928drvr86.5

A wheatstone bridge is used for highly accurate engineering/testing purposes and utilizes resistors not diodes.

macreel

Wheatstone's bridge originated as a 'quadrilateral' arrangement of resistances
with source and 'detector'

and quickly became generalized in a number of impedance schemes under other
bridge names (Kelvin, Owens, Robinson, deSauty,....) with various sources and
detectors, including, today, active components.

Wheatstone's basic concept underlies a great deal of modern metrology.

(And provided me a pretty good career. God bless him. Amen).

G'luck all.

928drvr86.5

What career were/are you in that provided for the use of wheatstone bridges? I work for the John Deere Proving grounds testing construction equipement.

macreel

Ben B... For ~35 yrs I worked & managed Boeing Commercial
A/plane laboratories Instrumentation(Aerodynamics{wind tunnels],
Noise, Propulsion, Structures, Mechanical, Optics, Flight Test, etc )
in Seattle area and round the country/overseas.

Aerospace work came our way, too.

Astounding variety, ordinary and critical items/systems, super folks.

One of our 6x6 Supersonic tunnels was donated to Iowa state, in
Ames, Iowa, i.e., farm country. After they got it re-assembled the
student (slave labor) painted it Yellow and Green - John Deere colors !!

G'luck.

the flyin' scotsman

Really, well I know its many years since I was in school but I believe the rectification circuit that consists of 4 diodes is know as a 'bridge' rectifier after the design of the wheatstone bridge.

928drvr86.5

Cool!!! I am treading a somewhat similar path. I would say that at least 50% of my time is spent on stress analysis instrumentation on structures I.E. torsion, bending, Tension/Compression bridges. The rest is split between hydraulic, noise&vibration, and electrical load testing.

the flyin' scotsman

Not sure if thats directed at me but Telecommunication Engineering...........specificaly the design and operation of digital switching that progressed to wireless technology for cellular networks with a small Canadian company Nortel Networks.

macreel

Malcolm... you got it. Discrete or integrated, that's the crux of a full-wave
'bridge' power supply, in power or instrument applications. Some diodes
are tiny, some are honking huge.

Good memory.

928drvr86.5

Don't worry, the bridge configurations have not changed in that time, you're not that old

the flyin' scotsman

Thanks Macreel..............good to know the brain still functions somewhat. You on the Leavenworth run? If so say hi to all.

Lorenfb

"Since mine is a '79, do you have any information about the alternater in mine?"

The early 928s, '78-'81, used the Marchal 85 amp alt. This used press-fit diodes into aluminum
plates. This alt was more reliable than the Paris-Rhones ('82-'83 & early replacements). Its problem
was poor diode mechanical connections if the alt was overheated via excessive currents,
e.g. very low/bad battery.

As with most 928 voltage gauges, the needle needs to be positioned to the true voltage when
running with the basic/average number of accessories being used to have an idea of the actual
voltage. A better solution is modify the instrument cluster to re-connect the alt sampling
voltage to the alt's field voltage (basically the alt output voltage) versus the present sampling
point which is affected by basically ALL loads which are switched on/off making for an unrealistic
or unuseable voltage gauge.

macreel

Malcolm... sorry the weather defeated you. Yes, we had/are having a good run.
Check the pNW:Leavenworth .... thread for 3 pics. I had to bail
at Leavenworth. They're still there or in Wenatchee. I believe dinner
is to be at some 'bierstube'/gasthof in L'worth.

Great run.

928drvr86.5

Nortel was hiring alot of People from my Army unit in the mid 90's as they transitioned into the civilian world. I was looking at a career with Nortel but ended up at John Deere (hometown). I was in the Communications and Electronics Engineering Command at Ft. Huachuca Az. , and i was an Air Traffic control Systems Tech for some time before that.

It's funny how things and people inter-relate, I learned at the Denver 928OCIC that Louie Ott was a radar technician for many years as well.

the flyin' scotsman

Small world eh? No wonder we make up such a great diverse group.

I drive a Universal on the home 40 acres..........no offence.

Back on topic; can't the most modern 928 alternator fit on the '79?

928drvr86.5

I guess it mostly depends on differences in mounting.