative voltage. normal residual is about .5 to maybe 2.5 volts on a small gen. if you have that, the field can be tested by jumping F to ground and running the engine up. voltage should follow the RPM and you will overvolt somewhere above 1/4 -1/2 throttle. if so, and there is no output, the gen is good and the regulator and wires are suspect

B circuit is the same but polarities reverse... long story. I used to teach a class on this stuff. I wrote a thing on how to troubleshoot generator/alternators. I'll see if I can find it if you want
 
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Hi....The force you get from the utility is from a middle tapped transformer. The middle tap is grounded and called impartial. You can do likewise, as long as its 120 to focus on the two sides and 240 across the lines. In single stage boards, the heap is offset with the 120 volt loads as the 240 burdens are allways adjusted. As thermite said, what you need is limit. Indeed, even matrix associated frameworks have voltage changes, once in a while alot. Relies upon the fact that you are so near the transformer on the post, and how over-burden the framework as of now is. Where I reside in Nicaragua, you are fortunate to get 106 or 108 volts from hot to impartial.
 
Hi....The force you get from the utility is from a middle tapped transformer. The middle tap is grounded and called impartial. You can do likewise, as long as its 120 to focus on the two sides and 240 across the lines. In single stage boards, the heap is offset with the 120 volt loads as the 240 burdens are allways adjusted. As thermite said, what you need is limit. Indeed, even matrix associated frameworks have voltage changes, once in a while alot. Relies upon the fact that you are so near the transformer on the post, and how over-burden the framework as of now is. Where I reside in Nicaragua, you are fortunate to get 106 or 108 volts from hot to impartial.

Hi JethTran
You are referring to AC power transformers. On small aircraft, we are using engine driven DC generators and alternators. The power produced by these units is typically used at the the rated voltage and not stepped up or down.

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