On Sun, 25 Jul 2010 09:39:13 -0400, RBM wrote:
It is entirely probable that the OP is looking at a 20 amp 120 volt plug
and not a 20 amp 240 volt plug, which are very similar looking

It was my fault for not explaining clearly.

The plug on the compressor is a NEMA 6-20P (not a NEMA 5-20P); but I do
agree that's a great point to doublecheck.
http://www.jkem.com/pictures/NEMA%20...ng%20Plugs.gif

Here's also what the plate says:
"240V 15 Amp Sears Craftsman model 919.176940".