[Milsurplus] Dual Input Voltage Dynamotors

[gl4d21a at juno.com]

Back in 1955, GE introduced the Progress Line series of 2-way 
radios.  For the high power 25-50 MHz transmitter, a dynamotor was 
required, as the solid state power switching supply did not appear 
until 1959.  Carter manufactured a 600 volt, 300 ma. low profile 
dynamotor with two independent 6 volt primary windings (with 4 
brushes).  These were paralleled  for 6 volt operation (and drew 
about 50 amps) and connected in series for 12 volts.  There were many 
of those radios sold, and a lot of the transmitter and receiver 
strips still floating around, but I have not seen one of the 
dynamotor power supplies in over 25 years, probably longer.  I saw 
fewer Motorola radios, but I believe they had a dual voltage round 
dynamotor in the same time frame, and adopted the 'flat' design 
later, but that may be fiction.

73,
George
W5VPQ


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