Seeking Description of 14 & 28 VDC Gen Aviation Aircraft Power Supply Charatersicics 1

[kontiki99]

All,

I'm trying to understand typical voltage stability, noise and "spike voltage" characteristics typically found on GA aircraft 14V and 28V engine driven rectified alternator power systems.

Maybe the characteristics of an old 1940s automobile would do?

I'm looking into suitability of DO-160 testing and the basis for aircraft owner concerns about voltage spikes and the need for avionics bus master switches.

Thanks

My posts reflect my personal views and are not in any way endorsed or approved by any organization I'm professionally affiliated with.

 

[MOHR1951]

The text we used at Park's in the 60's and early 70's,may be of interest to you.It's title is; Aerospace Propulsion Powerplants,written by Cargnino and Karvinen.It was the text we used for all the AME electical systems classes,the title is misleading in takes it all in.It's dated ,but may be exactly what you want,hope it helps,may be check Amazon.com.sure its been out of print for awhile,last copyright 1967 by a group called Educational Publishers,1525 N. State St.,Chi town,USA.Good Luck.

 

[Comcokid]

Since you've mentioned General Aviation and Alternators, you might have specific applications in mind. You might find a more specific voltage spike definition in SAE J1113/11. The DO-160 specs cover a WIDE variety of power systems as found in aircraft without necessarily correlating the power system type to the specific spikes and pulses. The alternators used in the GA piston engine market are basically automotive types built with more reliable components and more paperwork. GA 14V and 28V are basically the same as automotive 12V and 24V systems with smaller battery capacity to save weight.

 

[IRstuff]

It's possible that 28V aircraft power will conform to MIL-STD-704

TTFN
I can do absolutely anything. I'm an expert!
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[GrandpaDave]

MOHR1951... Cargnino! That's a name I haven't heard in a long time.
He was one of my professor at Purdue in the early 60s.
There was another professor in Propulsion Engineering by the name of
Joe Liston who the students called Piston Joe. He had 100s of graphs,
nomographs... Oh, Prof Elmer Bruhn was still teaching there in 1961.

Were you a 1951 graduated at Parks? About 50 aeros in my
class and 95% went to St. Louis to McDonnell Aircraft. I still have my
original copies on MAC 338 and Mac 339.

G-pa Dave

 

[dgapilot]

Mohr1951,
We used the same book (Aerospace Propulsion Powerplants)in the late '70s at Parks also. Years later when I was teaching Powerplants at Fairmont State, I used it to supplement the text they made us use then.

While most current production GA airplanes are using alternators based on automotive designs, there are still a great many airplanes that were built in the 30s, 40s, 50s and early 60s that still use generators with vibrator voltage regulators. Not so prevalent, but still in service are generator systems with carbon pile regulators.

 

[MOHR1951]

Yes,G-pa Dave Purue had a great faculty,noted people with the degrees and also the industry exoerience.Today these two items don't seem to be important together.But they are and anybody in the real world knows and understands that,thus I and the aerospace community have a great deal of respect for Purdue University.Parks and Purdue seemed to have had a commom bond and goals back in those early times.Thus the texts and professors were all closely related.My days at Park's were in the late 60's and early 70's.Many of the texts we used then were the products of Purdue,a mutual admiration society existed between the two.
The Cargnino text was the best around,and I still pull it out to read about such obscure things as carbon pile regulators,it's fun,yeah I know that sounds crazy to most,but for me it beats anything X-Box has to offer,so when I run into people like you G-pa dave and dgapilot it makes it all worth while,we share a common bond.And like it or not all these high tech, people here talk of came from us back then,using our slip sticks and trig tables,my times have changed,and for the best I hope.

 

[GrandpaDave]

Thanks... "Those were the days my friend". Yep, I still have my CRC tables
that my mom bought me in 1958 and Peery's 1950 edition of Aircraft Structures.

 

[MOHR1951]

Grandpa Dave,Lost my Chemical Rubber Company handbook somewhere along the way,somebody got a real bargain if they are able to decipher my notes along the margins.
I replaced my lost copy of Perry with a paperback copy that's being republished by Dover,interesting to note that they brought it back into publication after all this time,somebody must be doing something right,and it shows that with all this high technology we have,often a person needs to get back to the basics before pretending to jump into the good stuff,a real reality check if you will.The addition of Perry is the first one not the second one he wrote in conjunction with J.J.Azar,which should never have even been published by McGraw-Hill,or at least proofread to weed out the first set of errors,anyhow I have both,and refer to them often,hand calculation methods are not a dead art,but a much needed refresher of statics and strength of materials.