On Sat, 16 Nov 2013 12:05:12 -0500, Ralph Mowery wrote:

As most dryers use the 120 volts from one leg to power the
control circuits and light , the third wire is acting as a neutral.

Well, that answers my question as to whether the neutral is carrying
current.

Since there are 120v "things" on that dryer (e.g., the timer, the
bulbs, etc.), there *must* be some current in that neutral (unless
the loads are perfectly balanced).

So, in the case of my 3-wire dryer, the neutral is always carrying
current, whereas a ground wire shouldn't normally be carrying current
(because once you carry current, there is a chance that there will
be resistance, and if there is resistance, you get a potential,
whether you like it or not).

So, maybe, just maybe, my spark, is due to a high-resistance neutral?
Geez. How do I check for a high-resistance neutral?