In this google reference... one can count the four diodes needed for something to be called a full wave bridge rectifier...
I supposed more could be added... but a diode is only a one way valve...and it only takes four of them to deal with an ac sine wave to make it dc.. ..... unless placed backwards and used as a clipper of overvoltage (spikes typically)....

https://www.google.com/search?q=full+wave+rectifier&biw=911&bih=438&tbm=isch&tbo=u&source=univ&sa=X&ei=y2ytVOabJcSzggTWtYGADw&sqi=2&ved=0CB0QsAQ

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

In 120VAC applications to get full wave rectification you use four diodes as you aware. Two for the positive and two for the negative aspects of the AC wave.

Car alternators contain three-phases of AC that get rectified to DC so you need an extra 2 to take care of the 3rd phase.

(I believe)

http://en.wikipedia.org/wiki/Rectifier#Three-phase_bridge_rectifier

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Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
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93 300E 195k

Center tapped AC transformers need 2 diodes for full wave rectification, non center tap need 4 diodes. I think the alternator is wired more like a center tapped transformer, 2 diodes for full wave on ea of the 3 phases.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

That sounds right. Its been a while since I've looked at or dealt with much power related items. Mostly software these days.

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k