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From: lucas@a.psy.cmu.edu (pete lucas)
Newsgroups: net.railroad
Subject: re: MORE LIONEL QUESTIONS
Message-ID: <1510@brl-tgr.ARPA>
Date: Sat, 11-Jan-86 23:17:52 EST
Article-I.D.: brl-tgr.1510
Posted: Sat Jan 11 23:17:52 1986
Date-Received: Fri, 17-Jan-86 01:42:32 EST
Sender: news@brl-tgr.ARPA
Lines: 24

The whistle controllers on the old Lionel transformers did not replace the
AC power with DC, but simply superimposed a DC component onto the AC.  There
was a momentary hit of about 5 volts to close the relay, followed by a
holding voltage of about 3 volts.  The transformers also also added a few
extra volts of AC to compensate for the voltage drop across the rectifier and
the drain of the whistle motor.  There was no rectification or electronics
of any kind on board the engine. The whistle relay was simply designed such
that it only responded to DC.  Whereas steam whistles used AC motors and
impellers driving air through a dual-tone whistle chamber, the diesel horns
needed DC buzzers to sound right.  If track voltage were used, the AC
component would have introduced a 60hz hum on the buzzer unless a lot
cleaning up were done, which was not feasible given 1940s technology.
Although engines didn't carry rectification, Lionel DID make some clever use
of the copper-oxide rectifiers used to generate the DC in the transformers.
Ever wonder why the little wooden barrels vibrated UP the ramp of the barrel
loader even though neither the barrels nor the ramp had any asymmetry to
provide for a ratcheting action?  The trick was that a half wave rectifier
caused the ramp's vibration to be asymmetrical, imparting an upward bias
on the motion of the barrels.
                                -pete
P.S. -- I personlly tend to get a bit annoyed when this list drifts too
far into discussion of model as opposed to prototype railroad issues.
However, given the slightest provocation, I will hypocritically go on
forever on the marvels of the Lionel engineering department. :-)