[MRCA] FYI - Alexanderson SAQ

[Gene Smar]

>From a PVRC member.  Merry Christmas to all y'all.
73 de Gene Smar AD3F 


Sent from my Radio Shack TRS-80 model 100 laptop 
 
   ----- Forwarded Message ----- From: "Frank W3LPL" <donovanf at starpower.net> To: "CWOPS" <main at cwops.groups.io>, "PVRC" <pvrc at mailman.qth.net> Cc: "W1EYH DePetrillo" <marconi at verizon.net>, "W1GS Good" <JBGood1 at Comcast.net>, "w5drc at eastex.net" <w5drc at eastex.net>, "Tess" <k1dt at verizon.net>, "Eric Scace K3NA" <eric at k3na.org> Sent: Wed, Dec 24, 2025 at 1:47 PM Subject: Re: [PVRC] [cwops] SAQ  Hi Zack,
Your description of the RPM of the SAQ Alexandersonalternator rotation speed reflects a fundamental misunderstandingof the principles of operation of the Alexanderson alternator. 
The motor in the SAQ  Alexanderson alternator operates at 720 RPMwhich then feeds a speed increaser gearbox that increases the RPMfeeding to rotor to 2700 RPM. The operating frequency feeding theantenna is the product of 2700 RPM rotator rotation speed andthe number of magnetic poles in the rotor.
The rotor has no conductive windings or electrical connections;it consists of a solid disc of high tensile strength magnetic steel,with narrow slots cut in its circumference to create a series ofnarrow "teeth" that function as magnetic poles.
This is an excellent technical description of the Alexandersonalternator.
https://www.navy-radio.com/xmtrs/vlf/alexanderson-mayes-1975.pdf
This is a superb video of the very complex processof preparing the SAQ alternator for on the air transmission.
https://youtu.be/lbvsHUBM18Y?t=10
73FrankW3LPL



 
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