So on smoke unit fan motors that do not have the polarity marked, is the white dot side positive or negative? Thanks.
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Dot = Positive.
However some smoke unit designs are not what they seem.
The fluid dynamics vary with the type of impeller and exit design of the fan chamber.
Bottom line.. try it both ways if in doubt.
Most fan driven smoke units should run CW when viewed from the top. I have seen one that ran CCW, but it was the exception that proved the rule. Don't be fooled by the fan blades curving away from rotation, the convex part actually goes forward, it reduces the fan noise.
Thanks guys. The reason I ask, is the smoke unit has a red and a black wire. I assumed the red was positive and the black was negative. However, the black dot is connected to the white dot side of the motor. I'm installing John's Super Chuffer and want to make sure I make the connections to the smoke unit correctly.
Lionel didn't seem to mind which color they used for positive, I've seen them wired both ways. I use a small bench supply, or you can just use a 1.5V battery, to check the rotation direction. Other than one example I've seen, I've always seen the fan rotate CW when connected properly. If there's a white dot, that should ID the positive lead, but being somewhat pedantic, I'll usually verify it. Obviously, for the Super-Chuffer, the positive goes to the +5V lead from the Super-Chuffer.
