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Jon Elson[_3_]

wrote:

Since the small transformers included with this set get hot and are too
small I've been using my bench variac through an isolation transformer to
test the train. I tried to see if I could blow the whistle by connecting
my DC power supply to the track, but the current peaked at over 6 amps and
took out the power supply fuse twice. The variac didn't like it either and
started to growl. I figure the train motor as well as the transformer
secondary must be loading the DC supply heavily, and perhaps vice versa.
I'm not really sure whats happening here.
The locomotive motor should work fine on DC. So, just switch the track
between AC (loco only) or DC (loco plus whistle). My guess is the
ancient system just placed a selenium rectifier in series with one
transformer wire to go to pulsating DC. So, you ought to try putting
a silicon rectifier in series with your transformer. The way this works,
as far as I know, is you SUBSTITUTE pulsed DC for AC, not ADDING DC in
series with AC, as you tried. That probably put too much voltage on
the motors. The pulsed DC in the Lionel transformer may cause
saturation of the iron, and it may start buzzing or overheat. If that
is the case, then you'd need to put a bridge rectifier between the
transformer and the track, so the transformer still sees AC only.
I seem to recall the Lionel transformers with the whistle function had
a warning on them to only use the whistle for 10 seconds per minute or
something like that.

Jon