GreyQ - notice that wire on the motor that comes out from under the pully and goes under the motor and into the case - does your motor that? From what you've posted, it sort of sounds like the wire from the motor is missing.
if you don't have the type of connection Joe shows, you could easily either hard wire them together, or use another type of connector (a Singer one will work too) all they are is a block that facilitates getting the right wires connected to each other. It's very nice to have it easy to unconnect too.
Joe, I hope the machine I'm getting is wired like yours. It looks very similar but there are not good pictures of the connection at the box. what ever is there, it will be simple enough to get a three prong plug, male and female ends and wire them up in this configuration.
Though I'm not sure I want to keep that machine electric anyway . . .