JAY EMRIE wrote in a message to ROBERT SAYRE:

RS>GM> All the auto regulators I've looked are linear. Switched would be
RS>GM> more efficient, in fact the regulator on the aux generator of the
RS>GM> diesel-electric loco that I looked at, apparently used phase
RS>GM> control. But the effect is essentially the same.

RS> The older ones were mechanical. Relays switched the field in and 
RS> out, IIRC. I wouldn't call those linear. ;^)

JE> Those went out in the late 50s - early 60s. From then on it was 
JE> electronic types

The one that I was talking about was in my '67 Fury III...

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